Multiplanar Reconstruction Improves Early Diagnosis of Occult Local Tumor Progression after Microwave Ablation for Hepatocellular Carcinoma

Multiplanar Reconstruction Improves Early Diagnosis of Occult Local Tumor Progression after Microwave Ablation for Hepatocellular Carcinoma | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Multiplanar Reconstruction Improves Early Diagnosis of Occult Local Tumor Progression after Microwave Ablation for Hepatocellular Carcinoma Zhi Zhu, Mingyu Zhang, Fengcan Cai, Wenxi Chen, Yuanyong Zhou, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7295056/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Objective To investigate early diagnosis feasibility and imaging manifestations of local tumour progression (LTP) after hepatocellular carcinoma (HCC) ablation. Methods Retrospective analysis of 62 HCC patients (78 nodules) treated with microwave ablation. Two radiologists independently reviewed conventional axial and multiplanar reconstruction (MPR) images using a double-blind method to analyse early LTP features and diagnostic efficacy. Results Postoperative LTP was diagnosed in 23/78 nodules. MPR significantly improved LTP detection sensitivity for both observers (0.65 vs. 0.96; P < 0.05). Inter-observer agreement was excellent. LTP lesions at ablation zone superior/inferior margins, in unfavorable locations, or showing arterial non-enhancement with portal/delayed phase washout and "cloud-like" morphology were more occult. Median time to clinical LTP diagnosis was 16 months. With MPR assistance, observers diagnosed LTP earlier (median 15 months). Conclusion Multiphasic CE-CT combined with MPR enables early diagnosis of LTP. This study describes the imaging characteristics of occult LTP lesions that are easily overlooked. Microwave ablation Computer Tomography Local Tumour Progression Figures Figure 1 Figure 2 Simple Summary Multi-planar reconstruction (MPR) of follow-up images after liver cancer ablation, based on existing image post-processing technologies, can significantly improve the diagnostic efficacy of local tumour progression (LTP). This technology analyses the anatomical structure of the ablation area in multiple dimensions. This overcomes the limitations of traditional axial images when it comes to identifying hidden locations, such as the liver margin or diaphragm, and atypical enhancement lesions, such as 'cloud-like' clearance. This enables radiologists to make an LTP diagnosis earlier (with a median diagnostic time reduction of 2 months) and more accurately (with sensitivity improving from 0.65 to 0.96). This provides critical evidence for the timely initiation of secondary curative intervention and ultimately optimises patient outcomes. Key Points The identification of local tumour progression through the re-examination of earlier follow-up images. The multi-planar reconstruction of images represents a significant method of assessment. The diagnosis of local tumour progression can be made at an earlier stage. Introduction Local tumor progression (LTP) after ablation therapy for hepatocellular carcinoma (HCC, hereafter referred to as liver cancer) is a critical factor affecting long-term patient prognosis. Although microwave ablation (MWA) is widely recommended as a first-line treatment option for inoperable HCC due to its minimally invasive and repeatable nature[ 1 , 2 ], the post-operative LTP rate remains high (15%-20%)[ 3 ], and early diagnosis poses significant challenges. Conventional imaging follow-up relies on visual assessment of multiphasic CE-CT axial images. However, factors such as acute inflammatory reactions at the ablation zone margin, partial volume effects, and lesion location obscurity (e.g., adjacent to the diaphragm or blood vessels) often lead to missed or misinterpreted early signs of LTP[ 4 – 7 ]. Consequently, patients may miss the optimal window for secondary radical intervention. There is an urgent need to overcome the limitations of current imaging techniques for the early diagnosis of LTP. Multiple studies suggest that subclinical residual lesions after ablation may progress to radiologically detectable LTP within months[ 8 , 9 ], and early identification of these lesions is crucial for improving prognosis[ 6 , 5 ]. Although European Association for the Study of the Liver (EASL) guidelines recommend multiphasic CE-CT or MRI as the cornerstone of post-operative follow-up[ 2 ], conventional axial images, limited by single-plane resolution, often struggle to accurately distinguish inflammatory reactions from tumor residue. Multiplanar reconstruction (MPR) technology, by providing three-dimensional spatial analysis of the ablation zone anatomy, is considered capable of significantly reducing misjudgment due to partial volume effects[ 10 , 11 ]. However, its incremental value in the early diagnosis of LTP has not been systematically validated. Methods This single-center retrospective cohort study strictly adhered to the ethical principles of the Declaration of Helsinki. The study protocol was approved by the Ethics Committee of Shunde Hospital, Guangzhou University of Chinese Medicine (Approval No. KY-2024155), and patient informed consent was waived due to the retrospective nature of the study. Patients who underwent MWA for HCC at our institution between March 2018 and March 2023 were retrospectively analyzed.Inclusion criteria: (1) HCC diagnosis confirmed according to EASL guidelines via pathology and/or non-invasive criteria (i.e., typical imaging features on multiphasic CT, dynamic contrast-enhanced MRI, or CEUS); (2) Patients who underwent a complete ablation procedure at our institution; (3) Availability of complete pre-operative imaging and ≥ 3 regular follow-up imaging studies (including images at LTP diagnosis).Exclusion criteria: (1) History of other malignancies; (2) Follow-up duration < 6 months; (3) Image quality insufficient for diagnosis or missing key image data; (4) Palliative ablation treatment; (5) Receipt of other local therapies after MWA. An intra-individual control design was employed. Cases with HCC lesions confirmed by imaging to have achieved complete ablation were included. Through regular follow-up with multiphasic CE-CT or MRI and serum alpha-fetoprotein (AFP) level monitoring, LTP was diagnosed by a multidisciplinary team (MDT) (including radiologists, oncologists, and interventional radiologists) based on consensus integrating imaging findings and serum AFP levels when enhancing lesions or lesion growth were detected at the ablation zone margin. All patient CT datasets were collected, anonymized by removing patient identifiers and clinical diagnoses via the PACS system, and renamed with random codes. Two blinded observers then independently performed LTP diagnostic analysis. By analyzing follow-up multiphasic CE-CT images, the accuracy, sensitivity, and specificity of diagnosing LTP using axial CE-CT images alone versus MPR-assisted CE-CT images were compared. Furthermore, using the time of clinical diagnosis as the reference standard, the time points of LTP diagnosis by the blinded observers were compared to assess the value of MPR-reconstructed multiphasic CE-CT for early LTP diagnosis. Blinded Observer LTP Diagnostic Analysis Pre-treatment (most recent prior to ablation) and post-operative follow-up images were anonymized and randomly assigned to two observers (Observer 1: 8 years; Observer 2: 12 years of hepatobiliary imaging experience) for independent evaluation. Observers were only aware that the patient had undergone ablation and were blinded to all other clinical information, prior image reports, and final diagnoses. The first evaluation provided only time-stamped axial multiphasic contrast-enhanced abdominal CT images (5mm and 1mm slice thickness). Both observers recorded lesion location, morphology, enhancement pattern, and diagnosis time. In the re-evaluation phase, MPR images were added to the same cases, which were then randomly reassigned to the two observers for re-evaluation, with results recorded again. To minimize recall bias, a minimum interval of 4 weeks was mandated between evaluations. To ensure consistency and accuracy, prior to the study, observers were provided with the following LTP diagnostic criteria: (a) Enhancement within or at the margin (≤ 5mm) of the ablation zone with washout; (b) Enhancement within or at the margin (≤ 5mm) of the ablation zone without washout; (c) Washout in the portal or delayed phase within or at the margin (≤ 5mm) of the ablation zone with persistent enlargement. Meeting any criterion (a-c) warranted an LTP diagnosis. If criterion (e): Loss of ablation zone margin sharpness, was observed, it suggested suspected LTP but was not definitive. According to mRECIST criteria, if a lesion initially observed did not meet progression criteria but subsequently did, progression was retrospectively assigned to the time of initial observation[ 12 ]. Therefore, if a patient first exhibited criterion (e) and later met definitive LTP criteria, the observer recorded the time criterion (e) appeared as the LTP onset time. Ablation Protocol Determination and Execution Pre-operative tumor assessment was conducted via multidisciplinary team (MDT) consultation, considering patient preference and financial capacity to determine the ablation plan. All procedures were performed percutaneously under local anesthesia with CT guidance by two interventional radiologists with over ten years of experience in liver cancer ablation. Ablation modality, power (typically 50–65 W), and duration (typically 5–10 min) were determined based on lesion size. Complete tumor destruction was achieved via single or overlapping ablations to ensure an ablation zone extending ≥ 5–10 mm beyond the tumor margins. CT and MRI Image Acquisition All patients underwent multiphasic CE-CT using a third-generation dual-source CT scanner (SOMATOM Force, Siemens Healthineers, Germany). Scanning parameters: Tube voltage 120 kV; Tube current 280 mA; Pitch 0.9-1; Rotation time 0.40–0.80 s; Field of view 300–350 mm; Matrix 512×512; Slice thickness 5 mm. Non-ionic iodinated contrast medium (1.5 ml/kg) was administered intravenously via the antecubital vein at 3–4 ml/s. Unenhanced, arterial (30–45 s post-injection start), portal (65–80 s), and delayed (180–205 s) phase images were acquired. MRI was performed using a Siemens VIDA 3.0T scanner. Sequences included T1 VIBE DIXON pre-contrast and 6 dynamic phases: Arterial early phase (15s). Contrast agents used: Gadovist (Gadobutrol), Magnevist (Gadopentetate dimeglumine), or Primovist (Gadoxetate disodium) at a dose of 0.1 mmol/kg body weight (0.2 ml/kg). Follow-up Patients adhered strictly to guideline-recommended follow-up. Follow-up included serum AFP and imaging (multiphasic CE-CT or MRI of the abdomen) every 3 months for the first 2 years post-treatment, and every 3–6 months thereafter. Follow-up was censored on March 31, 2024. Statistical Analysis Statistical analyses were performed using SPSS version 25.0 (IBM). Normality of continuous variables was assessed using the Shapiro-Wilk test. Normally distributed data are presented as mean ± standard deviation (x̄ ± s), non-normally distributed data as median with interquartile range (M (Q1, Q3)), and categorical data as frequencies and percentages. Quantitative data were compared using the t-test; Qualitative data were compared using the Chi-square test or Fisher's exact test. All statistical tests were two-sided, and P < 0.05 was considered statistically significant. Results Patient characteristics A total of 78 HCC nodules in 62 patients were included. Table 1 shows the baseline patient characteristics. HCC diagnosis was confirmed pathologically in 14 patients and clinically in 48 patients. All 78 nodules in 62 patients were assessed as achieving complete ablation on post-procedure imaging (technical success rate 100%). All patients were followed for ≥ 6 months, with a median follow-up time of 18.5 months (IQR 11.0, 34.75). Table 1 Baseline characteristics of the 62 patients. Age, year, Mean ± SD 59.5 ± 1.3(56.9–62.0) Sex (Male/Female) 57/5 Hepatitis(others/HBV-related/HCV-related/alcoholic) 19/39/2/2 Ascites (None/Light/Medium) 59/1/2 Child-Pugh Class (A/B) 52/10 BCLC(0/A) 20/42 AFP(≤400/>400ng/mL) 49/13 Serum albumin (g/dL), Median (IQR) 40.5(34.3,44.0) Total bilirubin (umol/L), Median (IQR) 14.1(8.7,22.8) Tumor size (cm), Median (range) 2.5(1.6,6.1) Tumor number (1/2/3) 48/12/2 Number of MWA(1/2/3) 64/10/4 Abbreviations: HBV, hepatitis B virus ; HCV, hepatitis C virus ;AFP, alpha fetoprotein; MWA, microwave ablation Blinded Observer Diagnostic Performance for LTP The accuracy, sensitivity, specificity and positive and negative predictive values for the LTP of two observers are displayed in Table 2. Accuracy, sensitivity, specificity, PPV, and NPV were generally higher when using axial CE-CT combined with MPR compared to axial CE-CT alone(Table 2). Sensitivity significantly improved for both observers (Observer 1: 0.65 vs. 0.96, P = 0.016; Observer 2: 0.65 vs. 0.96, P = 0.039)(Table 2). Per-nodule analysis showed excellent inter-observer agreement for both axial CE-CT alone (κ: 0.82) and axial CE-CT combined with MPR (κ: 0.88). Table 2. A tumor-by-tumor diagnostic performance of axial CE-CT combined with MPR and axial CE-CT alone for LTP Axial CE-CT alone Axial CE-CT combined with MPR P value tumors,n 95% CI tumors,n 95% CI Observer 1 Sensitivity 0.65 15/23 0.46–0.85 0.96 22/23 0.88-1.00 0.016 Specificity 0.95 52/55 0.89-1.00 0.96 53/55 0.92-1.00 1.000 Accuracy 0.86 67/78 0.78–0.94 0.96 75/78 0.92-1.00 - PPV 0.83 15/18 0.66-1.00 0.92 22/24 0.80-1.00 - NPV 0.87 52/60 0.78–0.95 0.98 53/54 0.95-1.00 - Observer 2 Sensitivity 0.65 15/23 0.46–0.85 0.96 22/23 0.88-1.00 0.039 Specificity 0.93 51/55 0.86-1.00 0.98 54/55 0.95-1.00 0.375 Accuracy 0.85 66/78 0.77–0.93 0.97 76/78 0.94-1.00 - PPV 0.79 15/19 0.61–0.97 0.96 22/23 0.88-1.00 - NPV 0.86 51/59 0.78–0.95 0.98 54/55 0.95-1.00 - PPV, positive predictive value; NPV, negative predictive value. Imaging Characteristics of LTP Analysis of lesions where LTP occurred revealed that it frequently occurred in unfavourable locations (near the diaphragm, the margin of the liver, major blood vessels (diameter > 5 mm), the gallbladder, etc.) or at the upper or lower margins of the ablation zone. ( Fig. 1 ,Fig. 2 )Assessment results from two observers indicated (Table 3 )that relying solely on axial multi-phase enhanced CT images makes it difficult to promptly diagnose LTP in the aforementioned locations without the assistance of MPR. In terms of morphology and enhancement characteristics, nodular LTP with arterial phase enhancement and portal vein or delayed phase washout is more common. However, 'cloud-like' LTPs with no arterial phase enhancement and portal vein or delayed phase clearance are difficult to identify using axial enhanced CT alone.( Fig. 1 ) Table 3 Detection of LTP Imaging Features by Observers Feature Observer 1 Observer 2 Axial CE-CT Alone Axial CE-CT + MPR Axial CE-CT Alone Axial CE-CT + MPR Location Superior/Inferior margin 7 12 6 12 Unfavorable location¹ 4 8 5 9 Peripheral 4 4 4 4 Morphology Nodular 14 18 15 18 "Cloud-like" 1 3 0 4 Enhancement Pattern² (a) Enhancement + washout 13 15 12 15 (b) Enhancement without washout 2 4 3 4 (c) Washout + enlargement 0 2 0 3 ¹ Unfavorable locations: near the diaphragm, the margin of the liver, major blood vessels (diameter > 5 mm), the gallbladder. ² Enhancement pattern definitions: (a) Enhancement within or at the margin (≤ 5mm) of the ablation zone with washout; (b) Enhancement within or at the margin (≤ 5mm) of the ablation zone without washout; (c) Washout in the portal or delayed phase within or at the margin (≤ 5mm) of the ablation zone with persistent enlargement. Comparison of LTP Diagnosis Times Tables 4 and 5 compare the benchmark time for diagnosing LTP with the times recorded by the two observers. The median time from treatment completion to MDT-confirmed LTP diagnosis was 16 months (IQR 9.0, 24.5). The time to LTP diagnosis recorded by both observers using axial CE-CT alone was consistent with the clinical diagnosis time (Observer 1: P = .330; Observer 2: P = .532). With MPR assistance, the median time to LTP diagnosis by observers (15 months) was earlier than the clinical diagnosis time (16 months). Compared to axial CE-CT alone, MPR-assisted diagnosis allowed significantly earlier initial detection of LTP (Observer 1: P < .001; Observer 2: P = .007), reducing the median time to LTP detection from 17 months to 15 months. Table 4 Comparison of Reference Standard Time for Diagnosing LTP and Observer 1's Recognition Time Statistical comparison Diagnosis Time (months) Median (IQR) Z P Reference Diagnosis 16(9.0,24.5) - - - Axial CE-CT Alone 17(9.75,30.0) vs.Reference -0.97 0.330 Axial CE-CT + MPR 15(7.0,24.0) vs.Reference -4.05 <.001 vs. Axial CE-CT Alone -3.49 <.001 MPR: Multi-planar reconstruction Table 5 Comparison of Reference Standard Time for Diagnosing LTP and Observer 2's Recognition Time Statistical comparison Diagnosis Time (months) Median (IQR) Z P Reference Diagnosis 16(9.0,24.5) - - - Axial CE-CT Alone 17(9.0,29.25) vs.Reference -0.62 0.532 Axial CE-CT + MPR 15(7.75,24.0) vs.Reference -3.29 0.001 vs. Axial CE-CT Alone -2.68 0.007 MPR: Multi-planar reconstruction Discussion This retrospective cohort study clearly demonstrates that multiphasic CE-CT combined with MPR technology has significantly higher diagnostic sensitivity for detecting post-ablation LTP compared to axial CE-CT alone. Inter-observer agreement for axial CE-CT alone was good, and agreement when using combined MPR was excellent. LTP is a key criterion for evaluating the success of thermal ablation, and its timely detection directly impacts the accuracy of post-operative efficacy assessment[ 13 , 14 ]. This study found that axial CE-CT alone is ineffective for identifying LTP occurring at the superior/inferior margins of the ablation zone or in unfavorable locations. Conversely, axial CE-CT combined with MPR, through multiplanar spatial reconstruction, can more accurately capture early enhancement signs in these regions, significantly advancing the median time to LTP diagnosis from 17 months to 15 months (Observer 1: P < .001; Observer 2: P = .007), achieving a notable improvement in diagnostic timeliness. Pairwise comparisons showed that the time to LTP detection using axial CE-CT alone was consistent with the clinical diagnosis benchmark time (Observer 1: P = .330; Observer 2: P = .532). Due to the disruption of normal liver anatomy by thermal ablation, potential inflammatory reactions surrounding the ablation zone, and partial volume effects, conventional two-dimensional (axial) images struggle to accurately distinguish the tumor ablation zone from normal liver tissue[ 11 , 15 ]. MPR, by providing multiplanar images, allows analysis of selected regions from different angles, overcoming the limitations of single-plane CT. The results of this study indicate that for diagnosing LTP, axial CE-CT combined with MPR outperforms axial CE-CT alone in accuracy, sensitivity, specificity, PPV, and NPV, with a particularly significant improvement in sensitivity. Microwave ablation (MWA) is a technically challenging procedure. Interventional radiologists must preoperatively consider multiple factors, including tumor size, morphology, and location, to achieve a minimum 5–10 mm ablation margin under the goal of radical treatment[ 16 ]. Crucially, the ablation margin (AM) is recognized as a key predictor of LTP after ablation[ 16 , 17 ]. A clear and sharp AM facilitates the distinction between the ablation zone and normal liver tissue and usually signifies technical success. However, the ablation zones generated by commonly used MWA systems are typically ellipsoidal (longer radially, shorter axially)[ 18 , 19 ]. This morphology is disadvantageous for spherical tumors, as the ablation zone may fail to provide sufficient margins to fully cover the target tumor. For tumors in unfavorable locations, the heat-sink effect may also lead to residual microscopic disease and microvascular invasion (MVI) escaping ablation, which is closely associated with LTP development[ 20 – 23 ]. Consequently, the efficacy at the superior/inferior margins and unfavorable locations may be underestimated during routine post-operative axial imaging evaluation. This explains why LTP in this study predominantly occurred at these sites. In summary, LTP lesions located at the superior/inferior margins or unfavorable positions, exhibiting arterial non-enhancement, portal/delayed phase washout, and a "cloud-like" enhancement morphology, present occult features on single-plane images and are more difficult to identify. In contrast, MPR technology leverages its advantage in displaying spatial relationships across multiple planes to enable earlier LTP detection. This study has several limitations. First, it is a single-center retrospective study with a limited sample size, potentially introducing selection bias. Second, the study spanned a considerable period during which operator experience and ablation technology itself may have evolved, potentially influencing outcomes. Third, follow-up imaging for some patients was relatively homogeneous, lacking supplementary MRI examinations. Radiomics, by extracting deep imaging features invisible to the naked eye and providing more specific, objective quantitative data, could offer a more precise evaluation of the ablation margin post-procedure. However, research utilizing radiomics for diagnosing post-ablation LTP is currently scarce. Future studies will focus on establishing a radiomics diagnostic model for LTP after liver cancer ablation through large-scale, multi-center efforts to achieve early diagnosis. In conclusion, the findings of this study indicate that follow-up strategies should be intensified, with a specific focus on evaluating the superior/inferior margins and unfavorable locations of the ablation zone. Axial multiphasic CE-CT combined with MPR technology significantly optimizes LTP diagnostic efficacy through multiplanar analysis, markedly improving sensitivity and enabling earlier diagnosis, particularly for lesions in occult locations. This provides high-level evidence for optimizing precise follow-up strategies after HCC ablation. Abbreviations AFP Alpha fetoprotein AM Ablation margin CEUS Contrast-enhanced ultrasound CT Computer tomography HBV Hepatitis B virus HBV Hepatitis C virus HCC Hepatocellular carcinoma LTP Local tumor progression MDT Multidisciplinary team MPR Multi-planar reconstruction MRI Magnetic resonance imaging MWA Microwave ablation MVI Microvascular invasion TBIL Total bilirubin Declarations Authors' contributions Zhu,Z.: research design, data collection, data organization,statistical analysis, and paper writing. Zhang,M.Y.: data collection, statistical analysis. Cai,F.C.: data collection, data organization Chen,W.X.: statistical analysis, data collection. Wu,Q.D.: research design, paper review, and research supervision. Zhou,Y.Y.: paper review, and research supervision. All authors read and approved the final manuscript. Ethics approval and consent to participate This study was approved by the Ethics Committee of Shunde Hospital, Guangzhou University of Chinese Medicine (Approval No. KY-2024155) and conducted in accordance with the Declaration of Helsinki. Informed consent was waived by the Ethics Committee due to the retrospective nature of the study. Consent for publication Not Applicable. Availability of data and material The datasets analysed during the current study are not publicly available due to ethical restrictions but are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests Funding The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgements Not applicable References Singal AG, Llovet JM, Yarchoan M, Mehta N, Heimbach JK, Dawson LA, et al. AASLD Practice Guidance on prevention, diagnosis, and treatment of hepatocellular carcinoma. Hepatology. 2023;78(6):1922–65. https://doi.org/10.1097/HEP.0000000000000466 . EASL Clinical Practice Guidelines. Management of hepatocellular carcinoma. J Hepatol. 2018;69(1):182–236. https://doi.org/10.1016/j.jhep.2018.03.019 . Ding WZ, Liu S, Liu F, Cheng Z, Yu X, Han ZY, et al. Are all local tumour progressions of HCC related to thermal ablation? A study of the causes and classification of local tumour progression. Eur Radiol. 2022;32(12):8518–26. https://doi.org/10.1007/s00330-022-08913-1 . Park MH, Rhim H, Kim YS, Choi D, Lim HK, Lee WJ. Spectrum of CT findings after radiofrequency ablation of hepatic tumors. Radiographics. 2008;28(2):379–90. https://doi.org/10.1148/rg.282075038 . 390-2. Minami Y, Nishida N, Kudo M, World. J Gastroentero. 2014;20(15):4160–6. https://doi.org/10.3748/wjg.v20.i15.4160 . Lee MW, Kang D, Lim HK, Cho J, Sinn DH, Kang TW, et al. Updated 10-year outcomes of percutaneous radiofrequency ablation as first-line therapy for single hepatocellular carcinoma < 3 cm: emphasis on association of local tumor progression and overall survival. Eur Radiol. 2020;30(4):2391–400. https://doi.org/10.1007/s00330-019-06575-0 . Cao S, Lyu T, Fan Z, Guan H, Song L, Tong X, et al. Long-term outcome of percutaneous radiofrequency ablation for periportal hepatocellular carcinoma: tumor recurrence or progression, survival and clinical significance. Cancer Imaging. 2022;22(1):2. https://doi.org/10.1186/s40644-021-00442-2 . Baumler W, Wiggermann P, Lurken L, Dollinger M, Stroszczynski C, Beyer LP, et al. Early Detection of Local Tumor Progression after Irreversible Electroporation (IRE) of a Hepatocellular Carcinoma Using Gd-EOB-DTPA-Based MR Imaging at 3T. Cancers. 2021;13(7). https://doi.org/10.3390/cancers13071595 . Baumler W, Beyer LP, Lurken L, Wiggermann P, Stroszczynski C, Dollinger M, et al. Detection of Incomplete Irreversible Electroporation (IRE) and Microwave Ablation (MWA) of Hepatocellular Carcinoma (HCC) Using Iodine Quantification in Dual Energy Computed Tomography (DECT). Diagnostics. 2022;12(4). https://doi.org/10.3390/diagnostics12040986 . Park Y, Choi D, Rhim H, Kim YS, Lee JY, Chang I, et al. Central lower attenuating lesion in the ablation zone on immediate follow-up CT after percutaneous radiofrequency ablation for hepatocellular carcinoma: incidence and clinical significance. Eur J Radiol. 2010;75(3):391–6. https://doi.org/10.1016/j.ejrad.2009.04.054 . Kim YS, Lee WJ, Rhim H, Lim HK, Choi D, Lee JY. The minimal ablative margin of radiofrequency ablation of hepatocellular carcinoma (> 2 and < 5 cm) needed to prevent local tumor progression: 3D quantitative assessment using CT image fusion. Am J Roentgenol. 2010;195(3):758–65. https://doi.org/10.2214/AJR.09.2954 . Llovet JM, Lencioni R. mRECIST for HCC: Performance and novel refinements. J Hepatol. 2020;72(2):288–306. https://doi.org/10.1016/j.jhep.2019.09.026 . Lee SR, Kilcoyne A, Kambadakone A, Arellano R. Interventional oncology: pictorial review of post-ablation imaging of liver and renal tumors. Abdom Radiol. 2016;41(4):677–705. https://doi.org/10.1007/s00261-016-0665-3 . Vandenbroucke F, Vandemeulebroucke J, Buls N, Thoeni RF, de Mey J. Can tumor coverage evaluated 24 h post-radiofrequency ablation predict local tumor progression of liver metastases? Int J Comput Ass Rad. 2018;13(12):1981–9. https://doi.org/10.1007/s11548-018-1765-z . Paolucci I, Albuquerque MSJ, Lin YM, Shieh A, Ierardi AM, Caraffiello G, et al. Quantitative Ablation Confirmation Methods in Percutaneous Thermal Ablation of Malignant Liver Tumors: Technical Insights, Clinical Evidence, and Future Outlook. Radiol Imaging Cancer. 2025;7(3):e240293. https://doi.org/10.1148/rycan.240293 . Nakazawa T, Kokubu S, Shibuya A, Ono K, Watanabe M, Hidaka H, et al. Radiofrequency ablation of hepatocellular carcinoma: correlation between local tumor progression after ablation and ablative margin. Am J Roentgenol. 2007;188(2):480–8. https://doi.org/10.2214/AJR.05.2079 . Takeyama N, Mizobuchi N, Sakaki M, Shimozuma Y, Munechika J, Kajiwara A, et al. Evaluation of hepatocellular carcinoma ablative margins using fused pre- and post-ablation hepatobiliary phase images. Abdom Radiol. 2019;44(3):923–35. https://doi.org/10.1007/s00261-018-1800-0 . Farina L, Weiss N, Nissenbaum Y, Cavagnaro M, Lopresto V, Pinto R, et al. Characterisation of tissue shrinkage during microwave thermal ablation. Int J Hyperther. 2014;30(7):419–28. https://doi.org/10.3109/02656736.2014.957250 . Simon CJ, Dupuy DE, Iannitti DA, Lu DS, Yu NC, Aswad BI, et al. Intraoperative triple antenna hepatic microwave ablation. Am J Roentgenol. 2006;187(4):W333–40. https://doi.org/10.2214/AJR.05.0804 . Imamura H, Matsuyama Y, Tanaka E, Ohkubo T, Hasegawa K, Miyagawa S, et al. Risk factors contributing to early and late phase intrahepatic recurrence of hepatocellular carcinoma after hepatectomy. J Hepatol. 2003;38(2):200–7. https://doi.org/10.1016/s0168-8278(02)00360-4 . Erstad DJ, Tanabe KK. Prognostic and Therapeutic Implications of Microvascular Invasion in Hepatocellular Carcinoma. Ann Surg Oncol. 2019;26(5):1474–93. https://doi.org/10.1245/s10434-019-07227-9 . Xia T, Zhou Z, Meng X, Zha J, Yu Q, Wang W, et al. Predicting Microvascular Invasion in Hepatocellular Carcinoma Using CT-based Radiomics Model. Radiology. 2023;307(4):e222729. https://doi.org/10.1148/radiol.222729 . Park Y, Choi D, Lim HK, Rhim H, Kim YS, Kim SH, et al. Growth rate of new hepatocellular carcinoma after percutaneous radiofrequency ablation: evaluation with multiphase CT. Am J Roentgenol. 2008;191(1):215–20. https://doi.org/10.2214/AJR.07.3297 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers invited by journal 04 Sep, 2025 Editor assigned by journal 02 Sep, 2025 Editor invited by journal 11 Aug, 2025 Submission checks completed at journal 11 Aug, 2025 First submitted to journal 11 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7295056","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":512652477,"identity":"57159cbc-661e-4c2a-a974-86da72290015","order_by":0,"name":"Zhi Zhu","email":"","orcid":"","institution":"ShunDe hospital of Guangzhou University of Chinese medician","correspondingAuthor":false,"prefix":"","firstName":"Zhi","middleName":"","lastName":"Zhu","suffix":""},{"id":512652478,"identity":"aab4dc48-58fc-4b75-8aa9-e3f42ff1917e","order_by":1,"name":"Mingyu Zhang","email":"","orcid":"","institution":"ShunDe hospital of Guangzhou University of Chinese medician","correspondingAuthor":false,"prefix":"","firstName":"Mingyu","middleName":"","lastName":"Zhang","suffix":""},{"id":512652479,"identity":"602dd3e8-e4e4-4d9c-8076-452beb4c39ac","order_by":2,"name":"Fengcan Cai","email":"","orcid":"","institution":"ShunDe hospital of Guangzhou University of Chinese medician","correspondingAuthor":false,"prefix":"","firstName":"Fengcan","middleName":"","lastName":"Cai","suffix":""},{"id":512652480,"identity":"b9ff679e-9930-49fa-9867-f7fd3d96e5e5","order_by":3,"name":"Wenxi Chen","email":"","orcid":"","institution":"ShunDe hospital of Guangzhou University of Chinese medician","correspondingAuthor":false,"prefix":"","firstName":"Wenxi","middleName":"","lastName":"Chen","suffix":""},{"id":512652481,"identity":"0620a9d5-220a-4165-b914-ae6b9b643d93","order_by":4,"name":"Yuanyong Zhou","email":"","orcid":"","institution":"ShunDe hospital of Guangzhou University of Chinese medician","correspondingAuthor":false,"prefix":"","firstName":"Yuanyong","middleName":"","lastName":"Zhou","suffix":""},{"id":512652482,"identity":"6e386119-a97c-4843-b574-0bfb1677283a","order_by":5,"name":"Qingde Wu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAxElEQVRIiWNgGAWjYJCCAwwMzAxs7A1AkiQtfDwHSNDCANIiJ5FApBaDG8kbDxf8spZjk3z+8HFhG4M8v9gBQlrSCg7P7Es3ZpPOMTae2cZgOHN2An4tZjdyDA7z9hxObJPOYZPmbWNIMLhNpJb6Nsnjz0jQwvPjcAKbBIMZcVrszzwrOMzbkG7YxgP0C885CcJ+kWxP3vyZ54+1vHz78YePecps5PmlCWgBAgMGxjY4R4KgcogWhj9EKRwFo2AUjIKRCgD/gEBWo4RSCgAAAABJRU5ErkJggg==","orcid":"","institution":"ShunDe hospital of Guangzhou University of Chinese medician","correspondingAuthor":true,"prefix":"","firstName":"Qingde","middleName":"","lastName":"Wu","suffix":""}],"badges":[],"createdAt":"2025-08-05 01:08:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7295056/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7295056/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":91076542,"identity":"3d481a8e-76ec-4a8b-8da6-cd562b611c48","added_by":"auto","created_at":"2025-09-11 11:10:51","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":829623,"visible":true,"origin":"","legend":"\u003cp\u003eA 39-year-old patient with hepatitis B-related hepatocellular carcinoma (HCC) achieved curative treatment with microwave ablation (MWA) (A). LTP was diagnosed 54 months post-ablation (B, C), showing a lesion (arrows) adjacent to the liver edge (an unfavorable location) with atypical enhancement characteristics (washout in both arterial and portal venous phases), which is highly susceptible to being missed on axial images. When employing single-plane multi-phase enhanced CT to evaluate follow-up images at an early time point (48 months post-ablation), no significant abnormalities were observed in either the arterial phase (D) or the portal venous phase (E). However, re-evaluation of the same 48-month images with multiplanar reconstruction (MPR) assistance (coronal plane, F) clearly revealed a washout nodule (arrow) near the liver edge within the ablation zone, highly suggestive of LTP.This early diagnosis at 48 months identified a stage where the disease was potentially still amenable to repeat ablation therapy for controlling progression.By the time LTP was clinically confirmed at 54 months (B, C), multiple intrahepatic metastases had already developed (G, arrows), making curative ablation no longer feasible.Unfortunately, the disease progressed rapidly. Merely 3 months later (H, I), multiphase contrast-enhanced CT demonstrated diffuse intrahepatic metastasis.\u003c/p\u003e","description":"","filename":"FIG1.png","url":"https://assets-eu.researchsquare.com/files/rs-7295056/v1/ca4b6092afca1bcbe390f5f6.png"},{"id":91074375,"identity":"7d375a2b-c389-4f9f-8078-262405c02f56","added_by":"auto","created_at":"2025-09-11 11:02:51","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":736477,"visible":true,"origin":"","legend":"\u003cp\u003eA 74-year-old patient with cirrhosis achieved curative treatment for hepatocellular carcinoma (HCC) with microwave ablation (MWA) (A). LTP was diagnosed 26 months post-ablation (B-E), showing a lesion (arrows) located at the inferior margin of the ablation zone, a location susceptible to being missed on axial images.Evaluation of earlier follow-up images at 18 months post-ablation using axial multiphase contrast-enhanced CT alone revealed no significant abnormality on arterial (F) or portal venous (G) phase images.However, re-evaluation of the same 18-month images with multiplanar reconstruction (MPR) assistance (coronal plane, H) clearly revealed an enhancing nodule (arrow) at the inferior margin of the ablation zone, highly suggestive of LTP.The patient underwent repeat ablation therapy 1 month after LTP diagnosis. Follow-up imaging (I) demonstrated a favorable treatment response.\u003c/p\u003e","description":"","filename":"FIG2.png","url":"https://assets-eu.researchsquare.com/files/rs-7295056/v1/6204093d76c5e78795c7f71b.png"},{"id":91078197,"identity":"d87185f0-e0ce-407c-97bb-0ee86980a634","added_by":"auto","created_at":"2025-09-11 11:18:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2862209,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7295056/v1/32cbebd0-38e3-442a-a7f2-4ae6632ed216.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Multiplanar Reconstruction Improves Early Diagnosis of Occult Local Tumor Progression after Microwave Ablation for Hepatocellular Carcinoma","fulltext":[{"header":"Simple Summary","content":"\u003cp\u003eMulti-planar reconstruction (MPR) of follow-up images after liver cancer ablation, based on existing image post-processing technologies, can significantly improve the diagnostic efficacy of local tumour progression (LTP). This technology analyses the anatomical structure of the ablation area in multiple dimensions. This overcomes the limitations of traditional axial images when it comes to identifying hidden locations, such as the liver margin or diaphragm, and atypical enhancement lesions, such as \u0026apos;cloud-like\u0026apos; clearance. This enables radiologists to make an LTP diagnosis earlier (with a median diagnostic time reduction of 2 months) and more accurately (with sensitivity improving from 0.65 to 0.96). This provides critical evidence for the timely initiation of secondary curative intervention and ultimately optimises patient outcomes.\u003c/p\u003e"},{"header":"Key Points","content":"\u003cul start=\"50\"\u003e\n \u003cli\u003eThe identification of local tumour progression through the re-examination of earlier follow-up images.\u003c/li\u003e\n \u003cli\u003eThe multi-planar reconstruction of images represents a significant method of assessment.\u003c/li\u003e\n \u003cli\u003eThe diagnosis of local tumour progression can be made at an earlier stage.\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"Introduction","content":"\u003cp\u003eLocal tumor progression (LTP) after ablation therapy for hepatocellular carcinoma (HCC, hereafter referred to as liver cancer) is a critical factor affecting long-term patient prognosis. Although microwave ablation (MWA) is widely recommended as a first-line treatment option for inoperable HCC due to its minimally invasive and repeatable nature[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], the post-operative LTP rate remains high (15%-20%)[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], and early diagnosis poses significant challenges. Conventional imaging follow-up relies on visual assessment of multiphasic CE-CT axial images. However, factors such as acute inflammatory reactions at the ablation zone margin, partial volume effects, and lesion location obscurity (e.g., adjacent to the diaphragm or blood vessels) often lead to missed or misinterpreted early signs of LTP[\u003cspan additionalcitationids=\"CR5 CR6\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Consequently, patients may miss the optimal window for secondary radical intervention.\u003c/p\u003e\u003cp\u003eThere is an urgent need to overcome the limitations of current imaging techniques for the early diagnosis of LTP. Multiple studies suggest that subclinical residual lesions after ablation may progress to radiologically detectable LTP within months[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], and early identification of these lesions is crucial for improving prognosis[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Although European Association for the Study of the Liver (EASL) guidelines recommend multiphasic CE-CT or MRI as the cornerstone of post-operative follow-up[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], conventional axial images, limited by single-plane resolution, often struggle to accurately distinguish inflammatory reactions from tumor residue. Multiplanar reconstruction (MPR) technology, by providing three-dimensional spatial analysis of the ablation zone anatomy, is considered capable of significantly reducing misjudgment due to partial volume effects[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. However, its incremental value in the early diagnosis of LTP has not been systematically validated.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e This single-center retrospective cohort study strictly adhered to the ethical principles of the Declaration of Helsinki. The study protocol was approved by the Ethics Committee of Shunde Hospital, Guangzhou University of Chinese Medicine (Approval No. KY-2024155), and patient informed consent was waived due to the retrospective nature of the study.\u003c/p\u003e\u003cp\u003ePatients who underwent MWA for HCC at our institution between March 2018 and March 2023 were retrospectively analyzed.Inclusion criteria: (1) HCC diagnosis confirmed according to EASL guidelines via pathology and/or non-invasive criteria (i.e., typical imaging features on multiphasic CT, dynamic contrast-enhanced MRI, or CEUS); (2) Patients who underwent a complete ablation procedure at our institution; (3) Availability of complete pre-operative imaging and \u0026ge;\u0026thinsp;3 regular follow-up imaging studies (including images at LTP diagnosis).Exclusion criteria: (1) History of other malignancies; (2) Follow-up duration\u0026thinsp;\u0026lt;\u0026thinsp;6 months; (3) Image quality insufficient for diagnosis or missing key image data; (4) Palliative ablation treatment; (5) Receipt of other local therapies after MWA.\u003c/p\u003e\u003cp\u003eAn intra-individual control design was employed. Cases with HCC lesions confirmed by imaging to have achieved complete ablation were included. Through regular follow-up with multiphasic CE-CT or MRI and serum alpha-fetoprotein (AFP) level monitoring, LTP was diagnosed by a multidisciplinary team (MDT) (including radiologists, oncologists, and interventional radiologists) based on consensus integrating imaging findings and serum AFP levels when enhancing lesions or lesion growth were detected at the ablation zone margin. All patient CT datasets were collected, anonymized by removing patient identifiers and clinical diagnoses via the PACS system, and renamed with random codes. Two blinded observers then independently performed LTP diagnostic analysis. By analyzing follow-up multiphasic CE-CT images, the accuracy, sensitivity, and specificity of diagnosing LTP using axial CE-CT images alone versus MPR-assisted CE-CT images were compared. Furthermore, using the time of clinical diagnosis as the reference standard, the time points of LTP diagnosis by the blinded observers were compared to assess the value of MPR-reconstructed multiphasic CE-CT for early LTP diagnosis.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eBlinded Observer LTP Diagnostic Analysis\u003c/h2\u003e\u003cp\u003ePre-treatment (most recent prior to ablation) and post-operative follow-up images were anonymized and randomly assigned to two observers (Observer 1: 8 years; Observer 2: 12 years of hepatobiliary imaging experience) for independent evaluation. Observers were only aware that the patient had undergone ablation and were blinded to all other clinical information, prior image reports, and final diagnoses.\u003c/p\u003e\u003cp\u003eThe first evaluation provided only time-stamped axial multiphasic contrast-enhanced abdominal CT images (5mm and 1mm slice thickness). Both observers recorded lesion location, morphology, enhancement pattern, and diagnosis time.\u003c/p\u003e\u003cp\u003eIn the re-evaluation phase, MPR images were added to the same cases, which were then randomly reassigned to the two observers for re-evaluation, with results recorded again. To minimize recall bias, a minimum interval of 4 weeks was mandated between evaluations.\u003c/p\u003e\u003cp\u003eTo ensure consistency and accuracy, prior to the study, observers were provided with the following LTP diagnostic criteria: (a) Enhancement within or at the margin (\u0026le;\u0026thinsp;5mm) of the ablation zone with washout; (b) Enhancement within or at the margin (\u0026le;\u0026thinsp;5mm) of the ablation zone without washout; (c) Washout in the portal or delayed phase within or at the margin (\u0026le;\u0026thinsp;5mm) of the ablation zone with persistent enlargement. Meeting any criterion (a-c) warranted an LTP diagnosis. If criterion (e): Loss of ablation zone margin sharpness, was observed, it suggested suspected LTP but was not definitive.\u003c/p\u003e\u003cp\u003eAccording to mRECIST criteria, if a lesion initially observed did not meet progression criteria but subsequently did, progression was retrospectively assigned to the time of initial observation[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Therefore, if a patient first exhibited criterion (e) and later met definitive LTP criteria, the observer recorded the time criterion (e) appeared as the LTP onset time.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eAblation Protocol Determination and Execution\u003c/h3\u003e\n\u003cp\u003ePre-operative tumor assessment was conducted via multidisciplinary team (MDT) consultation, considering patient preference and financial capacity to determine the ablation plan. All procedures were performed percutaneously under local anesthesia with CT guidance by two interventional radiologists with over ten years of experience in liver cancer ablation. Ablation modality, power (typically 50\u0026ndash;65 W), and duration (typically 5\u0026ndash;10 min) were determined based on lesion size. Complete tumor destruction was achieved via single or overlapping ablations to ensure an ablation zone extending\u0026thinsp;\u0026ge;\u0026thinsp;5\u0026ndash;10 mm beyond the tumor margins.\u003c/p\u003e\n\u003ch3\u003eCT and MRI Image Acquisition\u003c/h3\u003e\n\u003cp\u003eAll patients underwent multiphasic CE-CT using a third-generation dual-source CT scanner (SOMATOM Force, Siemens Healthineers, Germany). Scanning parameters: Tube voltage 120 kV; Tube current 280 mA; Pitch 0.9-1; Rotation time 0.40\u0026ndash;0.80 s; Field of view 300\u0026ndash;350 mm; Matrix 512\u0026times;512; Slice thickness 5 mm. Non-ionic iodinated contrast medium (1.5 ml/kg) was administered intravenously via the antecubital vein at 3\u0026ndash;4 ml/s. Unenhanced, arterial (30\u0026ndash;45 s post-injection start), portal (65\u0026ndash;80 s), and delayed (180\u0026ndash;205 s) phase images were acquired.\u003c/p\u003e\u003cp\u003eMRI was performed using a Siemens VIDA 3.0T scanner. Sequences included T1 VIBE DIXON pre-contrast and 6 dynamic phases: Arterial early phase (15s). Contrast agents used: Gadovist (Gadobutrol), Magnevist (Gadopentetate dimeglumine), or Primovist (Gadoxetate disodium) at a dose of 0.1 mmol/kg body weight (0.2 ml/kg).\u003c/p\u003e\n\u003ch3\u003eFollow-up\u003c/h3\u003e\n\u003cp\u003e Patients adhered strictly to guideline-recommended follow-up. Follow-up included serum AFP and imaging (multiphasic CE-CT or MRI of the abdomen) every 3 months for the first 2 years post-treatment, and every 3\u0026ndash;6 months thereafter. Follow-up was censored on March 31, 2024.\u003c/p\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eStatistical analyses were performed using SPSS version 25.0 (IBM). Normality of continuous variables was assessed using the Shapiro-Wilk test. Normally distributed data are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (x̄ \u0026plusmn; s), non-normally distributed data as median with interquartile range (M (Q1, Q3)), and categorical data as frequencies and percentages. Quantitative data were compared using the t-test; Qualitative data were compared using the Chi-square test or Fisher's exact test. All statistical tests were two-sided, and P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003ePatient characteristics\u003c/h2\u003e\u003cp\u003eA total of 78 HCC nodules in 62 patients were included. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the baseline patient characteristics. HCC diagnosis was confirmed pathologically in 14 patients and clinically in 48 patients. All 78 nodules in 62 patients were assessed as achieving complete ablation on post-procedure imaging (technical success rate 100%). All patients were followed for \u0026ge;\u0026thinsp;6 months, with a median follow-up time of 18.5 months (IQR 11.0, 34.75).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eBaseline characteristics of the 62 patients.\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge, year, Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e59.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3(56.9\u0026ndash;62.0)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSex (Male/Female)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e57/5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHepatitis(others/HBV-related/HCV-related/alcoholic)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e19/39/2/2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAscites (None/Light/Medium)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e59/1/2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eChild-Pugh Class (A/B)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e52/10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBCLC(0/A)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e20/42\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAFP(\u0026le;400/\u0026gt;400ng/mL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e49/13\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSerum albumin (g/dL), Median (IQR)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e40.5(34.3,44.0)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTotal bilirubin (umol/L), Median (IQR)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14.1(8.7,22.8)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTumor size (cm), Median (range)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.5(1.6,6.1)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTumor number (1/2/3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e48/12/2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNumber of MWA(1/2/3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e64/10/4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eAbbreviations: HBV, hepatitis B virus ; HCV, hepatitis C virus ;AFP, alpha fetoprotein; MWA, microwave ablation\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eBlinded Observer Diagnostic Performance for LTP\u003c/h3\u003e\n\u003cp\u003eThe accuracy, sensitivity, specificity and positive and negative predictive values for the LTP of two observers are displayed in Table\u0026nbsp;2. Accuracy, sensitivity, specificity, PPV, and NPV were generally higher when using axial CE-CT combined with MPR compared to axial CE-CT alone(Table\u0026nbsp;2). Sensitivity significantly improved for both observers (Observer 1: 0.65 vs. 0.96, P\u0026thinsp;=\u0026thinsp;0.016; Observer 2: 0.65 vs. 0.96, P\u0026thinsp;=\u0026thinsp;0.039)(Table\u0026nbsp;2).\u003c/p\u003e\u003cp\u003e Per-nodule analysis showed excellent inter-observer agreement for both axial CE-CT alone (κ: 0.82) and axial CE-CT combined with MPR (κ: 0.88).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e\u003ccolgroup cols=\"9\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTable\u0026nbsp;2.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"9\" nameend=\"c9\" namest=\"c1\"\u003e\u003cp\u003eA tumor-by-tumor diagnostic performance of axial CE-CT combined with MPR and axial CE-CT alone for LTP\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e\u003cp\u003eAxial CE-CT alone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e\u003cp\u003eAxial CE-CT combined with MPR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e\u003cem\u003eP value\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003etumors,n\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e95% CI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003etumors,n\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e95% CI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eObserver 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSensitivity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15/23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.46\u0026ndash;0.85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e22/23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.88-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.016\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSpecificity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e52/55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.89-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e53/55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.92-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e1.000\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAccuracy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e67/78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.78\u0026ndash;0.94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e75/78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.92-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePPV\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.83\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15/18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.66-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.92\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e22/24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.80-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNPV\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.87\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e52/60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.78\u0026ndash;0.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e53/54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.95-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eObserver 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSensitivity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15/23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.46\u0026ndash;0.85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e22/23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.88-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.039\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSpecificity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.93\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e51/55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.86-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e54/55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.95-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.375\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAccuracy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e66/78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.77\u0026ndash;0.93\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.97\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e76/78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.94-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePPV\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15/19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.61\u0026ndash;0.97\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e22/23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.88-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNPV\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e51/59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.78\u0026ndash;0.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e54/55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.95-1.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"9\" nameend=\"c9\" namest=\"c1\"\u003e\u003cp\u003ePPV, positive predictive value; NPV, negative predictive value.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eImaging Characteristics of LTP\u003c/h2\u003e\u003cp\u003eAnalysis of lesions where LTP occurred revealed that it frequently occurred in unfavourable locations (near the diaphragm, the margin of the liver, major blood vessels (diameter\u0026thinsp;\u0026gt;\u0026thinsp;5 mm), the gallbladder, etc.) or at the upper or lower margins of the ablation zone. ( Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e ,Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)Assessment results from two observers indicated (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\u003e)that relying solely on axial multi-phase enhanced CT images makes it difficult to promptly diagnose LTP in the aforementioned locations without the assistance of MPR. In terms of morphology and enhancement characteristics, nodular LTP with arterial phase enhancement and portal vein or delayed phase washout is more common. However, 'cloud-like' LTPs with no arterial phase enhancement and portal vein or delayed phase clearance are difficult to identify using axial enhanced CT alone.( Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDetection of LTP Imaging Features by Observers\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFeature\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eObserver 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003eObserver 2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAxial CE-CT Alone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAxial CE-CT\u0026thinsp;+\u0026thinsp;MPR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAxial CE-CT Alone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAxial CE-CT\u0026thinsp;+\u0026thinsp;MPR\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLocation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSuperior/Inferior margin\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUnfavorable location\u0026sup1;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePeripheral\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMorphology\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNodular\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\"Cloud-like\"\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eEnhancement Pattern\u0026sup2;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e(a) Enhancement\u0026thinsp;+\u0026thinsp;washout\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e(b) Enhancement without washout\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e(c) Washout\u0026thinsp;+\u0026thinsp;enlargement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e\u003cp\u003e\u0026sup1; Unfavorable locations: near the diaphragm, the margin of the liver, major blood vessels (diameter\u0026thinsp;\u0026gt;\u0026thinsp;5 mm), the gallbladder.\u003c/p\u003e\u003cp\u003e\u0026sup2; Enhancement pattern definitions:\u003c/p\u003e\u003cp\u003e(a) Enhancement within or at the margin (\u0026le;\u0026thinsp;5mm) of the ablation zone with washout;\u003c/p\u003e\u003cp\u003e(b) Enhancement within or at the margin (\u0026le;\u0026thinsp;5mm) of the ablation zone without washout;\u003c/p\u003e\u003cp\u003e(c) Washout in the portal or delayed phase within or at the margin (\u0026le;\u0026thinsp;5mm) of the ablation zone with persistent enlargement.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003eComparison of LTP Diagnosis Times\u003c/h2\u003e\u003cp\u003eTables\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e4\u003c/span\u003e and \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e5\u003c/span\u003e compare the benchmark time for diagnosing LTP with the times recorded by the two observers. The median time from treatment completion to MDT-confirmed LTP diagnosis was 16 months (IQR 9.0, 24.5). The time to LTP diagnosis recorded by both observers using axial CE-CT alone was consistent with the clinical diagnosis time (Observer 1: P\u0026thinsp;=\u0026thinsp;.330; Observer 2: P\u0026thinsp;=\u0026thinsp;.532). With MPR assistance, the median time to LTP diagnosis by observers (15 months) was earlier than the clinical diagnosis time (16 months). Compared to axial CE-CT alone, MPR-assisted diagnosis allowed significantly earlier initial detection of LTP (Observer 1: P\u0026thinsp;\u0026lt;\u0026thinsp;.001; Observer 2: P\u0026thinsp;=\u0026thinsp;.007), reducing the median time to LTP detection from 17 months to 15 months.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of Reference Standard Time for Diagnosing LTP and Observer 1's Recognition Time\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e\u003cp\u003eStatistical comparison\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDiagnosis Time (months)\u003c/p\u003e\u003cp\u003eMedian (IQR)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eZ\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eReference Diagnosis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e16(9.0,24.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAxial CE-CT Alone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e17(9.75,30.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003evs.Reference\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-0.97\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.330\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eAxial CE-CT\u0026thinsp;+\u0026thinsp;MPR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e15(7.0,24.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003evs.Reference\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-4.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003evs. Axial CE-CT Alone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-3.49\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003eMPR: Multi-planar reconstruction\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of Reference Standard Time for Diagnosing LTP and Observer 2's Recognition Time\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e\u003cp\u003eStatistical comparison\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDiagnosis Time (months)\u003c/p\u003e\u003cp\u003eMedian (IQR)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eZ\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eReference Diagnosis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e16(9.0,24.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAxial CE-CT Alone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e17(9.0,29.25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003evs.Reference\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-0.62\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.532\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eAxial CE-CT\u0026thinsp;+\u0026thinsp;MPR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e15(7.75,24.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003evs.Reference\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-3.29\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003evs. Axial CE-CT Alone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-2.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.007\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003eMPR: Multi-planar reconstruction\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis retrospective cohort study clearly demonstrates that multiphasic CE-CT combined with MPR technology has significantly higher diagnostic sensitivity for detecting post-ablation LTP compared to axial CE-CT alone. Inter-observer agreement for axial CE-CT alone was good, and agreement when using combined MPR was excellent. LTP is a key criterion for evaluating the success of thermal ablation, and its timely detection directly impacts the accuracy of post-operative efficacy assessment[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. This study found that axial CE-CT alone is ineffective for identifying LTP occurring at the superior/inferior margins of the ablation zone or in unfavorable locations. Conversely, axial CE-CT combined with MPR, through multiplanar spatial reconstruction, can more accurately capture early enhancement signs in these regions, significantly advancing the median time to LTP diagnosis from 17 months to 15 months (Observer 1: P\u0026thinsp;\u0026lt;\u0026thinsp;.001; Observer 2: P\u0026thinsp;=\u0026thinsp;.007), achieving a notable improvement in diagnostic timeliness. Pairwise comparisons showed that the time to LTP detection using axial CE-CT alone was consistent with the clinical diagnosis benchmark time (Observer 1: P\u0026thinsp;=\u0026thinsp;.330; Observer 2: P\u0026thinsp;=\u0026thinsp;.532).\u003c/p\u003e\u003cp\u003eDue to the disruption of normal liver anatomy by thermal ablation, potential inflammatory reactions surrounding the ablation zone, and partial volume effects, conventional two-dimensional (axial) images struggle to accurately distinguish the tumor ablation zone from normal liver tissue[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. MPR, by providing multiplanar images, allows analysis of selected regions from different angles, overcoming the limitations of single-plane CT. The results of this study indicate that for diagnosing LTP, axial CE-CT combined with MPR outperforms axial CE-CT alone in accuracy, sensitivity, specificity, PPV, and NPV, with a particularly significant improvement in sensitivity.\u003c/p\u003e\u003cp\u003eMicrowave ablation (MWA) is a technically challenging procedure. Interventional radiologists must preoperatively consider multiple factors, including tumor size, morphology, and location, to achieve a minimum 5\u0026ndash;10 mm ablation margin under the goal of radical treatment[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Crucially, the ablation margin (AM) is recognized as a key predictor of LTP after ablation[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. A clear and sharp AM facilitates the distinction between the ablation zone and normal liver tissue and usually signifies technical success. However, the ablation zones generated by commonly used MWA systems are typically ellipsoidal (longer radially, shorter axially)[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. This morphology is disadvantageous for spherical tumors, as the ablation zone may fail to provide sufficient margins to fully cover the target tumor. For tumors in unfavorable locations, the heat-sink effect may also lead to residual microscopic disease and microvascular invasion (MVI) escaping ablation, which is closely associated with LTP development[\u003cspan additionalcitationids=\"CR21 CR22\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Consequently, the efficacy at the superior/inferior margins and unfavorable locations may be underestimated during routine post-operative axial imaging evaluation. This explains why LTP in this study predominantly occurred at these sites. In summary, LTP lesions located at the superior/inferior margins or unfavorable positions, exhibiting arterial non-enhancement, portal/delayed phase washout, and a \"cloud-like\" enhancement morphology, present occult features on single-plane images and are more difficult to identify. In contrast, MPR technology leverages its advantage in displaying spatial relationships across multiple planes to enable earlier LTP detection.\u003c/p\u003e\u003cp\u003eThis study has several limitations. First, it is a single-center retrospective study with a limited sample size, potentially introducing selection bias. Second, the study spanned a considerable period during which operator experience and ablation technology itself may have evolved, potentially influencing outcomes. Third, follow-up imaging for some patients was relatively homogeneous, lacking supplementary MRI examinations. Radiomics, by extracting deep imaging features invisible to the naked eye and providing more specific, objective quantitative data, could offer a more precise evaluation of the ablation margin post-procedure. However, research utilizing radiomics for diagnosing post-ablation LTP is currently scarce. Future studies will focus on establishing a radiomics diagnostic model for LTP after liver cancer ablation through large-scale, multi-center efforts to achieve early diagnosis.\u003c/p\u003e\u003cp\u003eIn conclusion, the findings of this study indicate that follow-up strategies should be intensified, with a specific focus on evaluating the superior/inferior margins and unfavorable locations of the ablation zone. Axial multiphasic CE-CT combined with MPR technology significantly optimizes LTP diagnostic efficacy through multiplanar analysis, markedly improving sensitivity and enabling earlier diagnosis, particularly for lesions in occult locations. This provides high-level evidence for optimizing precise follow-up strategies after HCC ablation.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eAFP\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eAlpha fetoprotein\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eAM\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eAblation margin\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eCEUS\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eContrast-enhanced ultrasound\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eCT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eComputer tomography\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eHBV\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHepatitis B virus\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eHBV\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHepatitis C virus\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eHCC\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHepatocellular carcinoma\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eLTP\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eLocal tumor progression\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMDT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMultidisciplinary team\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMPR\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMulti-planar reconstruction\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMRI\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMagnetic resonance imaging\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMWA\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMicrowave ablation\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMVI\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMicrovascular invasion\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eTBIL\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eTotal bilirubin\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eZhu,Z.: research design, data collection, data organization,statistical analysis, and paper writing.\u003c/p\u003e\n\u003cp\u003eZhang,M.Y.: data collection, statistical analysis.\u003c/p\u003e\n\u003cp\u003eCai,F.C.: data collection, data organization\u003c/p\u003e\n\u003cp\u003eChen,W.X.: statistical analysis, data collection.\u003c/p\u003e\n\u003cp\u003eWu,Q.D.: research design, paper review, and research supervision.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eZhou,Y.Y.: paper review, and research supervision.\u003c/p\u003e\n\u003cp\u003eAll authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Ethics Committee of Shunde Hospital, Guangzhou University of Chinese Medicine (Approval No. KY-2024155) and conducted in accordance with the Declaration of Helsinki.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eInformed consent was waived by the Ethics Committee due to the retrospective nature of the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets analysed during the current study are not publicly available due to ethical restrictions but are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSingal AG, Llovet JM, Yarchoan M, Mehta N, Heimbach JK, Dawson LA, et al. AASLD Practice Guidance on prevention, diagnosis, and treatment of hepatocellular carcinoma. Hepatology. 2023;78(6):1922\u0026ndash;65. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/HEP.0000000000000466\u003c/span\u003e\u003cspan address=\"10.1097/HEP.0000000000000466\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEASL Clinical Practice Guidelines. Management of hepatocellular carcinoma. J Hepatol. 2018;69(1):182\u0026ndash;236. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jhep.2018.03.019\u003c/span\u003e\u003cspan address=\"10.1016/j.jhep.2018.03.019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDing WZ, Liu S, Liu F, Cheng Z, Yu X, Han ZY, et al. Are all local tumour progressions of HCC related to thermal ablation? A study of the causes and classification of local tumour progression. Eur Radiol. 2022;32(12):8518\u0026ndash;26. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00330-022-08913-1\u003c/span\u003e\u003cspan address=\"10.1007/s00330-022-08913-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePark MH, Rhim H, Kim YS, Choi D, Lim HK, Lee WJ. Spectrum of CT findings after radiofrequency ablation of hepatic tumors. Radiographics. 2008;28(2):379\u0026ndash;90. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1148/rg.282075038\u003c/span\u003e\u003cspan address=\"10.1148/rg.282075038\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. 390-2.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMinami Y, Nishida N, Kudo M, World. J Gastroentero. 2014;20(15):4160\u0026ndash;6. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3748/wjg.v20.i15.4160\u003c/span\u003e\u003cspan address=\"10.3748/wjg.v20.i15.4160\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLee MW, Kang D, Lim HK, Cho J, Sinn DH, Kang TW, et al. Updated 10-year outcomes of percutaneous radiofrequency ablation as first-line therapy for single hepatocellular carcinoma\u0026thinsp;\u0026lt;\u0026thinsp;3 cm: emphasis on association of local tumor progression and overall survival. Eur Radiol. 2020;30(4):2391\u0026ndash;400. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00330-019-06575-0\u003c/span\u003e\u003cspan address=\"10.1007/s00330-019-06575-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCao S, Lyu T, Fan Z, Guan H, Song L, Tong X, et al. Long-term outcome of percutaneous radiofrequency ablation for periportal hepatocellular carcinoma: tumor recurrence or progression, survival and clinical significance. Cancer Imaging. 2022;22(1):2. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s40644-021-00442-2\u003c/span\u003e\u003cspan address=\"10.1186/s40644-021-00442-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBaumler W, Wiggermann P, Lurken L, Dollinger M, Stroszczynski C, Beyer LP, et al. Early Detection of Local Tumor Progression after Irreversible Electroporation (IRE) of a Hepatocellular Carcinoma Using Gd-EOB-DTPA-Based MR Imaging at 3T. Cancers. 2021;13(7). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/cancers13071595\u003c/span\u003e\u003cspan address=\"10.3390/cancers13071595\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBaumler W, Beyer LP, Lurken L, Wiggermann P, Stroszczynski C, Dollinger M, et al. Detection of Incomplete Irreversible Electroporation (IRE) and Microwave Ablation (MWA) of Hepatocellular Carcinoma (HCC) Using Iodine Quantification in Dual Energy Computed Tomography (DECT). Diagnostics. 2022;12(4). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/diagnostics12040986\u003c/span\u003e\u003cspan address=\"10.3390/diagnostics12040986\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePark Y, Choi D, Rhim H, Kim YS, Lee JY, Chang I, et al. Central lower attenuating lesion in the ablation zone on immediate follow-up CT after percutaneous radiofrequency ablation for hepatocellular carcinoma: incidence and clinical significance. Eur J Radiol. 2010;75(3):391\u0026ndash;6. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.ejrad.2009.04.054\u003c/span\u003e\u003cspan address=\"10.1016/j.ejrad.2009.04.054\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKim YS, Lee WJ, Rhim H, Lim HK, Choi D, Lee JY. The minimal ablative margin of radiofrequency ablation of hepatocellular carcinoma (\u0026gt;\u0026thinsp;2 and \u0026lt;\u0026thinsp;5 cm) needed to prevent local tumor progression: 3D quantitative assessment using CT image fusion. Am J Roentgenol. 2010;195(3):758\u0026ndash;65. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2214/AJR.09.2954\u003c/span\u003e\u003cspan address=\"10.2214/AJR.09.2954\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLlovet JM, Lencioni R. mRECIST for HCC: Performance and novel refinements. J Hepatol. 2020;72(2):288\u0026ndash;306. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jhep.2019.09.026\u003c/span\u003e\u003cspan address=\"10.1016/j.jhep.2019.09.026\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLee SR, Kilcoyne A, Kambadakone A, Arellano R. Interventional oncology: pictorial review of post-ablation imaging of liver and renal tumors. Abdom Radiol. 2016;41(4):677\u0026ndash;705. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00261-016-0665-3\u003c/span\u003e\u003cspan address=\"10.1007/s00261-016-0665-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVandenbroucke F, Vandemeulebroucke J, Buls N, Thoeni RF, de Mey J. Can tumor coverage evaluated 24 h post-radiofrequency ablation predict local tumor progression of liver metastases? Int J Comput Ass Rad. 2018;13(12):1981\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s11548-018-1765-z\u003c/span\u003e\u003cspan address=\"10.1007/s11548-018-1765-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePaolucci I, Albuquerque MSJ, Lin YM, Shieh A, Ierardi AM, Caraffiello G, et al. Quantitative Ablation Confirmation Methods in Percutaneous Thermal Ablation of Malignant Liver Tumors: Technical Insights, Clinical Evidence, and Future Outlook. Radiol Imaging Cancer. 2025;7(3):e240293. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1148/rycan.240293\u003c/span\u003e\u003cspan address=\"10.1148/rycan.240293\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNakazawa T, Kokubu S, Shibuya A, Ono K, Watanabe M, Hidaka H, et al. Radiofrequency ablation of hepatocellular carcinoma: correlation between local tumor progression after ablation and ablative margin. Am J Roentgenol. 2007;188(2):480\u0026ndash;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2214/AJR.05.2079\u003c/span\u003e\u003cspan address=\"10.2214/AJR.05.2079\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTakeyama N, Mizobuchi N, Sakaki M, Shimozuma Y, Munechika J, Kajiwara A, et al. Evaluation of hepatocellular carcinoma ablative margins using fused pre- and post-ablation hepatobiliary phase images. Abdom Radiol. 2019;44(3):923\u0026ndash;35. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00261-018-1800-0\u003c/span\u003e\u003cspan address=\"10.1007/s00261-018-1800-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFarina L, Weiss N, Nissenbaum Y, Cavagnaro M, Lopresto V, Pinto R, et al. Characterisation of tissue shrinkage during microwave thermal ablation. Int J Hyperther. 2014;30(7):419\u0026ndash;28. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3109/02656736.2014.957250\u003c/span\u003e\u003cspan address=\"10.3109/02656736.2014.957250\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSimon CJ, Dupuy DE, Iannitti DA, Lu DS, Yu NC, Aswad BI, et al. Intraoperative triple antenna hepatic microwave ablation. Am J Roentgenol. 2006;187(4):W333\u0026ndash;40. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2214/AJR.05.0804\u003c/span\u003e\u003cspan address=\"10.2214/AJR.05.0804\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eImamura H, Matsuyama Y, Tanaka E, Ohkubo T, Hasegawa K, Miyagawa S, et al. Risk factors contributing to early and late phase intrahepatic recurrence of hepatocellular carcinoma after hepatectomy. J Hepatol. 2003;38(2):200\u0026ndash;7. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/s0168-8278(02)00360-4\u003c/span\u003e\u003cspan address=\"10.1016/s0168-8278(02)00360-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eErstad DJ, Tanabe KK. Prognostic and Therapeutic Implications of Microvascular Invasion in Hepatocellular Carcinoma. Ann Surg Oncol. 2019;26(5):1474\u0026ndash;93. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1245/s10434-019-07227-9\u003c/span\u003e\u003cspan address=\"10.1245/s10434-019-07227-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eXia T, Zhou Z, Meng X, Zha J, Yu Q, Wang W, et al. Predicting Microvascular Invasion in Hepatocellular Carcinoma Using CT-based Radiomics Model. Radiology. 2023;307(4):e222729. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1148/radiol.222729\u003c/span\u003e\u003cspan address=\"10.1148/radiol.222729\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePark Y, Choi D, Lim HK, Rhim H, Kim YS, Kim SH, et al. Growth rate of new hepatocellular carcinoma after percutaneous radiofrequency ablation: evaluation with multiphase CT. Am J Roentgenol. 2008;191(1):215\u0026ndash;20. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2214/AJR.07.3297\u003c/span\u003e\u003cspan address=\"10.2214/AJR.07.3297\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-medical-imaging","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmim","sideBox":"Learn more about [BMC Medical Imaging](http://bmcmedimaging.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bmim/default.aspx","title":"BMC Medical Imaging","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Microwave ablation, Computer Tomography, Local Tumour Progression","lastPublishedDoi":"10.21203/rs.3.rs-7295056/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7295056/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eObjective\u003c/h2\u003e\u003cp\u003eTo investigate early diagnosis feasibility and imaging manifestations of local tumour progression (LTP) after hepatocellular carcinoma (HCC) ablation.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eRetrospective analysis of 62 HCC patients (78 nodules) treated with microwave ablation. Two radiologists independently reviewed conventional axial and multiplanar reconstruction (MPR) images using a double-blind method to analyse early LTP features and diagnostic efficacy.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003ePostoperative LTP was diagnosed in 23/78 nodules. MPR significantly improved LTP detection sensitivity for both observers (0.65 vs. 0.96; P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Inter-observer agreement was excellent. LTP lesions at ablation zone superior/inferior margins, in unfavorable locations, or showing arterial non-enhancement with portal/delayed phase washout and \"cloud-like\" morphology were more occult. Median time to clinical LTP diagnosis was 16 months. With MPR assistance, observers diagnosed LTP earlier (median 15 months).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eMultiphasic CE-CT combined with MPR enables early diagnosis of LTP. This study describes the imaging characteristics of occult LTP lesions that are easily overlooked.\u003c/p\u003e","manuscriptTitle":"Multiplanar Reconstruction Improves Early Diagnosis of Occult Local Tumor Progression after Microwave Ablation for Hepatocellular Carcinoma","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-11 11:02:46","doi":"10.21203/rs.3.rs-7295056/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewersInvited","content":"","date":"2025-09-04T06:27:42+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-02T08:55:14+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-08-11T13:07:04+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-11T07:55:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Medical Imaging","date":"2025-08-11T07:52:00+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-medical-imaging","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmim","sideBox":"Learn more about [BMC Medical Imaging](http://bmcmedimaging.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bmim/default.aspx","title":"BMC Medical Imaging","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fd170ddb-9f8f-40a8-afeb-676490a06e52","owner":[],"postedDate":"September 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-09-11T11:02:46+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-11 11:02:46","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7295056","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7295056","identity":"rs-7295056","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}