Percutaneous Portal Venography vs. Contrast-Enhanced CT in Pediatric Extrahepatic Portal Vein Obstruction: A Comparative Study

Percutaneous Portal Venography vs. Contrast-Enhanced CT in Pediatric Extrahepatic Portal Vein Obstruction: A Comparative Study | 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 Percutaneous Portal Venography vs. Contrast-Enhanced CT in Pediatric Extrahepatic Portal Vein Obstruction: A Comparative Study Mert Bayramoglu, Evrim Özmen, Enes Muhammed Cantürk, Vugar Samadlı, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6701430/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Extrahepatic portal vein obstruction (EHPVO) is a major cause of portal hypertension in children. Imaging is essential for diagnosis and treatment planning. While CT is commonly used, it may miss patent intrahepatic branches. Percutaneous portal venography (PVG) offers more detailed vascular imaging but is invasive. Comparative studies between CT and PVG in pediatric EHPVO are limited Objectives To compare the effectiveness of contrast-enhanced computed tomography (CT) and percutaneous portal venography (PVG) in visualizing intrahepatic portal vein segments and various findings such as varices, shunts, and portal biliopathy in children with non-cirrhotic, non-malignant, chronic extrahepatic portal vein obstruction (EHPVO). Materials & Methods This retrospective single-center study included pediatric patients with EHPVO between 2018 and 2024. All patients underwent contrast-enhanced CT and PVG before attempted portal vein recanalization. Imaging findings were compared for intrahepatic portal vein visualization, cavernoma type, presence of varices and shunts, and portal biliopathy. Statistical analysis included McNemar's test, chi-square/Fisher’s exact test, and one-way ANOVA. Results This study included 18 pediatric patients (mean age, 7.0 ± 2.8 years; 12 males). PVG demonstrated significantly higher visualization rates of intrahepatic portal vein branches in segments 4–8 ( p = 0.013–0.035) compared to CT. CT failed to identify some branches that were patent on PVG. Cavernoma type showed no significant association with patient age or presence of portal biliopathy ( p > 0.05). Gallbladder and gastric varices were strongly associated and inversely related to splenorenal shunts ( p = 0.029). Conclusion CT and PVG are complementary tools in the management of pediatric EHPVO. While CT supports pre-procedural planning, PVG provides superior intrahepatic vascular detail and facilitates recanalization. However, the lack of predictive criteria for procedural success highlights the need for further research in patient selection. Portal vein thrombosis Extrahepatic portal vein obstruction Pediatric interventional radiology Portal venography Computed tomography Figures Figure 1 Figure 2 Introduction Non-cirrhotic, non-malignant, chronic extrahepatic portal vein obstruction (EHPVO) due to portal vein thrombosis (PVT) is a rare [ 1 , 2 ] but significant condition responsible for the majority of prehepatic portal hypertension cases in children [ 3 ], leading to severe complications such as variceal bleeding, splenomegaly, and hypersplenism. Timely diagnosis and effective treatment are essential to mitigate long-term complications, especially in pediatric patients. While surgical interventions like Meso-Rex bypass have been traditionally used in complicated cases, percutaneous recanalization has emerged as a minimally invasive alternative for selected patients [ 4 , 5 ]. Successful recanalization depends on accurate preprocedural imaging and intraprocedural guidance. Contrast-enhanced computed tomography (CT) is widely used for evaluating the portal venous system. It offers rapid acquisition and high spatial resolution, allowing for assessment of vascular patency, collateral circulation, and surrounding anatomical structures. Nevertheless, its ability to delineate intrahepatic portal branches can be limited, especially in cases with cavernomatous transformation. Percutaneous portal venography (PVG), performed via transhepatic or transsplenic access during interventional procedures, provides real-time dynamic visualization of vascular flow and architecture. PVG may reveal details that are not apparent on CT, particularly regarding small intrahepatic branches and hepatopetal flow patterns. Moreover, venography not only confirms the vascular anatomy but may also offer an opportunity for immediate recanalization through the same access route, further enhancing procedural efficiency and reducing the need for additional interventions. This study aimed to compare the visualization capabilities of CT and PVG in children with non-cirrhotic, non-malignant EHPVO. We specifically assessed their respective strengths in delineating intrahepatic portal anatomy and secondary findings such as portal cavernoma, varices, biliopathy, and portosystemic shunts. By evaluating both modalities in the same cohort, we sought to clarify their complementary roles and provide insight into optimal imaging strategies for planning percutaneous recanalization in pediatric EHPVO. Materials and Methods Study Design and Patients: This single-center, retrospective study was approved by the institutional review board. The requirement for informed consent was waived in accordance with the Declaration of Helsinki and relevant ethical regulations. This study included patients aged 0–18 years who were diagnosed with EHPVO in a native liver between 2018 and 2024. Patients with chronic, complete thrombotic occlusion of the main portal vein (PV) were included, regardless of whether the occlusion extended to the intrahepatic PV branches, the splenic vein (SV), or the superior mesenteric vein (SMV). Exclusion criteria were prior liver transplantation, missing/inadequate imaging, parenchymal PV occlusion with a patent main PV, malignant PV obstruction, and partial EHPVO. Data on radiographic studies were extracted and analyzed from the patients' records. CT Protocol: Preprocedural CT imaging was performed with a dual-source Siemens Somatom Definition Flash CT scanner (Siemens Healthcare). Patients were fasted for 6 hours before the examination. Opaxol (Iohexol 300 mg I/mL; Nycomed) was used as contrast material in both CT imaging and PVG procedures. Contrast injection rate for CT was between 2–3 mL/s depending on the access catheter size [ 6 ] and the contrast dose was 2 mL/kg. Scanning slice thickness was 1 mm. Constant tube voltage was 100 kvP and mAs values were automated according to the patient weight [ 7 ]. The ROI was placed in lower thoracic aorta and the full scan is started automatically once a predetermined threshold attenuation value of 150 Hounsfield Units (HU) is reached [ 8 ]. The scan consists of CT angiography in the arterial, portal, and hepatic venous phases. Portal and hepatic venous phase images were acquired at 20 s and 60 s following the arterial imaging. In addition to axial images, coronal and sagittal reformatted images were also generated and used for evaluation. No oral contrast was given. PVG Procedure: All percutaneous imaging procedures were performed with the aim of recanalizing the PV. The transhepatic and/or transsplenic PVG procedure was performed under general anesthesia, with transhepatic access to the peripheral PV and/or transsplenic access to the peripheral SV under the guidance of ultrasonography, following insertion using the AccuStick entry set (AccuStick II Introducer System; Boston Scientific) and placement of a 4F vascular sheath (Avanti, Cordis) under fluoroscopy guidance. 4F manipulation catheter (Tempo Aqua, Cordis) was placed in the appropriate position. Digital substraction angiography was performed with a total of 10 ml iodinated contrast material at 300 psi pressure and 4 mL/s injection rate. Following the procedure, the access tract was embolized using gelatin sponge pledgets (Gelfoam; Pfizer Inc.). Image Analysis: The diagnosis of EHPVO was confirmed by CT imaging. To determine procedural feasibility, CT images were evaluated for the patency of intrahepatic PV segments that can be percutaneously accessed, a patent SV with a configuration allowing access to the occluded segment, the patency of the SMV, cavernous transformation of the PV, portal biliopathy, esophageal, gastric and gallbladder varices and the presence of a splenorenal shunt. The same anatomical parameters were retrospectively evaluated on PVG images for comparison. Right, left, and intrahepatic PV branches were considered patent if clearly visualized on imaging; otherwise, they were considered occluded. PC morphology was classified into two types on PVG: Type 1, in which the hilar branches were individually visible, and Type 2, in which the branches were indistinct. This classification was performed using PVG [ 9 ]. Portal biliopathy, defined as biliary ductal dilatation due to cavernous compression, was evaluated only on CT, as it was not assessable by venography [ 10 ]. Main PV occlusion, SV and SMV patency, along with the presence of varices and shunts, were reliably visualized by both modalities and were therefore not statistically compared. Internal associations among these secondary findings were analyzed descriptively. All CT and DSA images were reviewed by an experienced pediatric radiologist (E.Ö.) and interventional radiologists (M.B., V.S., L.O.). Imaging-related decisions were made by consensus among the reviewers. Statistical Analysis: Statistical analyses were performed using SPSS (version 28). McNemar’s test was used to compare paired proportions of PV segment visualization between PVG and CT. The Chi-square test or Fisher’s exact test (for expected cell counts < 5) was applied to assess associations between categorical variables, including cavernoma type, presence of biliopathy, varices, and shunt. One-way ANOVA was used to compare patient age across different cavernoma types. Normality of age distribution within cavernoma subgroups was assessed using the Shapiro-Wilk test and confirmed for both groups. A p -value < 0.05 was considered statistically significant. Results A total of 51 pediatric patients diagnosed with EHPVO between 2018 and 2024 were evaluated. 24 patients (47,06%) were excluded due to EHPVO developing after liver transplantation, 3 patients (5,88%) were excluded due to having only transhepatic access with no adequate imaging, 2 patients (3,92%) were excluded due to partial EHPVO, and 4 patients (5,88%) were excluded due to the absence of pre-procedural CT imaging, 18 patients met the inclusion criteria (Fig. 1 ). The final cohort included 12 males and 6 females, with a median age of 7 years (range 2–12 years). Most patients (n = 12, 66%) had a history of umbilical vein catheterization as the primary etiology. Less common etiologies included umbilical infection (2 patients, 11%), MTHFR heterozygous mutation (1 patient, 5,5%), PAI gene mutations (1 patients, 5,5%), and 2 patients, 11% with no known etiology (Table 1 ). Table 1 Demographic and etiologic characteristics of the study population Characteristic Value Total Patients 18 Gender (male, female) 12 (66.7%), 6 (33.3%) Age, median (range) 7 years, (2–12) Umbilical Vein Catheterization 12 (66.7%) Umbilical Infection 2 (11.1%) MTHFR Heterozygous Mutation 1 (5.6%) PAI Gene Mutations 1 (5.6%) No Known Etiology 2 (11.1%) PVG was successfully performed in 15 patients (83.3%) via transsplenic access by positioning the catheter tip proximal to the stenosis. In the remaining 3 patients (16.6%), transhepatic access was utilized to traverse the stenotic region, with the catheter tip similarly positioned proximal to the stenosis for imaging. In both PVG and CT evaluations, no flow was detected in the main PV in any of the 18 patients (100%). One patient (5,5%) had an occluded SV, and one (5,5%) had an occluded SMV; in the remaining patients (89%), both the SV and SMV were patent. All relevant findings were similarly visualized by both imaging modalities. For the right and left PVs, PVG demonstrated a higher visualization rate (33.3%) than CT (22.2%), but the difference was not statistically significant ( p = 0.077 for both). In segment 2–3, PVG visualized 77.8% of cases compared to 61.1% for CT, the difference was not statistically significant ( p = 0.118). In segment 4, PVG visualized 83.3%, while CT visualized 66.7%, with the difference being statistically significant (p = 0.035). In segments 5, 6, 7, and 8, PVG consistently exhibited higher visualization rates (88.9%) compared to CT (69.4% in segments 5,6 and 8, and 66.7% in segment 7), and the differences were statistically significant ( p = 0.013 for all four segments) ( Table 2 ). Table 2 Visualization rates of PV segments by PVG and CT PV Segment PVG Visualization Rate (%) PVG Cases (n) CT Visualization Rate (%) CT Cases (n) p-value* Right PV 33,3 6 22,2 4 0.077 Left PV 33,3 6 22,2 4 0.077 Segment 2–3 77,8 14 61,1 11 0.118 Segment 4 83,3 15 66,7 12 0.035* Segment 5 88,9 16 69,4 13 0.013* Segment 6 88,9 16 69,4 13 0.013* Segment 7 88,9 16 66,7 12 0.013* Segment 8 88,9 16 69,4 13 0.013* * p-values < 0.05 are statistically significant and marked with an asterisk Type 1 cavernoma was observed in 11 out of 18 patients (61%) and type 2 cavernoma was observed in 7 out of 18 patients (39%). Gallbladder varices were observed in 9 out of 18 patients (50%). Esophageal varices were observed in 13 out of 18 patients (72%), these varices were gastroesophageal type in 9 out of 18 patients (50%). 5 out of 18 patients (28%) had prominent splenorenal shunts. 9 out of 18 patients (50%) had portal biliopathy ( Fig. 2 ). Splenic and mesenteric vein patency was confirmed in all patients using both CT and PVG, with complete agreement between modalities. There was no statistically significant difference in patient age between different types of cavernoma (one-way ANOVA, p > 0.05). No significant association was found between the type of cavernoma and the presence of portal biliopathy (Chi-square test, p > 0.05). All patients with gastric varices also had gall bladder varices (9/9, 100%). However, gall bladder varices were observed in 69% (9/13) of patients with esophageal varices. A statistically significant inverse association was found between the presence of gall bladder varices and splenorenal shunt (Fisher’s exact test, p = 0.029). A similar inverse relationship was observed for gastric varices ( p = 0.029), while no statistically significant association was detected for esophageal varices ( p = 0.099) Discussion Our results indicate that both imaging modalities are equally effective in detecting main PV occlusion as well as assessing the patency of the SV and SMV. During preprocedural evaluation, some right and left PV branches, as well as numerous intrahepatic branches that were clearly patent on PVG, were not visualized or were misinterpreted as occluded on CT, indicating that CT may underestimate PV patency. To our knowledge, no prior studies have directly compared CT and PVG in this setting. However, two studies have compared magnetic resonance (MR) imaging with PVG in the evaluation of EHPVO in pediatric patients. One study concluded that MR was insufficient for assessing intrahepatic PVs when compared to retrograde portography [ 11 ], while another study demonstrated that CO₂ PVG using an ultrafine needle was safer and more effective than MR portography and transarterial portography for visualizing these vessels [ 12 ]. These findings are consistent with our results, supporting the superiority of PVG in depicting intrahepatic PV anatomy. Beyond the primary imaging findings, our study also evaluated several additional features of EHPVO. We used Zhang et al.’s classification of portal cavernoma, but unlike their results, we found no significant correlation between cavernoma type and patient age [ 13 ]. PC was present in all patients, with no significant association between its morphological type and the presence of portal biliopathy. Variceal patterns were heterogeneous: while esophageal varices were the most common, gastric and gallbladder varices often coexisted and showed strong interdependence. The presence of spontaneous splenorenal shunts appeared to inversely correlate with the formation of gastric and gallbladder varices, implying a possible protective role through decompression of portal pressure [ 14 ]. Non-invasive imaging of the portal venous system in pediatric EHPVO is difficult due to narrow vessel calibers and the complex vascular alterations caused by cavernous transformation [ 15 ]. In this context, non-invasive imaging alone does not provide enough information to assess the feasibility or potential benefit of surgical or percutaneous interventions [ 16 – 21 ]. Wedged hepatic vein portography is a minimally invasive alternative for PV imaging [ 19 ]. However, as an interventional technique, it may be limited in delineating the overall portal venous anatomy, (SV), mesenteric veins, varices, and shunts. It does not provide information on flow dynamics and lacks therapeutic capability [ 22 ]. PVG, once regarded with caution due to safety concerns, has become a safe and well-established procedure with the advancement of interventional techniques [ 23 – 26 ]. PVG is particularly valuable for visualizing the architecture of the highly complex PC, which may develop as early as 5–20 days after EHPVO, and for identifying potential hepatopetal pathways, owing to its dynamic imaging capabilities [ 13 , 27 – 29 ]. It provides detailed panoramic visualization of the entire portal venous system, enables assessment of flow direction and velocity, and permits direct measurement of PV pressure. Importantly, it can identify various varices and spontaneous portosystemic shunts that develop secondary to portal hypertension. Furthermore, once vascular access is obtained, therapeutic interventions such as variceal embolization [ 30 ], and PV recanalization can also be performed in the same session. Another advantage of this approach is that, even if these procedures do not yield the desired outcome, they do not pose an obstacle to performing subsequent Meso-Rex bypass surgery [ 31 ]. Despite CT's limitations in visualizing intrahepatic portal veins, it remains crucial for pre-procedural assessment, as it not only confirms the diagnosis of EHPVO and helps exclude other pathologies such as malignancy, but also provides detailed visualization of the SV, SMV, gastric and esophageal varices, portal biliopathy, and the presence of splenorenal shunts. This detailed anatomical information enhances the success of portal recanalization procedures and minimizes potential complications. Therefore, a non-invasive imaging modality should be employed prior to each portal recanalization or surgical procedure to clearly delineate the anatomical details and potential pathologies of the portal venous system. While noninvasive modalities such as ultrasound, CT, and MRI each offer unique advantages and limitations, we prefer CT due to its superior spatial resolution, rapid acquisition time, and ability to provide essential anatomical insight for safe and effective intervention planning [ 18 , 32 , 33 ]. Despite recent advances in imaging and intervention, the suitability and long-term success of Meso-Rex bypass surgery remain highly variable across patients. In parallel, there are currently no established imaging or clinical criteria to reliably predict which pediatric patients will benefit from percutaneous PV recanalization [ 31 ]. This uncertainty underscores the need for further prospective studies to better define patient selection and support individualized treatment planning in EHPVO. PVG and CT are both effective in confirming main PV occlusion in pediatric EHPVO. CT remains essential for pre-procedural planning due to its ability to assess vascular circulation and abdominal anatomy. However, its inability to visualize intrahepatic portal vein branches despite their patency may discourage the operator from attempting an intervention. PVG provides superior visualization of intrahepatic PV branches, detailed mapping of portal cavernoma architecture, and assessment of hepatopetal flow pathways, spontaneous portosystemic shunts, and various variceal patterns, which may influence treatment strategy. Nevertheless, the lack of reliable predictors for recanalization success remains a clinical challenge, and further studies are warranted to guide decision-making and optimize outcomes. Abbreviations CT : Computed Tomography DSA : Digital Subtraction Angiography EHPVO : Extrahepatic Portal Vein Obstruction MR : Magnetic Resonance / Magnetic Resonance Imaging PC : Portal Cavernoma PVG : Portal Venography Declarations This study received approval from the Institutional Review Board for Biomedical Research (approval number withheld for blinded review). The requirement for informed consent was waived due to the retrospective study design. Funding: The authors received no financial support for this study. Competing Interests: The authors declare that they have no competing interests. Consent to Participate: The requirement for informed consent was waived by the institutional review board due to the retrospective nature of the study. Consent to Publish: No identifying information or images of individual participants are included in this article. Therefore, consent for publication was not required. Data/Materials Availability: The datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request. All authors contributed to the study conception and design. Data collection, image analysis, and interpretation were performed by the study investigators. The first draft of the manuscript was written by one of the authors, and all authors commented on previous versions. All authors read and approved the final manuscript. References Morag I, Epelman M, Daneman A, et al (2006) Portal vein thrombosis in the neonate: Risk factors, course, and outcome. J Pediatr 148:735–739. https://doi.org/https://doi.org/10.1016/j.jpeds.2006.01.051 Heller C, Schobess R, Kurnik K, et al (2000) Abdominal venous thrombosis in neonates and infants: role of prothrombotic risk factors – a multicentre case–control study. 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Eur Radiol. https://doi.org/10.1007/s00330-024-11040-8 Marra P, Dulcetta L, Carbone FS, et al (2022) The Role of Imaging in Portal Vein Thrombosis: From the Diagnosis to the Interventional Radiological Management. Diagnostics 12:. https://doi.org/10.3390/diagnostics12112628 Corness JAG, McHugh K, Roebuck DJ, Taylor AM (2006) The portal vein in children: Radiological review of congenital anomalies and acquired abnormalities. Pediatr Radiol 36:87–96 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. 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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-6701430","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":463066032,"identity":"69cdec9e-3499-4086-90e6-eacf4c1f494b","order_by":0,"name":"Mert Bayramoglu","email":"","orcid":"","institution":"Koç University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Mert","middleName":"","lastName":"Bayramoglu","suffix":""},{"id":463066033,"identity":"efdbc773-013a-4cae-be07-e82beb8101ac","order_by":1,"name":"Evrim Özmen","email":"","orcid":"","institution":"Koç University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Evrim","middleName":"","lastName":"Özmen","suffix":""},{"id":463066034,"identity":"f68017c5-0dc8-4d9c-8a17-18ea468d00f4","order_by":2,"name":"Enes Muhammed Cantürk","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA30lEQVRIie3OsQrCMBCA4QNBl0jXc/EZTgpxUOirBARdOghC8QnqEvBZXDo5tBR0OXXtJAWhk0NdnI3ioKC1o0P+JeHIRw7AZvvjyBHQBIjvd1XjvXlIHf1K4jqEuC5xWmlxuoRH12WWOXBqJj41LuvvpKPHfUrCmZQ73SfIUjM5E8TFd0IZSExCNZQHIRHK1Ex8Qyo287LW9UHc5ZN4vwihePwiqa0NMYsR/iDIfoC8Vy7yJkDFE4FcTGOuIM5iG+E8UL2lHkVYbgZdZzFa5fMK8p4CEPezNrDZbDbb524WkVOFLebtyQAAAABJRU5ErkJggg==","orcid":"","institution":"Koç University Hospital","correspondingAuthor":true,"prefix":"","firstName":"Enes","middleName":"Muhammed","lastName":"Cantürk","suffix":""},{"id":463066035,"identity":"58d84541-546d-40fc-9d40-6c5bbfd27e3f","order_by":3,"name":"Vugar Samadlı","email":"","orcid":"","institution":"Koç University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Vugar","middleName":"","lastName":"Samadlı","suffix":""},{"id":463066036,"identity":"9a27b700-284e-45e3-b853-c443fc18c483","order_by":4,"name":"Levent Oguzkurt","email":"","orcid":"","institution":"Koç University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Levent","middleName":"","lastName":"Oguzkurt","suffix":""}],"badges":[],"createdAt":"2025-05-19 18:38:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6701430/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6701430/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83681370,"identity":"77674b41-f0cc-4789-a133-beb4a1c09d5a","added_by":"auto","created_at":"2025-05-30 16:13:26","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":201251,"visible":true,"origin":"","legend":"\u003cp\u003ePatient inclusion and exclusion flowchart for EHPVO study\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6701430/v1/0f39e7fb32ec03a02860a2e5.png"},{"id":83681373,"identity":"60b70df3-b7e3-4770-a9db-d128a79d21f0","added_by":"auto","created_at":"2025-05-30 16:13:26","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1028757,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative PVG and CT images in a pediatric EHPVO patient.\u003cbr\u003e\n \u003cstrong\u003e(a–c)\u003c/strong\u003e Sequential anterior-posterior plane PVG images from the same patient demonstrate the dynamic nature of venography: (a) panoramic view of the portal venous system; (b) large collateral vessels feeding the PC (white arrow) and gastric varices (white star); (c) delayed-phase image showing gallbladder varices (black arrow) and intrahepatic PV filling.\u003cbr\u003e\n \u003cstrong\u003e(d)\u003c/strong\u003e Coronal reformatted portal phase CT showing mild portal biliopathy (black arrow) which cannot be evaluated with PVG. The collateral vessel at portal hilum may be misinterpreted as a patent PV.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6701430/v1/0d002a003c7a06c0ee2bbc2a.png"},{"id":87771467,"identity":"1e85802e-d24b-4e47-95f3-19377c221c1c","added_by":"auto","created_at":"2025-07-28 20:01:31","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2476511,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6701430/v1/bc8c57c4-1801-4945-a18c-afe969a695a2.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003ePercutaneous Portal Venography vs. Contrast-Enhanced CT in Pediatric Extrahepatic Portal Vein Obstruction: A Comparative Study\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eNon-cirrhotic, non-malignant, chronic extrahepatic portal vein obstruction (EHPVO) due to portal vein thrombosis (PVT) is a rare [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] but significant condition responsible for the majority of prehepatic portal hypertension cases in children [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], leading to severe complications such as variceal bleeding, splenomegaly, and hypersplenism. Timely diagnosis and effective treatment are essential to mitigate long-term complications, especially in pediatric patients.\u003c/p\u003e \u003cp\u003eWhile surgical interventions like Meso-Rex bypass have been traditionally used in complicated cases, percutaneous recanalization has emerged as a minimally invasive alternative for selected patients [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Successful recanalization depends on accurate preprocedural imaging and intraprocedural guidance.\u003c/p\u003e \u003cp\u003eContrast-enhanced computed tomography (CT) is widely used for evaluating the portal venous system. It offers rapid acquisition and high spatial resolution, allowing for assessment of vascular patency, collateral circulation, and surrounding anatomical structures. Nevertheless, its ability to delineate intrahepatic portal branches can be limited, especially in cases with cavernomatous transformation.\u003c/p\u003e \u003cp\u003ePercutaneous portal venography (PVG), performed via transhepatic or transsplenic access during interventional procedures, provides real-time dynamic visualization of vascular flow and architecture. PVG may reveal details that are not apparent on CT, particularly regarding small intrahepatic branches and hepatopetal flow patterns. Moreover, venography not only confirms the vascular anatomy but may also offer an opportunity for immediate recanalization through the same access route, further enhancing procedural efficiency and reducing the need for additional interventions.\u003c/p\u003e \u003cp\u003eThis study aimed to compare the visualization capabilities of CT and PVG in children with non-cirrhotic, non-malignant EHPVO. We specifically assessed their respective strengths in delineating intrahepatic portal anatomy and secondary findings such as portal cavernoma, varices, biliopathy, and portosystemic shunts. By evaluating both modalities in the same cohort, we sought to clarify their complementary roles and provide insight into optimal imaging strategies for planning percutaneous recanalization in pediatric EHPVO.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e Study Design and Patients: This single-center, retrospective study was approved by the institutional review board. The requirement for informed consent was waived in accordance with the Declaration of Helsinki and relevant ethical regulations.\u003c/p\u003e \u003cp\u003eThis study included patients aged 0\u0026ndash;18 years who were diagnosed with EHPVO in a native liver between 2018 and 2024. Patients with chronic, complete thrombotic occlusion of the main portal vein (PV) were included, regardless of whether the occlusion extended to the intrahepatic PV branches, the splenic vein (SV), or the superior mesenteric vein (SMV). Exclusion criteria were prior liver transplantation, missing/inadequate imaging, parenchymal PV occlusion with a patent main PV, malignant PV obstruction, and partial EHPVO. Data on radiographic studies were extracted and analyzed from the patients' records.\u003c/p\u003e \u003cp\u003eCT Protocol: Preprocedural CT imaging was performed with a dual-source Siemens Somatom Definition Flash CT scanner (Siemens Healthcare). Patients were fasted for 6 hours before the examination. Opaxol (Iohexol 300 mg I/mL; Nycomed) was used as contrast material in both CT imaging and PVG procedures. Contrast injection rate for CT was between 2\u0026ndash;3 mL/s depending on the access catheter size [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] and the contrast dose was 2 mL/kg. Scanning slice thickness was 1 mm. Constant tube voltage was 100 kvP and mAs values were automated according to the patient weight [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The ROI was placed in lower thoracic aorta and the full scan is started automatically once a predetermined threshold attenuation value of 150 Hounsfield Units (HU) is reached [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The scan consists of CT angiography in the arterial, portal, and hepatic venous phases. Portal and hepatic venous phase images were acquired at 20 s and 60 s following the arterial imaging. In addition to axial images, coronal and sagittal reformatted images were also generated and used for evaluation. No oral contrast was given.\u003c/p\u003e \u003cp\u003ePVG Procedure: All percutaneous imaging procedures were performed with the aim of recanalizing the PV. The transhepatic and/or transsplenic PVG procedure was performed under general anesthesia, with transhepatic access to the peripheral PV and/or transsplenic access to the peripheral SV under the guidance of ultrasonography, following insertion using the AccuStick entry set (AccuStick II Introducer System; Boston Scientific) and placement of a 4F vascular sheath (Avanti, Cordis) under fluoroscopy guidance. 4F manipulation catheter (Tempo Aqua, Cordis) was placed in the appropriate position. Digital substraction angiography was performed with a total of 10 ml iodinated contrast material at 300 psi pressure and 4 mL/s injection rate. Following the procedure, the access tract was embolized using gelatin sponge pledgets (Gelfoam; Pfizer Inc.).\u003c/p\u003e \u003cp\u003eImage Analysis: The diagnosis of EHPVO was confirmed by CT imaging. To determine procedural feasibility, CT images were evaluated for the patency of intrahepatic PV segments that can be percutaneously accessed, a patent SV with a configuration allowing access to the occluded segment, the patency of the SMV, cavernous transformation of the PV, portal biliopathy, esophageal, gastric and gallbladder varices and the presence of a splenorenal shunt. The same anatomical parameters were retrospectively evaluated on PVG images for comparison.\u003c/p\u003e \u003cp\u003eRight, left, and intrahepatic PV branches were considered patent if clearly visualized on imaging; otherwise, they were considered occluded. PC morphology was classified into two types on PVG: Type 1, in which the hilar branches were individually visible, and Type 2, in which the branches were indistinct. This classification was performed using PVG [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Portal biliopathy, defined as biliary ductal dilatation due to cavernous compression, was evaluated only on CT, as it was not assessable by venography [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Main PV occlusion, SV and SMV patency, along with the presence of varices and shunts, were reliably visualized by both modalities and were therefore not statistically compared. Internal associations among these secondary findings were analyzed descriptively.\u003c/p\u003e \u003cp\u003eAll CT and DSA images were reviewed by an experienced pediatric radiologist (E.\u0026Ouml;.) and interventional radiologists (M.B., V.S., L.O.). Imaging-related decisions were made by consensus among the reviewers.\u003c/p\u003e \u003cp\u003eStatistical Analysis: Statistical analyses were performed using SPSS (version 28). McNemar\u0026rsquo;s test was used to compare paired proportions of PV segment visualization between PVG and CT. The Chi-square test or Fisher\u0026rsquo;s exact test (for expected cell counts\u0026thinsp;\u0026lt;\u0026thinsp;5) was applied to assess associations between categorical variables, including cavernoma type, presence of biliopathy, varices, and shunt. One-way ANOVA was used to compare patient age across different cavernoma types. Normality of age distribution within cavernoma subgroups was assessed using the Shapiro-Wilk test and confirmed for both groups. A \u003cem\u003ep\u003c/em\u003e-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 51 pediatric patients diagnosed with EHPVO between 2018 and 2024 were evaluated. 24 patients (47,06%) were excluded due to EHPVO developing after liver transplantation, 3 patients (5,88%) were excluded due to having only transhepatic access with no adequate imaging, 2 patients (3,92%) were excluded due to partial EHPVO, and 4 patients (5,88%) were excluded due to the absence of pre-procedural CT imaging, 18 patients met the inclusion criteria (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe final cohort included 12 males and 6 females, with a median age of 7 years (range 2\u0026ndash;12 years). Most patients (n\u0026thinsp;=\u0026thinsp;12, 66%) had a history of umbilical vein catheterization as the primary etiology. Less common etiologies included umbilical infection (2 patients, 11%), MTHFR heterozygous mutation (1 patient, 5,5%), PAI gene mutations (1 patients, 5,5%), and 2 patients, 11% with no known etiology (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e).\u003c/b\u003e\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 \u003cp\u003eDemographic and etiologic characteristics of the study population\u003c/p\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\" colname=\"c1\"\u003e \u003cp\u003eCharacteristic\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eValue\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal Patients\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender (male, female)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (66.7%), 6 (33.3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge, median (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 years, (2\u0026ndash;12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUmbilical Vein Catheterization\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (66.7%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUmbilical Infection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (11.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMTHFR Heterozygous Mutation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (5.6%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePAI Gene Mutations\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (5.6%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo Known Etiology\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (11.1%)\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\u003ePVG was successfully performed in 15 patients (83.3%) via transsplenic access by positioning the catheter tip proximal to the stenosis. In the remaining 3 patients (16.6%), transhepatic access was utilized to traverse the stenotic region, with the catheter tip similarly positioned proximal to the stenosis for imaging.\u003c/p\u003e \u003cp\u003eIn both PVG and CT evaluations, no flow was detected in the main PV in any of the 18 patients (100%). One patient (5,5%) had an occluded SV, and one (5,5%) had an occluded SMV; in the remaining patients (89%), both the SV and SMV were patent. All relevant findings were similarly visualized by both imaging modalities.\u003c/p\u003e \u003cp\u003eFor the right and left PVs, PVG demonstrated a higher visualization rate (33.3%) than CT (22.2%), but the difference was not statistically significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.077 for both). In segment 2\u0026ndash;3, PVG visualized 77.8% of cases compared to 61.1% for CT, the difference was not statistically significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.118). In segment 4, PVG visualized 83.3%, while CT visualized 66.7%, with the difference being statistically significant (p\u0026thinsp;=\u0026thinsp;0.035). In segments 5, 6, 7, and 8, PVG consistently exhibited higher visualization rates (88.9%) compared to CT (69.4% in segments 5,6 and 8, and 66.7% in segment 7), and the differences were statistically significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.013 for all four segments) \u003cb\u003e(\u003c/b\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e).\u003c/b\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 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eVisualization rates of PV segments by PVG and CT\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=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePV Segment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePVG Visualization Rate (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePVG Cases (n)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCT Visualization Rate (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCT Cases (n)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ep-value*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRight PV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e33,3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22,2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.077\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLeft PV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e33,3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22,2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.077\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSegment 2\u0026ndash;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e77,8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e61,1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.118\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSegment 4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e83,3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e66,7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0.035*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSegment 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e88,9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e69,4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0.013*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSegment 6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e88,9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e69,4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0.013*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSegment 7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e88,9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e66,7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0.013*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSegment 8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e88,9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e69,4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0.013*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e* p-values\u0026thinsp;\u0026lt;\u0026thinsp;0.05 are statistically significant and marked with an asterisk\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eType 1 cavernoma was observed in 11 out of 18 patients (61%) and type 2 cavernoma was observed in 7 out of 18 patients (39%). Gallbladder varices were observed in 9 out of 18 patients (50%). Esophageal varices were observed in 13 out of 18 patients (72%), these varices were gastroesophageal type in 9 out of 18 patients (50%). 5 out of 18 patients (28%) had prominent splenorenal shunts. 9 out of 18 patients (50%) had portal biliopathy \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e).\u003c/b\u003e Splenic and mesenteric vein patency was confirmed in all patients using both CT and PVG, with complete agreement between modalities.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThere was no statistically significant difference in patient age between different types of cavernoma (one-way ANOVA, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). No significant association was found between the type of cavernoma and the presence of portal biliopathy (Chi-square test, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eAll patients with gastric varices also had gall bladder varices (9/9, 100%). However, gall bladder varices were observed in 69% (9/13) of patients with esophageal varices. A statistically significant inverse association was found between the presence of gall bladder varices and splenorenal shunt (Fisher\u0026rsquo;s exact test, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.029). A similar inverse relationship was observed for gastric varices (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.029), while no statistically significant association was detected for esophageal varices (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.099)\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eOur results indicate that both imaging modalities are equally effective in detecting main PV occlusion as well as assessing the patency of the SV and SMV. During preprocedural evaluation, some right and left PV branches, as well as numerous intrahepatic branches that were clearly patent on PVG, were not visualized or were misinterpreted as occluded on CT, indicating that CT may underestimate PV patency.\u003c/p\u003e \u003cp\u003eTo our knowledge, no prior studies have directly compared CT and PVG in this setting. However, two studies have compared magnetic resonance (MR) imaging with PVG in the evaluation of EHPVO in pediatric patients. One study concluded that MR was insufficient for assessing intrahepatic PVs when compared to retrograde portography [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], while another study demonstrated that CO₂ PVG using an ultrafine needle was safer and more effective than MR portography and transarterial portography for visualizing these vessels [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. These findings are consistent with our results, supporting the superiority of PVG in depicting intrahepatic PV anatomy.\u003c/p\u003e \u003cp\u003eBeyond the primary imaging findings, our study also evaluated several additional features of EHPVO. We used Zhang et al.\u0026rsquo;s classification of portal cavernoma, but unlike their results, we found no significant correlation between cavernoma type and patient age [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. PC was present in all patients, with no significant association between its morphological type and the presence of portal biliopathy. Variceal patterns were heterogeneous: while esophageal varices were the most common, gastric and gallbladder varices often coexisted and showed strong interdependence. The presence of spontaneous splenorenal shunts appeared to inversely correlate with the formation of gastric and gallbladder varices, implying a possible protective role through decompression of portal pressure [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eNon-invasive imaging of the portal venous system in pediatric EHPVO is difficult due to narrow vessel calibers and the complex vascular alterations caused by cavernous transformation [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In this context, non-invasive imaging alone does not provide enough information to assess the feasibility or potential benefit of surgical or percutaneous interventions [\u003cspan additionalcitationids=\"CR17 CR18 CR19 CR20\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWedged hepatic vein portography is a minimally invasive alternative for PV imaging [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. However, as an interventional technique, it may be limited in delineating the overall portal venous anatomy, (SV), mesenteric veins, varices, and shunts. It does not provide information on flow dynamics and lacks therapeutic capability [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePVG, once regarded with caution due to safety concerns, has become a safe and well-established procedure with the advancement of interventional techniques [\u003cspan additionalcitationids=\"CR24 CR25\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. PVG is particularly valuable for visualizing the architecture of the highly complex PC, which may develop as early as 5\u0026ndash;20 days after EHPVO, and for identifying potential hepatopetal pathways, owing to its dynamic imaging capabilities [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. It provides detailed panoramic visualization of the entire portal venous system, enables assessment of flow direction and velocity, and permits direct measurement of PV pressure. Importantly, it can identify various varices and spontaneous portosystemic shunts that develop secondary to portal hypertension. Furthermore, once vascular access is obtained, therapeutic interventions such as variceal embolization [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e], and PV recanalization can also be performed in the same session. Another advantage of this approach is that, even if these procedures do not yield the desired outcome, they do not pose an obstacle to performing subsequent Meso-Rex bypass surgery [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDespite CT's limitations in visualizing intrahepatic portal veins, it remains crucial for pre-procedural assessment, as it not only confirms the diagnosis of EHPVO and helps exclude other pathologies such as malignancy, but also provides detailed visualization of the SV, SMV, gastric and esophageal varices, portal biliopathy, and the presence of splenorenal shunts. This detailed anatomical information enhances the success of portal recanalization procedures and minimizes potential complications. Therefore, a non-invasive imaging modality should be employed prior to each portal recanalization or surgical procedure to clearly delineate the anatomical details and potential pathologies of the portal venous system. While noninvasive modalities such as ultrasound, CT, and MRI each offer unique advantages and limitations, we prefer CT due to its superior spatial resolution, rapid acquisition time, and ability to provide essential anatomical insight for safe and effective intervention planning [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDespite recent advances in imaging and intervention, the suitability and long-term success of Meso-Rex bypass surgery remain highly variable across patients. In parallel, there are currently no established imaging or clinical criteria to reliably predict which pediatric patients will benefit from percutaneous PV recanalization [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. This uncertainty underscores the need for further prospective studies to better define patient selection and support individualized treatment planning in EHPVO.\u003c/p\u003e \u003cp\u003ePVG and CT are both effective in confirming main PV occlusion in pediatric EHPVO. CT remains essential for pre-procedural planning due to its ability to assess vascular circulation and abdominal anatomy. However, its inability to visualize intrahepatic portal vein branches despite their patency may discourage the operator from attempting an intervention. PVG provides superior visualization of intrahepatic PV branches, detailed mapping of portal cavernoma architecture, and assessment of hepatopetal flow pathways, spontaneous portosystemic shunts, and various variceal patterns, which may influence treatment strategy. Nevertheless, the lack of reliable predictors for recanalization success remains a clinical challenge, and further studies are warranted to guide decision-making and optimize outcomes.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eCT : Computed Tomography\u003c/p\u003e\n\u003cp\u003eDSA : Digital Subtraction Angiography\u003c/p\u003e\n\u003cp\u003eEHPVO : Extrahepatic Portal Vein Obstruction\u003c/p\u003e\n\u003cp\u003eMR : Magnetic Resonance / Magnetic Resonance Imaging\u003c/p\u003e\n\u003cp\u003ePC : Portal Cavernoma\u003c/p\u003e\n\u003cp\u003ePVG : Portal Venography\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eThis study received approval from the Institutional Review Board for Biomedical Research (approval number withheld for blinded review). The requirement for informed consent was waived due to the retrospective study design.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Funding: The authors received no financial support for this study.\u003c/p\u003e\n\u003cp\u003eCompeting\u0026nbsp;Interests:\u0026nbsp;The\u0026nbsp;authors\u0026nbsp;declare\u0026nbsp;that\u0026nbsp;they\u0026nbsp;have\u0026nbsp;no\u0026nbsp;competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate:\u0026nbsp;\u003c/strong\u003eThe requirement for informed consent was waived by the institutional review board due to the retrospective nature of the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Publish:\u0026nbsp;\u003c/strong\u003eNo identifying information or images of individual participants are included in this article. Therefore, consent for publication was not required.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData/Materials Availability:\u0026nbsp;\u003c/strong\u003eThe datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Data collection, image analysis, and interpretation were performed by the study investigators. The first draft of the manuscript was written by one of the authors, and all authors commented on previous versions. All authors read and approved the final manuscript.\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMorag I, Epelman M, Daneman A, et al (2006) Portal vein thrombosis in the neonate: Risk factors, course, and outcome. J Pediatr 148:735\u0026ndash;739. https://doi.org/https://doi.org/10.1016/j.jpeds.2006.01.051\u003c/li\u003e\n\u003cli\u003eHeller C, Schobess R, Kurnik K, et al (2000) Abdominal venous thrombosis in neonates and infants: role of prothrombotic risk factors \u0026ndash; a multicentre case\u0026ndash;control study. Br J Haematol 111:534\u0026ndash;539. https://doi.org/https://doi.org/10.1111/j.1365-2141.2000.02349.x\u003c/li\u003e\n\u003cli\u003eSarin SK, Sollano JD, Chawla YK, et al (2006) Consensus on extra-hepatic portal vein obstruction. Liver International 26:512\u0026ndash;519. https://doi.org/https://doi.org/10.1111/j.1478-3231.2006.01269.x\u003c/li\u003e\n\u003cli\u003eYoung Shankar VR (2018) Management of Portal Hypertension in the Pediatric Population: A Primer for the Interventional Radiologist. Semin Intervent Radiol 35:160\u0026ndash;164. https://doi.org/10.1055/s-0038-1660794\u003c/li\u003e\n\u003cli\u003ede Franchis R, Bosch J, Garcia-Tsao G, et al (2022) Baveno VII \u0026ndash; Renewing consensus in portal hypertension. J Hepatol 76:959\u0026ndash;974. https://doi.org/https://doi.org/10.1016/j.jhep.2021.12.022\u003c/li\u003e\n\u003cli\u003eYekeler E (2004) Pediatric abdominal applications of multidetector-row CT. Eur J Radiol 52:31\u0026ndash;43. https://doi.org/10.1016/j.ejrad.2004.03.031\u003c/li\u003e\n\u003cli\u003eZacharias C, Alessio AM, Otto RK, et al (2013) Pediatric CT: Strategies to Lower Radiation Dose. American Journal of Roentgenology 200:950\u0026ndash;956. https://doi.org/10.2214/AJR.12.9026\u003c/li\u003e\n\u003cli\u003eCademartiri F, van der Lugt A, Luccichenti G, et al (2002) Parameters Affecting Bolus Geometry in CTA: A Review. J Comput Assist Tomogr 26:\u003c/li\u003e\n\u003cli\u003eZhang JS, Li L (2020) Imaging features and clinical relevance of portal venous systems shown by extrahepatic portal angiography in children with extrahepatic portal venous obstruction. J Vasc Surg Venous Lymphat Disord 8:756\u0026ndash;761. https://doi.org/10.1016/j.jvsv.2019.11.016\u003c/li\u003e\n\u003cli\u003eSarma M Sen, Ravindranath A (2020) Portal cavernoma cholangiopathy in children and the management dilemmas. J Clin Transl Hepatol 8:61\u0026ndash;68\u003c/li\u003e\n\u003cli\u003eKathemann S, Lainka E, Ludwig JM, et al (2019) Imaging of the intrahepatic portal vein in children with extrahepatic portal vein thrombosis \u0026mdash; Comparison of magnetic resonance imaging and retrograde portography. J Pediatr Surg 54:1686\u0026ndash;1690. https://doi.org/10.1016/j.jpedsurg.2018.10.049\u003c/li\u003e\n\u003cli\u003eTeng G-J, Deng G, Liu Z-S, et al (2006) Ultrafine needle CO2 splenoportography: A comparative investigation with transarterial portography and MR portography. Eur J Radiol 59:393\u0026ndash;400. https://doi.org/https://doi.org/10.1016/j.ejrad.2006.03.006\u003c/li\u003e\n\u003cli\u003eZhang JS, Li L (2020) Imaging features and clinical relevance of portal venous systems shown by extrahepatic portal angiography in children with extrahepatic portal venous obstruction. J Vasc Surg Venous Lymphat Disord 8:756\u0026ndash;761. https://doi.org/10.1016/j.jvsv.2019.11.016\u003c/li\u003e\n\u003cli\u003eProcopet B, Berzigotti A (2017) Diagnosis of cirrhosis \u0026amp; portal hypertension: Imaging, non-invasive markers of fibrosis \u0026amp; liver biopsy. 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Eur Radiol. https://doi.org/10.1007/s00330-024-11040-8\u003c/li\u003e\n\u003cli\u003eMarra P, Dulcetta L, Carbone FS, et al (2022) The Role of Imaging in Portal Vein Thrombosis: From the Diagnosis to the Interventional Radiological Management. Diagnostics 12:. https://doi.org/10.3390/diagnostics12112628\u003c/li\u003e\n\u003cli\u003eCorness JAG, McHugh K, Roebuck DJ, Taylor AM (2006) The portal vein in children: Radiological review of congenital anomalies and acquired abnormalities. Pediatr Radiol 36:87\u0026ndash;96\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Portal vein thrombosis, Extrahepatic portal vein obstruction, Pediatric interventional radiology, Portal venography, Computed tomography","lastPublishedDoi":"10.21203/rs.3.rs-6701430/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6701430/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eExtrahepatic portal vein obstruction (EHPVO) is a major cause of portal hypertension in children. Imaging is essential for diagnosis and treatment planning. While CT is commonly used, it may miss patent intrahepatic branches. Percutaneous portal venography (PVG) offers more detailed vascular imaging but is invasive. Comparative studies between CT and PVG in pediatric EHPVO are limited\u003c/p\u003e\u003ch2\u003eObjectives\u003c/h2\u003e \u003cp\u003eTo compare the effectiveness of contrast-enhanced computed tomography (CT) and percutaneous portal venography (PVG) in visualizing intrahepatic portal vein segments and various findings such as varices, shunts, and portal biliopathy in children with non-cirrhotic, non-malignant, chronic extrahepatic portal vein obstruction (EHPVO).\u003c/p\u003e\u003ch2\u003eMaterials \u0026amp; Methods\u003c/h2\u003e \u003cp\u003eThis retrospective single-center study included pediatric patients with EHPVO between 2018 and 2024. All patients underwent contrast-enhanced CT and PVG before attempted portal vein recanalization. Imaging findings were compared for intrahepatic portal vein visualization, cavernoma type, presence of varices and shunts, and portal biliopathy. Statistical analysis included McNemar's test, chi-square/Fisher\u0026rsquo;s exact test, and one-way ANOVA.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThis study included 18 pediatric patients (mean age, 7.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8 years; 12 males). PVG demonstrated significantly higher visualization rates of intrahepatic portal vein branches in segments 4\u0026ndash;8 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.013\u0026ndash;0.035) compared to CT. CT failed to identify some branches that were patent on PVG. Cavernoma type showed no significant association with patient age or presence of portal biliopathy (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Gallbladder and gastric varices were strongly associated and inversely related to splenorenal shunts (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.029).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eCT and PVG are complementary tools in the management of pediatric EHPVO. While CT supports pre-procedural planning, PVG provides superior intrahepatic vascular detail and facilitates recanalization. However, the lack of predictive criteria for procedural success highlights the need for further research in patient selection.\u003c/p\u003e","manuscriptTitle":"Percutaneous Portal Venography vs. Contrast-Enhanced CT in Pediatric Extrahepatic Portal Vein Obstruction: A Comparative Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-30 16:13:21","doi":"10.21203/rs.3.rs-6701430/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b6a09cfe-49ef-4952-81f0-d7565ae0c47b","owner":[],"postedDate":"May 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-07-28T19:53:23+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-30 16:13:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6701430","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6701430","identity":"rs-6701430","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}