A multi-observer study on the effectiveness of Dual-energy CT in diagnosing sacral fractures: assessment of diagnostic accuracy and intra- and inter-rater reliabilities

A multi-observer study on the effectiveness of Dual-energy CT in diagnosing sacral fractures: assessment of diagnostic accuracy and intra- and inter-rater reliabilities | 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 A multi-observer study on the effectiveness of Dual-energy CT in diagnosing sacral fractures: assessment of diagnostic accuracy and intra- and inter-rater reliabilities Takahiro Oda, Shimpei Kitada, Hitoshi Hirase, Kenjiro Iwasa, Takahiro Niikura This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4859889/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 24 Jan, 2025 Read the published version in European Journal of Trauma and Emergency Surgery → Version 1 posted 7 You are reading this latest preprint version Abstract Purpose Evaluating sacral fractures is crucial in fragility fractures of the pelvis. Dual-energy CT (DECT) is considered useful for diagnosing unclear fractures on single-energy CT (SECT). This study aims to investigate the effectiveness of DECT in diagnosing sacral fractures. Methods Thirty cases suspected of sacral fractures who underwent SECT, DECT, and MRI, and were diagnosed for the presence of fractures by three inexperienced surgeons (group I) and three experienced surgeons (group E). Diagnoses were made initially using SECT (pre-DECT) and then reassessed including DECT (post-DECT). This process was repeated twice. Presence of fractures was determined based on MRI. Sensitivity, specificity, inter-rater and intra-rater reliability, and diagnostic accuracy were calculated. Diagnostic accuracy was statistically compared between two groups. Results Sensitivity was 0.73 in pre-DECT and 0.9 in post-DECT, while specificity was 0.83 in pre-DECT and 0.91 in post-DECT. Sensitivity significantly improved with the addition of DECT (McNemar test: p < 0.001). Intra-rater reliability (Fleiss' kappa coefficient) was 0.44 in pre-DECT and 0.76 in post-DECT. Inter-rater reliability (Cohen's kappa coefficient) was 0.6 in pre-DECT and 0.81 in post-DECT. Diagnostic accuracy was significantly lower in group I than group E in pre-DECT (P = 0.019, 0.048), but there was no significant difference between two groups in post-DECT. Conclusion Combined use of DECT with SECT improved the detection rate of sacral fractures and enhanced intra-rater and inter-rater reliability. High diagnostic accuracy was achieved regardless of the observer's experience. These results indicate that DECT is a useful imaging modality for diagnosing sacral fractures. Sacral fracture Dual- energy CT Inter-rater reliability Intra-rater reliability Fragility fractures of the pelvis Figures Figure 1 Figure 2 Figure 3 Introduction Fragility fractures of the pelvis (FFP) are fractures that occur due to low-energy trauma based on bone fragility [ 1 – 3 ]. The number of patients with FFP is rapidly increasing with the advent of the super-aging society [ 4 , 5 ]. Due to the nature of being a fracture that predominantly occurs in the elderly, the high mortality rate due to complications, as well as the decline in activities of daily living (ADL) after injury, are concerning [6.7]. Therefore, it is crucial to ensure a reliable diagnosis and provide prompt and appropriate treatment. Accurate identification of the fracture type is very important in the treatment of FFP. The FFP classification, proposed by Rommens and Hoffmann in 2013, is most commonly used for evaluating the fracture type of FFP [ 8 ]. This classification is based on CT imaging and categorizes fractures into types I to IV according to the level of instability. There are many centers that use this as a crucial factor when selecting treatment strategies [ 9 – 10 ]. Assessing damage to the posterior elements of the pelvic ring is very important for accurately diagnosing the type of fracture, but it may be difficult to diagnose with X-ray photograph or single energy CT (SECT) image alone [ 11 ]. In particular, cases of sacral fractures without displacement are at risk of being overlooked during initial examination. In such cases, it cannot be ruled out that improper loading may lead to the progression of displacement later on, resulting in more challenging treatment. As the likelihood of requiring surgical treatment ascends with the progression to more complex fracture types in FFP [ 12 – 13 ], it is crucial to avoid overlooking sacral fractures as much as possible during the initial presentation. It has been reported that MRI has a higher diagnostic rate compared to SECT [ 14 ], but due to patient background and cost considerations, it is difficult to immediately perform MRI on all patients. Therefore, a simple imaging test with a high diagnostic rate that can serve as a substitute for MRI would be very useful. Dual energy CT (DECT) is a method of CT imaging that uses two different energy levels of X-rays, allowing for the acquisition of more information compared to conventional SECT [ 15 ]. This imaging test performs analysis using data obtained from imaging at two different tube voltages. We can obtain clinically useful additional information compared to conventional SECT, which is imaged at a single tube voltage. By rapidly switching between two tube voltages, 80 kVp and 140 kVp, within 0.25 milliseconds, DECT can be performed with the equivalent radiation dose and imaging time to that of SECT. It can be performed simultaneously with SECT, which would be routinely taken at the time of diagnosis of FFP. It is capable of imaging regardless of the presence of metal in the body, and it is also a feature that does not limit the selection of cases. DECT is excellent at detecting bone marrow edema and incomplete fractures and is considered a useful alternative to MRI for diagnosing acute vertebral compression fractures [ 16 ]. We have utilized these features to diagnose sacral fractures using DECT (Fig. 1 ). There have been reports indicating that DECT shows similar diagnostic accuracy to MRI in detecting sacral fractures [ 17 ]. However, there have been no studies investigating the intraclass correlation coefficients (ICC) when assessing DECT images by multiple observers. The aim of this study is to investigate whether DECT is an effective imaging modality for diagnosing sacral fractures by assessing DECT images of cases suspected of sacral fractures by multiple observers and examining the diagnostic accuracy, inter-rater reliability, and intra-rater reliability. Materials and Methods Patient Population Since October 2018 to March 2023, thirty patients (3 male and 27 female) with suspected sacral fractures who underwent SECT, DECT and MRI at our hospital were included in the study. The mean age was 81.2 (range, 32–96) years. Calculation of Sample Size With reference to similar previous studies [ 18 ], an inter-rater reliability of 0.7 was assumed. The number of observers was set at five and the sample size was calculated for Fleiss’s Kappa [ 19 ], a minimum of 30 cases were needed. Therefore, based on this result, we decided to have 6 observers and 30 cases. Study design Images (SECT and DECT) of 30 cases were anonymized. Six orthopedic surgeons assessed for sacral fractures. Three out of six had less than four years (inexperienced group: group I), while the other three had over 10 years of medical experience (experienced group: group E). No information regarding patient background or clinical symptoms was provided, and the assessment was based solely on the image data. Each observer initially assessed sacral fractures using SECT images alone (pre-DECT). Subsequently, after adding DECT images as new information, the observers reassessed for the sacral fractures (post-DECT). Observers were not allowed to change their answers after making and submitting their initial assessments based on their first impressions. The same procedure was repeated twice with an interval of over three months between each session (Fig. 2 ). The final determination of the presence or absence of fractures was made based on the MRI interpretation by the radiologist as the “gold standard” observer. Data collection and analysis The results were aggregated and statistically analyzed by one investigator (study leader) separate from the 6 observers. From the aggregated diagnostic results, we calculated the sensitivity and specificity for detecting sacral fractures, inter-rater reliability (Fleiss' kappa coefficient), and intra-rater reliability (Cohen's kappa coefficient) for both pre-DECT and post-DECT assessments. To investigate the impact of years of experience as a surgeon, values for the aforementioned values related to the diagnostic accuracy were calculated for the overall group (group O), the group I, and the group E. For statistical comparisons of diagnostic ability between used SECT alone and used a combination of SECT and DECT, we compared the sensitivity and specificity using a paired proportion test (the McNemar test). Next, the 30 cases were divided into three patterns based on the type of fracture (unilateral fracture pattern: U type [11 cases], bilateral fracture pattern: B type [9 cases], no fracture pattern: N type [10 cases]) (Fig. 3 ). We calculated the diagnostic accuracy rates for each type, with "gold standard" as the correct answer. Furthermore, statistical comparisons were conducted between the group I and group E for diagnostic accuracy rates in both pre-DECT and post-DECT. Statistical analyses were performed using Fisher’s exact test. Statistical analysis Statistical analyses of sensitivity and specificity, intra-rater and inter-rater reliabilities were carried out using software (EZR version 1.61, Saitama Medical Center, Jichi Medical University, Saitama, Japan), which is a graphical user interface for R (The R Foundation for Statistical Computing, Vienna, Austria) [ 20 ]. Inter-rater and intra-rater reliability were graded according to the description by Landis and Koch [ 21 ]. That is, 1 was considered perfect, 0.81 and above as almost perfect, 0.80 to 0.61 as substantial, 0.60 to 0.41 as moderate, 0.40 to 0.21 as fair and less than 0.20 as poor. McNemar test and Fisher’s exact were carried out using BellCurve for Excel V.3.0 (Social Survey Research Information, Tokyo, Japan). Statistical significance was set at p < 0.05. The dual‑energy CT method Dual-energy CT (DECT) was performed using a 256-slice CT scanner (Revolution Apex; GE HealthCare, Milwaukee, WI, USA). No contrast agent was used in all cases. The acquisition parameters were applied as follows: fast kV switching dual-energy scan with 80 and 140 kVp; setting noise index 12 with automatic tube current modulation; collimation thickness, 0.625 mm; helical scan type; rotation time, 0.5 s; helical pitch, 0.992; deep learning reconstruction at medium levels; and standard reconstruction type. In image post-processing, dual-energy material density analysis of water and calcium was conducted. Results Sensitivity and specificity for detecting sacral fractures The sensitivity (with 95% confidence interval [CI]) for detecting sacral fractures in pre-DECT was 0.73 (0.68 to 0.79) in the group O, 0.68 (0.6 to 0.77) in the group I, and 0.78 (0.7 to 0.85) in the group E. In post-DECT, the sensitivity was 0.9 (0.86 to 0.94) in the group O, 0.9 (0.85 to 0.95) in the group I, and 0.9 (0.85 to 0.96) in the group E. On the other hand, the specificity(with 95% CI) for sacral fracture detection was 0.83 (0.76 to 0.9) in the group O, 0.77 (0.66 to 0.87) in the group I, and 0.9 (0.82 to 0.98) in the group E in pre-DECT. In post-DECT, the specificity was 0.91 (0.86 to 0.96) in the group O, 0.88 (0.80 to 0.96) in the group I, and 0.93 (0.87 to 1) in the group E (Table 1 ). In all groups, both sensitivity and specificity were higher in post-DECT compared to pre-DECT. The McNemar test result indicated a significant enhancement in sensitivity when DECT was used in combination compared to SECT alone (p < 0.001). Inter-Rater Reliability In pre-DECT, Fleiss' kappa coefficient (with 95% CI) reflecting inter-rater reliability was 0.442 (0.245 to 0.83) in the group O, 0.51 (0.215 to 0.799) in the group I and 0.439 (0.346 to 0.93) in the group E. In pre-DECT, the reliability was moderate in all groups. In post-DECT, the coefficient was 0.761 (0.462 to 1) in the group O, 0.735 (0. 47 to 1) in the group I and 0.743 (0.381 to 0.964) in the group E. In post-DECT, the reliability was substantial in all groups. Inter-rater reliability increased markedly in all groups when DECT was used in combination (Table 2 ). Intra-Rater Reliability In pre-DECT, Cohen' kappa coefficient (with 95% CI) reflecting intra-rater reliability was 0.598 (0.482 to 0.714) in the group O, 0.564 (0.404 to 0.725) in the group I and 0.64 (0.481 to 0.8) in the group E. In pre-DECT, the reliability was moderate in the group O and in the group I, and substantial in the group E. In post-DECT, the coefficient was 0.81 (0.721 to 0.899) in the group O, 0.783 (0. 649 to 0.917) in the group I and 0.836 (0.719 to 0.952) in the group E. In post-DECT, the reliability was almost perfect in the group O and in the group E, and substantial in the group I. Intra-rater reliability increased in all groups when DECT was used in combination (Table 3 ). Diagnostic accuracy rate of sacral fracture The diagnostic accuracy rates in pre-DECT were as follows: in the group O, 80.3% for the H type, 64.3% for the B type, and 83.3% for the N type; in the group I, 77.2% for the H type, 57.4% for the B type, and 76.6% for the N type; and in the group E, 83.3% for the H type, 72.2% for the B type, and 90% for the N type. On the other hand, the rates in post-DECT were as follows: in the group O, 94.6% for the H type, 85.2% for the B type, and 90.8% for the N type; in the group I, 98.5% for the H type, 81.5% for the B type, and 88.3% for the N type; and in the group E, 90.9% for the H type, 88.9% for the B type, and 93.3% for the N type. In all groups, regardless of the type of fracture, the diagnostic accuracy was higher when combined with DECT. The results were slightly lower in B type, which comparison with the unaffected side was impossible (Table 4 ). Statistical analysis revealed that the diagnostic accuracy rate in the group I was significantly lower compared to the group E in both the 1st and 2nd cycles in pre-DECT (1st cycle: p = 0.019, 2nd cycle: p = 0.048). However, there was no statistically significant difference about the diagnostic accuracy rate between the two groups in both two cycles in post-DECT (1st cycle: p = 1, 2nd cycle: p = 0.813) (Table 5 ). Discussion To the best of our knowledge, this paper is the first to examine the inter-rater and intra-rater agreement rates of DECT in the diagnosis of FFP. This study revealed that the detection sensitivity and specificity of sacral fractures increased when diagnosed with DECT in addition to SECT compared to SECT alone. Furthermore, there was also an increase in inter-rater reliability, intra-rater reliability, and diagnostic accuracy. These findings were similarly observed even in the group with less years of medical experience, demonstrating that DECT can be a valuable tool in the diagnosis of sacral fractures. With the advent of an aging society, the number of patients with FFP is increasing rapidly worldwide. These fractures often occur as a result of low-energy trauma such as falls against a background of osteoporosis. Hence, they are fractures that anyone involved in medical treatment may encounter in the future, regardless of the scale of the hospital. Initially, when the concept of FFP was proposed, surgical treatment was considered preferable in all cases in fracture types with high instability (Rommens’ FFP classification type III and IV) [ 8 ]. In recent years, there have been more reports of conservative treatment being chosen as the primary option, regardless of the fracture type of FFP [ 22 , 23 ]. Accurate and reliable assessment of fracture type is essential for successful conservative treatment in FFP. If posterior element injuries are overlooked, the fracture type may be underestimated. Inappropriate treatment of such cases could lead to progression of the fracture type. This tendency for fracture types to progress easily is a characteristic of FFP and is one of the reasons why treatment is challenging [ 24 ]. There are some reports indicate that Type III and IV cases will be more likely to require surgery ultimately than Type I and II cases [ 25 , 26 ], and preventing progression of fracture type is clearly linked to the prognosis of FFP treatment. Among the components of the posterior elements of the pelvic ring, sacral fractures are particularly difficult to diagnoses. It is known that the sacral fractures are often overlooked when diagnosed only by X ray photographs [ 27 ], and that the diagnostic rate is not 100% even when evaluated with SECT [ 11 ]. Therefore, accurate diagnosis of sacral fractures is crucial in the treatment of FFP, and we consider imaging modalities that enable this diagnosis are highly valuable. SECT is a useful imaging modality that can captures large areas quickly and reveals the three-dimensional structure of organs. It provides much more information compared to plain X-ray photograph. In cases of FFP, SECT is generally performed in all cases [ 6 , 8 , 23 ]. In this study, when diagnosis of sacral fracture was made using only SECT, the accuracy rate was only 70-71.1% in the inexperienced group and 84.4–85.6% in the experienced group. Similar to other reports, the diagnostic rate for sacral fractures using only SECT was far from 100%. Furthermore, this study also revealed that the accuracy rate varied significantly with the surgeon's years of experience. Inter-rater and intra-rater reliability were not very high, suggesting that X-ray photograph and SECT alone may be inadequate to determine an accurate diagnosis of FFP depending on the case. To obtain more detailed information, it is necessary to use contrast medium or increase the X-ray dose. However, there are concerns about physical invasion and increased radiation exposure to the patient in such cases. Although SECT can be performed quickly and has better diagnostic capabilities than X-ray photograph, we believe that imaging modalities with greater diagnostic accuracy are desirable for reliably diagnosing the fracture type of FFP. There's no doubt that MRI is extremely useful imaging modality in diagnosing fractures. Specifically, it is the most effective in diagnosing fresh vertebral compression fractures [ 28 ]. Additionally, MRI is highly useful in identifying incomplete fractures with intact cortical bone continuity, and it is known to have a higher detection rate for sacral fractures compared to SECT [ 11 , 14 ]. MRI, which can detect sacral fractures with high accuracy, is very useful when diagnosing FFP. However, it is difficult to perform MRI in all cases where fractures are suspected due to several factors. The first factor is the patient's background. If a patient has metal in their body following cardiology or neurosurgical treatment, or if the patient cannot tolerate the examination itself due to claustrophobia or dementia, diagnosis must be conducted without using MRI. The second factor is the issue of medical costs. Due to certain costs, it is not practical to perform MRI in every suspected fracture case. Although MRI is effective tool for diagnosing sacral fractures, it cannot be performed urgently in every suspected case. Therefore, an alternative imaging modality to MRI would be beneficial. DECT is an imaging modality that can be rapidly performed concurrently with SECT without increasing radiation exposure, and it is utilized in various fields. In the field of orthopedic surgery, images processed to suppress calcium and emphasize water are primarily used. In this setting, edema within the bone marrow is depicted distinctly as high-water density area, which is considered useful for diagnosing conditions such as fresh vertebral compression fractures and incomplete fractures with maintained cortical bone continuity [ 16 , 29 ]. This study revealed that using DECT improves the accuracy of diagnosing sacral fractures. Notably, even for the inexperienced group, who are relatively unfamiliar with interpreting CT images, the addition of DECT greatly increased diagnostic accuracy, making it comparable to that of the experienced group. These results suggest that DECT clearly visualizes sacral fractures to the extent that anyone can diagnose them. Additionally, improved intra- and inter-rater reliability suggests that DECT is a highly reproducible examination in the diagnosis of sacral fractures. A major advantage of DECT is that accurate classification of FFP enables rapid determination of treatment strategies. Furthermore, we believe that DECT is also good usability imaging modality because it can be used for cases that are difficult to perform MRI and is not different from SECT in terms of cost. In this study, diagnoses were based solely on imaging. However, in actual clinical practice, detailed medical history and physical examinations are conducted before imaging, which should bring diagnostic accuracy closer to 100%. The results of this study suggest that using DECT to diagnose sacral fractures is a very effective method. Ultimately, we are considering performing DECT simultaneously with SECT in all cases of suspected fracture in our institution. DECT is a rapid and useful imaging modality with a high rate of detecting fractures. However, there is a limitation that prevents imaging on CT devices that do not support DECT imaging. As it is impossible to retrofit this capability later, it is desirable for CT equipment capable of DECT imaging to become more widespread in many facilities in the future. It is crucial to inform the doctors responsible for the initial treatment beforehand to perform CT scan under DECT imaging conditions from the outset if a fracture is suspected. This is because once a scan is performed under SECT imaging conditions, it cannot be reconstructed into DECT images later. Conclusion Combining DECT with SECT improved the detection capability and intra- and inter-rater reliability for sacral fractures. Furthermore, the high diagnostic accuracy achieved regardless of the observers' years of experience suggests that DECT could be a highly useful imaging modality as an alternative to MRI for diagnosing sacral fractures. Declarations Data availability The original dataset generated during the current study is available from the corresponding author on reasonable request. 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Supplementary Files Tables.docx Cite Share Download PDF Status: Published Journal Publication published 24 Jan, 2025 Read the published version in European Journal of Trauma and Emergency Surgery → Version 1 posted Editorial decision: Revision requested 04 Oct, 2024 Reviews received at journal 28 Aug, 2024 Reviewers agreed at journal 15 Aug, 2024 Reviewers invited by journal 12 Aug, 2024 Editor assigned by journal 12 Aug, 2024 Submission checks completed at journal 07 Aug, 2024 First submitted to journal 05 Aug, 2024 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. 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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-4859889","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":346433156,"identity":"678f97ff-e26a-46ce-9489-266aa8b97116","order_by":0,"name":"Takahiro Oda","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+UlEQVRIiWNgGAWjYFACNhDBDESMDQc+VIDYzA14NfDAtbA3Nx6ccYYBrJdILTzHmw9ztoE4BLTYsx9L/MBQYS3PIJHYcJhxXm00fztQy4+Kbbht4Uk7LMFwJt2wAaSlcNvx3BmHGRsYe87cxuOw9AYJxjagMpCWmduO5QLtamBmbMOjhf958w+gFnuwFt45x3LnE9QikXYMZEtiA89BoJaGmtwNBLXceJZmkXAmPbmNvbHh4IxjB3I3ArUcxOcX9v404xsfKqxt+5nZH3/4UFOXO+/84YMPflTg1gIGCQzQRMDAcBhMHsCvHhXUkaJ4FIyCUTAKRggAAOjCXqlHAu/fAAAAAElFTkSuQmCC","orcid":"","institution":"Department of Orthopaedic Surgery, Hyogo Prefectural Nishinomiya Hospital","correspondingAuthor":true,"prefix":"","firstName":"Takahiro","middleName":"","lastName":"Oda","suffix":""},{"id":346433157,"identity":"dda3fa55-b0e4-44df-85ce-d331755c28e1","order_by":1,"name":"Shimpei Kitada","email":"","orcid":"","institution":"Department of Orthopaedic Surgery, Hyogo Prefectural Nishinomiya Hospital","correspondingAuthor":false,"prefix":"","firstName":"Shimpei","middleName":"","lastName":"Kitada","suffix":""},{"id":346433159,"identity":"7f2ba512-f7d7-4e7d-b6d7-62cee5cbfcfc","order_by":2,"name":"Hitoshi Hirase","email":"","orcid":"","institution":"Trauma Reconstruction Center, Hyogo Prefectural Nishinomiya Hospital","correspondingAuthor":false,"prefix":"","firstName":"Hitoshi","middleName":"","lastName":"Hirase","suffix":""},{"id":346433160,"identity":"200171a3-6cd2-4ea1-92da-cdb8efa7d1e1","order_by":3,"name":"Kenjiro Iwasa","email":"","orcid":"","institution":"Department of Orthopaedic Surgery, Hyogo Prefectural Nishinomiya Hospital","correspondingAuthor":false,"prefix":"","firstName":"Kenjiro","middleName":"","lastName":"Iwasa","suffix":""},{"id":346433162,"identity":"5c1d3e8a-8f99-4f14-bd2a-b822bf2a904f","order_by":4,"name":"Takahiro Niikura","email":"","orcid":"","institution":"Department of Orthopaedic Surgery, Hyogo Prefectural Nishinomiya Hospital","correspondingAuthor":false,"prefix":"","firstName":"Takahiro","middleName":"","lastName":"Niikura","suffix":""}],"badges":[],"createdAt":"2024-08-05 07:07:05","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4859889/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4859889/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00068-024-02673-x","type":"published","date":"2025-01-24T15:57:13+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":64389464,"identity":"51058d2b-c7bf-4ccd-b62e-630e75ad9245","added_by":"auto","created_at":"2024-09-12 13:01:50","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":816221,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRepresentative images of sacral fracture.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSingle energy computed tomography (SECT) images (a, b) , dual energy CT images (DECT) (c, d), and MRI images (e, f) of sacral fracture. SECT images: a, coronal and b, axial. DECT images: c, coronal and d, axial. MRI images: e, coronal and f, axial. SECT does not definitively suggest signs indicative of fracture. DECT shows green areas of high-water density distal to the left sacrum (red circle). MRI shows brightness changes indicative of edema in the same area as the DECT lesion (red circle). In this case, we diagnosed a left sacral fracture. In this way, DECT can clearly delineate sacral fractures that cannot be identified by SECT.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-4859889/v1/1b2203bbaa6e1d8b25f7771e.png"},{"id":64389463,"identity":"9ac22a88-7b12-4abe-a9b7-9817a7ba991f","added_by":"auto","created_at":"2024-09-12 13:01:50","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":31565,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStudy design\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSix orthopedic surgeons assessed the presence of sacral fractures in 30 anonymized images (SECT and DECT). Three of them had over 10 years of medical experience (Experienced Group: Group E), while the remaining three had less than 4 years of experience (Inexperienced Group: Group I). Without any additional information, observers initially assessed the presence of sacral fractures using SECT images alone (pre-DECT). Subsequently, they assessed the presence of sacral fractures after adding DECT images (post-DECT). The data were aggregated by a study leader separate from the six observers. This procedure was repeated twice, with an interval of over three months.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-4859889/v1/e9c83d5f344d22926f76dc91.png"},{"id":64389465,"identity":"db5dd5b4-0e5a-4aa9-8478-d1360f4021b5","added_by":"auto","created_at":"2024-09-12 13:01:50","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":192376,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePatterns of sacral fracture\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe divided the fractures into three patterns: U type, B type, and N type, based on the fracture type. U type means unilateral fracture, B type means bilateral fracture and N type means no fracture. The red lines indicate fracture lines.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-4859889/v1/42eedf5d0e57b6ff76bdf3e0.png"},{"id":74858338,"identity":"9602ce57-ee5e-44fc-9181-7fc553776419","added_by":"auto","created_at":"2025-01-27 16:08:12","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1774087,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4859889/v1/f92a8a2d-f0a3-4572-a63a-a5dd992e05a0.pdf"},{"id":64389462,"identity":"2d115246-9cd2-41db-a428-aaa269c4dc6c","added_by":"auto","created_at":"2024-09-12 13:01:50","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":188887,"visible":true,"origin":"","legend":"","description":"","filename":"Tables.docx","url":"https://assets-eu.researchsquare.com/files/rs-4859889/v1/17b50d12ae635074cf0fb571.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"A multi-observer study on the effectiveness of Dual-energy CT in diagnosing sacral fractures: assessment of diagnostic accuracy and intra- and inter-rater reliabilities","fulltext":[{"header":"Introduction","content":"\u003cp\u003eFragility fractures of the pelvis (FFP) are fractures that occur due to low-energy trauma based on bone fragility [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The number of patients with FFP is rapidly increasing with the advent of the super-aging society [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Due to the nature of being a fracture that predominantly occurs in the elderly, the high mortality rate due to complications, as well as the decline in activities of daily living (ADL) after injury, are concerning [6.7]. Therefore, it is crucial to ensure a reliable diagnosis and provide prompt and appropriate treatment.\u003c/p\u003e \u003cp\u003eAccurate identification of the fracture type is very important in the treatment of FFP. The FFP classification, proposed by Rommens and Hoffmann in 2013, is most commonly used for evaluating the fracture type of FFP [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. This classification is based on CT imaging and categorizes fractures into types I to IV according to the level of instability. There are many centers that use this as a crucial factor when selecting treatment strategies [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Assessing damage to the posterior elements of the pelvic ring is very important for accurately diagnosing the type of fracture, but it may be difficult to diagnose with X-ray photograph or single energy CT (SECT) image alone [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In particular, cases of sacral fractures without displacement are at risk of being overlooked during initial examination. In such cases, it cannot be ruled out that improper loading may lead to the progression of displacement later on, resulting in more challenging treatment. As the likelihood of requiring surgical treatment ascends with the progression to more complex fracture types in FFP [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], it is crucial to avoid overlooking sacral fractures as much as possible during the initial presentation. It has been reported that MRI has a higher diagnostic rate compared to SECT [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], but due to patient background and cost considerations, it is difficult to immediately perform MRI on all patients. Therefore, a simple imaging test with a high diagnostic rate that can serve as a substitute for MRI would be very useful.\u003c/p\u003e \u003cp\u003eDual energy CT (DECT) is a method of CT imaging that uses two different energy levels of X-rays, allowing for the acquisition of more information compared to conventional SECT [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. This imaging test performs analysis using data obtained from imaging at two different tube voltages. We can obtain clinically useful additional information compared to conventional SECT, which is imaged at a single tube voltage. By rapidly switching between two tube voltages, 80 kVp and 140 kVp, within 0.25 milliseconds, DECT can be performed with the equivalent radiation dose and imaging time to that of SECT. It can be performed simultaneously with SECT, which would be routinely taken at the time of diagnosis of FFP. It is capable of imaging regardless of the presence of metal in the body, and it is also a feature that does not limit the selection of cases. DECT is excellent at detecting bone marrow edema and incomplete fractures and is considered a useful alternative to MRI for diagnosing acute vertebral compression fractures [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. We have utilized these features to diagnose sacral fractures using DECT (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). There have been reports indicating that DECT shows similar diagnostic accuracy to MRI in detecting sacral fractures [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. However, there have been no studies investigating the intraclass correlation coefficients (ICC) when assessing DECT images by multiple observers.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe aim of this study is to investigate whether DECT is an effective imaging modality for diagnosing sacral fractures by assessing DECT images of cases suspected of sacral fractures by multiple observers and examining the diagnostic accuracy, inter-rater reliability, and intra-rater reliability.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatient Population\u003c/h2\u003e \u003cp\u003eSince October 2018 to March 2023, thirty patients (3 male and 27 female) with suspected sacral fractures who underwent SECT, DECT and MRI at our hospital were included in the study. The mean age was 81.2 (range, 32\u0026ndash;96) years.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eCalculation of Sample Size\u003c/h2\u003e \u003cp\u003eWith reference to similar previous studies [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], an inter-rater reliability of 0.7 was assumed. The number of observers was set at five and the sample size was calculated for Fleiss\u0026rsquo;s Kappa [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], a minimum of 30 cases were needed. Therefore, based on this result, we decided to have 6 observers and 30 cases.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStudy design\u003c/h2\u003e \u003cp\u003eImages (SECT and DECT) of 30 cases were anonymized. Six orthopedic surgeons assessed for sacral fractures. Three out of six had less than four years (inexperienced group: group I), while the other three had over 10 years of medical experience (experienced group: group E). No information regarding patient background or clinical symptoms was provided, and the assessment was based solely on the image data. Each observer initially assessed sacral fractures using SECT images alone (pre-DECT). Subsequently, after adding DECT images as new information, the observers reassessed for the sacral fractures (post-DECT). Observers were not allowed to change their answers after making and submitting their initial assessments based on their first impressions. The same procedure was repeated twice with an interval of over three months between each session (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The final determination of the presence or absence of fractures was made based on the MRI interpretation by the radiologist as the \u0026ldquo;gold standard\u0026rdquo; observer.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eData collection and analysis\u003c/h2\u003e \u003cp\u003eThe results were aggregated and statistically analyzed by one investigator (study leader) separate from the 6 observers. From the aggregated diagnostic results, we calculated the sensitivity and specificity for detecting sacral fractures, inter-rater reliability (Fleiss' kappa coefficient), and intra-rater reliability (Cohen's kappa coefficient) for both pre-DECT and post-DECT assessments. To investigate the impact of years of experience as a surgeon, values for the aforementioned values related to the diagnostic accuracy were calculated for the overall group (group O), the group I, and the group E. For statistical comparisons of diagnostic ability between used SECT alone and used a combination of SECT and DECT, we compared the sensitivity and specificity using a paired proportion test (the McNemar test). Next, the 30 cases were divided into three patterns based on the type of fracture (unilateral fracture pattern: U type [11 cases], bilateral fracture pattern: B type [9 cases], no fracture pattern: N type [10 cases]) (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). We calculated the diagnostic accuracy rates for each type, with \"gold standard\" as the correct answer. Furthermore, statistical comparisons were conducted between the group I and group E for diagnostic accuracy rates in both pre-DECT and post-DECT. Statistical analyses were performed using Fisher\u0026rsquo;s exact test.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analyses of sensitivity and specificity, intra-rater and inter-rater reliabilities were carried out using software (EZR version 1.61, Saitama Medical Center, Jichi Medical University, Saitama, Japan), which is a graphical user interface for R (The R Foundation for Statistical Computing, Vienna, Austria) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Inter-rater and intra-rater reliability were graded according to the description by Landis and Koch [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. That is, 1 was considered perfect, 0.81 and above as almost perfect, 0.80 to 0.61 as substantial, 0.60 to 0.41 as moderate, 0.40 to 0.21 as fair and less than 0.20 as poor. McNemar test and Fisher\u0026rsquo;s exact were carried out using BellCurve for Excel V.3.0 (Social Survey Research Information, Tokyo, Japan). Statistical significance was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eThe dual‑energy CT method\u003c/h2\u003e \u003cp\u003eDual-energy CT (DECT) was performed using a 256-slice CT scanner (Revolution Apex; GE HealthCare, Milwaukee, WI, USA). No contrast agent was used in all cases. The acquisition parameters were applied as follows: fast kV switching dual-energy scan with 80 and 140 kVp; setting noise index 12 with automatic tube current modulation; collimation thickness, 0.625 mm; helical scan type; rotation time, 0.5 s; helical pitch, 0.992; deep learning reconstruction at medium levels; and standard reconstruction type. In image post-processing, dual-energy material density analysis of water and calcium was conducted.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec10\"\u003e\n \u003ch2\u003eSensitivity and specificity for detecting sacral fractures\u003c/h2\u003e\n \u003cp\u003eThe sensitivity (with 95% confidence interval [CI]) for detecting sacral fractures in pre-DECT was 0.73 (0.68 to 0.79) in the group O, 0.68 (0.6 to 0.77) in the group I, and 0.78 (0.7 to 0.85) in the group E. In post-DECT, the sensitivity was 0.9 (0.86 to 0.94) in the group O, 0.9 (0.85 to 0.95) in the group I, and 0.9 (0.85 to 0.96) in the group E. On the other hand, the specificity(with 95% CI) for sacral fracture detection was 0.83 (0.76 to 0.9) in the group O, 0.77 (0.66 to 0.87) in the group I, and 0.9 (0.82 to 0.98) in the group E in pre-DECT. In post-DECT, the specificity was 0.91 (0.86 to 0.96) in the group O, 0.88 (0.80 to 0.96) in the group I, and 0.93 (0.87 to 1) in the group E (Table \u003cspan\u003e1\u003c/span\u003e). In all groups, both sensitivity and specificity were higher in post-DECT compared to pre-DECT. The McNemar test result indicated a significant enhancement in sensitivity when DECT was used in combination compared to SECT alone (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\u003c/table\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec11\"\u003e\n \u003ch2\u003eInter-Rater Reliability\u003c/h2\u003e\n \u003cp\u003eIn pre-DECT, Fleiss\u0026apos; kappa coefficient (with 95% CI) reflecting inter-rater reliability was 0.442 (0.245 to 0.83) in the group O, 0.51 (0.215 to 0.799) in the group I and 0.439 (0.346 to 0.93) in the group E. In pre-DECT, the reliability was moderate in all groups. In post-DECT, the coefficient was 0.761 (0.462 to 1) in the group O, 0.735 (0. 47 to 1) in the group I and 0.743 (0.381 to 0.964) in the group E. In post-DECT, the reliability was substantial in all groups. Inter-rater reliability increased markedly in all groups when DECT was used in combination (Table \u003cspan\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\"\u003e\n \u003ch2\u003eIntra-Rater Reliability\u003c/h2\u003e\n \u003cp\u003eIn pre-DECT, Cohen\u0026apos; kappa coefficient (with 95% CI) reflecting intra-rater reliability was 0.598 (0.482 to 0.714) in the group O, 0.564 (0.404 to 0.725) in the group I and 0.64 (0.481 to 0.8) in the group E. In pre-DECT, the reliability was moderate in the group O and in the group I, and substantial in the group E. In post-DECT, the coefficient was 0.81 (0.721 to 0.899) in the group O, 0.783 (0. 649 to 0.917) in the group I and 0.836 (0.719 to 0.952) in the group E. In post-DECT, the reliability was almost perfect in the group O and in the group E, and substantial in the group I. Intra-rater reliability increased in all groups when DECT was used in combination (Table \u003cspan\u003e3\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\u003c/table\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\"\u003e\n \u003ch2\u003eDiagnostic accuracy rate of sacral fracture\u003c/h2\u003e\n \u003cp\u003eThe diagnostic accuracy rates in pre-DECT were as follows: in the group O, 80.3% for the H type, 64.3% for the B type, and 83.3% for the N type; in the group I, 77.2% for the H type, 57.4% for the B type, and 76.6% for the N type; and in the group E, 83.3% for the H type, 72.2% for the B type, and 90% for the N type. On the other hand, the rates in post-DECT were as follows: in the group O, 94.6% for the H type, 85.2% for the B type, and 90.8% for the N type; in the group I, 98.5% for the H type, 81.5% for the B type, and 88.3% for the N type; and in the group E, 90.9% for the H type, 88.9% for the B type, and 93.3% for the N type. In all groups, regardless of the type of fracture, the diagnostic accuracy was higher when combined with DECT. The results were slightly lower in B type, which comparison with the unaffected side was impossible (Table \u003cspan\u003e4\u003c/span\u003e). Statistical analysis revealed that the diagnostic accuracy rate in the group I was significantly lower compared to the group E in both the 1st and 2nd cycles in pre-DECT (1st cycle: p\u0026thinsp;=\u0026thinsp;0.019, 2nd cycle: p\u0026thinsp;=\u0026thinsp;0.048). However, there was no statistically significant difference about the diagnostic accuracy rate between the two groups in both two cycles in post-DECT (1st cycle: p\u0026thinsp;=\u0026thinsp;1, 2nd cycle: p\u0026thinsp;=\u0026thinsp;0.813) (Table \u003cspan\u003e5\u003c/span\u003e).\u003c/p\u003e\n \n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eTo the best of our knowledge, this paper is the first to examine the inter-rater and intra-rater agreement rates of DECT in the diagnosis of FFP. This study revealed that the detection sensitivity and specificity of sacral fractures increased when diagnosed with DECT in addition to SECT compared to SECT alone. Furthermore, there was also an increase in inter-rater reliability, intra-rater reliability, and diagnostic accuracy. These findings were similarly observed even in the group with less years of medical experience, demonstrating that DECT can be a valuable tool in the diagnosis of sacral fractures.\u003c/p\u003e \u003cp\u003eWith the advent of an aging society, the number of patients with FFP is increasing rapidly worldwide. These fractures often occur as a result of low-energy trauma such as falls against a background of osteoporosis. Hence, they are fractures that anyone involved in medical treatment may encounter in the future, regardless of the scale of the hospital. Initially, when the concept of FFP was proposed, surgical treatment was considered preferable in all cases in fracture types with high instability (Rommens\u0026rsquo; FFP classification type III and IV) [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. In recent years, there have been more reports of conservative treatment being chosen as the primary option, regardless of the fracture type of FFP [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Accurate and reliable assessment of fracture type is essential for successful conservative treatment in FFP. If posterior element injuries are overlooked, the fracture type may be underestimated. Inappropriate treatment of such cases could lead to progression of the fracture type. This tendency for fracture types to progress easily is a characteristic of FFP and is one of the reasons why treatment is challenging [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. There are some reports indicate that Type III and IV cases will be more likely to require surgery ultimately than Type I and II cases [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e], and preventing progression of fracture type is clearly linked to the prognosis of FFP treatment. Among the components of the posterior elements of the pelvic ring, sacral fractures are particularly difficult to diagnoses. It is known that the sacral fractures are often overlooked when diagnosed only by X ray photographs [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], and that the diagnostic rate is not 100% even when evaluated with SECT [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Therefore, accurate diagnosis of sacral fractures is crucial in the treatment of FFP, and we consider imaging modalities that enable this diagnosis are highly valuable.\u003c/p\u003e \u003cp\u003eSECT is a useful imaging modality that can captures large areas quickly and reveals the three-dimensional structure of organs. It provides much more information compared to plain X-ray photograph. In cases of FFP, SECT is generally performed in all cases [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. In this study, when diagnosis of sacral fracture was made using only SECT, the accuracy rate was only 70-71.1% in the inexperienced group and 84.4\u0026ndash;85.6% in the experienced group. Similar to other reports, the diagnostic rate for sacral fractures using only SECT was far from 100%. Furthermore, this study also revealed that the accuracy rate varied significantly with the surgeon's years of experience. Inter-rater and intra-rater reliability were not very high, suggesting that X-ray photograph and SECT alone may be inadequate to determine an accurate diagnosis of FFP depending on the case. To obtain more detailed information, it is necessary to use contrast medium or increase the X-ray dose. However, there are concerns about physical invasion and increased radiation exposure to the patient in such cases. Although SECT can be performed quickly and has better diagnostic capabilities than X-ray photograph, we believe that imaging modalities with greater diagnostic accuracy are desirable for reliably diagnosing the fracture type of FFP.\u003c/p\u003e \u003cp\u003eThere's no doubt that MRI is extremely useful imaging modality in diagnosing fractures. Specifically, it is the most effective in diagnosing fresh vertebral compression fractures [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Additionally, MRI is highly useful in identifying incomplete fractures with intact cortical bone continuity, and it is known to have a higher detection rate for sacral fractures compared to SECT [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. MRI, which can detect sacral fractures with high accuracy, is very useful when diagnosing FFP. However, it is difficult to perform MRI in all cases where fractures are suspected due to several factors. The first factor is the patient's background. If a patient has metal in their body following cardiology or neurosurgical treatment, or if the patient cannot tolerate the examination itself due to claustrophobia or dementia, diagnosis must be conducted without using MRI. The second factor is the issue of medical costs. Due to certain costs, it is not practical to perform MRI in every suspected fracture case. Although MRI is effective tool for diagnosing sacral fractures, it cannot be performed urgently in every suspected case. Therefore, an alternative imaging modality to MRI would be beneficial.\u003c/p\u003e \u003cp\u003eDECT is an imaging modality that can be rapidly performed concurrently with SECT without increasing radiation exposure, and it is utilized in various fields. In the field of orthopedic surgery, images processed to suppress calcium and emphasize water are primarily used. In this setting, edema within the bone marrow is depicted distinctly as high-water density area, which is considered useful for diagnosing conditions such as fresh vertebral compression fractures and incomplete fractures with maintained cortical bone continuity [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. This study revealed that using DECT improves the accuracy of diagnosing sacral fractures. Notably, even for the inexperienced group, who are relatively unfamiliar with interpreting CT images, the addition of DECT greatly increased diagnostic accuracy, making it comparable to that of the experienced group. These results suggest that DECT clearly visualizes sacral fractures to the extent that anyone can diagnose them. Additionally, improved intra- and inter-rater reliability suggests that DECT is a highly reproducible examination in the diagnosis of sacral fractures. A major advantage of DECT is that accurate classification of FFP enables rapid determination of treatment strategies. Furthermore, we believe that DECT is also good usability imaging modality because it can be used for cases that are difficult to perform MRI and is not different from SECT in terms of cost. In this study, diagnoses were based solely on imaging. However, in actual clinical practice, detailed medical history and physical examinations are conducted before imaging, which should bring diagnostic accuracy closer to 100%. The results of this study suggest that using DECT to diagnose sacral fractures is a very effective method. Ultimately, we are considering performing DECT simultaneously with SECT in all cases of suspected fracture in our institution.\u003c/p\u003e \u003cp\u003eDECT is a rapid and useful imaging modality with a high rate of detecting fractures. However, there is a limitation that prevents imaging on CT devices that do not support DECT imaging. As it is impossible to retrofit this capability later, it is desirable for CT equipment capable of DECT imaging to become more widespread in many facilities in the future. It is crucial to inform the doctors responsible for the initial treatment beforehand to perform CT scan under DECT imaging conditions from the outset if a fracture is suspected. This is because once a scan is performed under SECT imaging conditions, it cannot be reconstructed into DECT images later.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eCombining DECT with SECT improved the detection capability and intra- and inter-rater reliability for sacral fractures. Furthermore, the high diagnostic accuracy achieved regardless of the observers' years of experience suggests that DECT could be a highly useful imaging modality as an alternative to MRI for diagnosing sacral fractures.\u003c/p\u003e "},{"header":"Declarations ","content":"\u003cp\u003e\u003cstrong\u003eData availability\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe original dataset generated during the current study is available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the appropriate Institutional Review Board (approval number: R5-41), and the study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no conflict of interest.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eRommens PM, Hofmann A. Focus on fragility fractures of the pelvis. Eur J Trauma Emerg Surg. 2021;47(1):1-2. https://doi.org/10.1007/s00068-020-01550-7\u003c/li\u003e\n\u003cli\u003eRommens PM, Hofmann A. The FFP-classification: From eminence to evidence. Injury. 2023;54 Suppl 3:S10-S19. https://doi.org/10.1016/j.injury.2021.09.016\u003c/li\u003e\n\u003cli\u003eSivapathasuntharam D, Smith G, Master MA, Bates P. Fragility fractures of the pelvis in the older population. Age Ageing. 2022;1;51(3):afac063. https://doi.org/10.1093/ageing/afac063\u003c/li\u003e\n\u003cli\u003eKannus P, Parkkari J, Niemi S, Siev\u0026auml;nen H. Low-Trauma Pelvic Fractures in Elderly Finns in 1970-2013. Calcif Tissue Int. 2015;97:577\u0026ndash;80. https://doi.org/10.1007/s00223-015-0056-8\u003c/li\u003e\n\u003cli\u003eBenzinger P, Becker C, Kerse N, Bleibler F, Gisela B\u0026uuml;chele G, Icks A, Rapp K. Pelvic fracture rates in community-living people with and without disability and in residents of nursing homes. J Am Med Dir Assoc. 2013;14:673\u0026ndash;8. https://doi.org/10.1016/j.jamda.2013.03.012\u003c/li\u003e\n\u003cli\u003eBanierink H, Duis KT, Prijs J, Wendt KW, Stirler VMA, Helden SH, Nijveldt RJ, Boomsma MF, E Heineman E, Reininga IHF, IJpma FFA. What is the long-term clinical outcome after fragility fractures of the pelvis? - A CT-based cross-sectional study. Injury. 2022;53(2):506-13. https://doi.org/10.1016/j.injury.2021.09.056\u003c/li\u003e\n\u003cli\u003eMaier GS, Kolbow K, Lazovic D, Horas K, Roth KE 4, Seeger JB 5, Uwe Maus U. Risk factors for pelvic insufficiency fractures and outcome after conservative therapy. Arch Gerontol Geriatr. 2016;67:80-5. https://doi.org/10.1016/j.archger.2016.06.020\u003c/li\u003e\n\u003cli\u003eRommens PM, Hofmann A. Comprehensive classification of fragility fractures of the pelvic ring: Recommendations for surgical treatment. Injury. 2013 Dec;44(12):1733-44. https://doi.org/10.1016/j.injury.2013.06.023\u003c/li\u003e\n\u003cli\u003eRommens PM, Ossendorf C, Philip Pairon P, Dietz SO, Wagner D, Hofmann A. Clinical pathways for fragility fractures of the pelvic ring: personal experience and review of the literature. J Orthop Sci. 2015;20(1):1-11. https://doi.org/10.1007/s00776-014-0653-9\u003c/li\u003e\n\u003cli\u003eRommens PM, Arand C, Hofmann A, Wagner D. When and How to Operate Fragility Fractures of the Pelvis? Indian J Orthop. 2019;53(1):128-37. https://doi.org/10.4103/ortho.IJOrtho_631_17\u003c/li\u003e\n\u003cli\u003eHenes FO, N\u0026uuml;chtern JV, Groth M, Habermann CR, Regier M, Rueger JM, Adam G, Gro\u0026szlig;terlinden LG. Comparison of diagnostic accuracy of Magnetic Resonance Imaging and Multidetector Computed Tomography in the detection of pelvic fractures. Eur J Radiol. 2012 Sep;81(9):2337-42. https://doi.org/10.1016/j.ejrad.2011.07.012\u003c/li\u003e\n\u003cli\u003eOberkircher L, Ruchholtz S, Rommens PM, Hofmann A, B\u0026uuml;cking B, Kr\u0026uuml;ger A. Osteoporotic Pelvic Fractures. Dtsch Arztebl Int. 2018;115(5):70-80. https://doi.org/10.3238/arztebl.2018.0070\u003c/li\u003e\n\u003cli\u003eRommens PM, Boudissa M, Kr\u0026auml;mer S, Kisilak M, Hofmann A, Wagner D. Operative treatment of fragility fractures of the pelvis is connected with lower mortality. A single institution experience. PLoS One. 2021;16(7):e0253408. https://doi.org/10.1371/journal.pone.0253408\u003c/li\u003e\n\u003cli\u003eCabarrus MC, Ambekar A, Lu Y, Link TM. MRI and CT of insufficiency fractures of the pelvis and the proximal femur. AJR Am J Roentgenol. 2008;191(4):995-1001. https://doi.org/10.2214/AJR.07.3714\u003c/li\u003e\n\u003cli\u003eFern\u0026aacute;ndez-P\u0026eacute;rez GC, Fraga Pi\u0026ntilde;eiro C, O\u0026ntilde;ate Miranda M, D\u0026iacute;ez Blanco M, Mato Cha\u0026iacute;n J, Collazos Mart\u0026iacute;nez MA. Dual-energy CT: Technical considerations and clinical applications. Radiologia (Engl Ed). 2022;64(5):445-455. https://doi.org/10.1016/j.rxeng.2022.06.003\u003c/li\u003e\n\u003cli\u003eAkisato K, Nishihara R, Okazaki H, Masuda T, Hironobe A, Ishizaki H, Shota K, Yamaguchi H, Funama Y. Dual-Energy CT of Material Decomposition Analysis for Detection with Bone Marrow Edema in Patients with Vertebral Compression Fractures. Acad Radiol. 2020;27(2):227-232. https://doi.org/10.1016/j.acra.2019.02.015\u003c/li\u003e\n\u003cli\u003ePalm HG, Lang P, Hackenbroch C, Sailer L, Friemert B. Dual-energy CT as an innovative method for diagnosing fragility fractures of the pelvic ring: a retrospective comparison with MRI as the gold standard. Arch Orthop Trauma Surg. 2020;140(4):473-480. https://doi.org/10.1007/s00402-019-03283-8\u003c/li\u003e\n\u003cli\u003eKoo H, Leveridge M, Thompson C, Zdero R, Bhandari M, Kreder HJ, Stephen D, McKee MD, Schemitsch EH. Interobserver reliability of the young-burgess and tile classification systems for fractures of the pelvic ring. J Orthop Trauma. 2008;22(6):379-84. https://doi.org/10.1097/BOT.0b013e31817440cf\u003c/li\u003e\n\u003cli\u003eGwet KL. Handbook of inter-rater reliability. The definitive guide to measuring the extent of agreement among raters. 4th edition; 2014. Gaithersburg: Advanced Analytics; 247-51.\u003c/li\u003e\n\u003cli\u003eKanda Y. Investigation of the freely available easy-to-use software \u0026apos;EZR\u0026apos; for medical statistics. Bone Marrow Transplant. 2013;48(3):452-8. https://doi.org/10.1038/bmt.2012.244\u003c/li\u003e\n\u003cli\u003eLandis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159-74.\u003c/li\u003e\n\u003cli\u003eOda T, Kitada S, Hirase H, Takada Y, Iwasa K, Niikura T. Evaluation of a treatment protocol based on conservative therapy for fragility fractures of the pelvis. Eur J Trauma Emerg Surg. 2024 Feb 23. Online ahead of print. https://doi.org/10.1007/s00068-024-02469-z\u003c/li\u003e\n\u003cli\u003eHotta K, Kobayashi T. Functional treatment strategy for fragility fractures of the pelvis in geriatric patients. Eur J Trauma Emerg Surg. 2021;47(1):21-7. https://doi.org/10.1007/s00068-020-01484-0\u003c/li\u003e\n\u003cli\u003eRommens PM, Arand C, Hopf JC, Mehling I, Dietz SO, Wagner D. Progress of instability in fragility fractures of the pelvis: An observational study. Injury. 2019;50(11):1966-1973. https://doi.org/10.1016/j.injury.2019.08.038\u003c/li\u003e\n\u003cli\u003eRommens PM, Hopf JC, Arand C, Handrich K, Boudissa M, Wagner D. Prospective assessment of key factors influencing treatment strategy and outcome of fragility fractures of the pelvis (FFP). Eur J Trauma Emerg Surg. 2022;48(4):3243-3256. https://doi.org/10.1007/s00068-022-01887-1\u003c/li\u003e\n\u003cli\u003eNuber S, Ritter B, Fenwick A, F\u0026ouml;rch S, Wanzl M, Nuber M, Mayr E. Midterm follow-up of elderly patients with fragility fractures of the pelvis: A prospective cohort-study comparing operative and non-operative treatment according to a therapeutic algorithm. Injury. 2022;53(2):496-505. https://doi.org/10.1016/j.injury.2021.09.044\u003c/li\u003e\n\u003cli\u003eLyders EM, Whitlow CT, Baker MD, Morris PP. Imaging and treatment of sacral insufficiency fractures. AJNR Am J Neuroradiol. 2010;31(2):201-10. https://doi.org/10.3174/ajnr.A1666\u003c/li\u003e\n\u003cli\u003eChou SH, LeBoff MS. Vertebral Imaging in the Diagnosis of Osteoporosis: a Clinician\u0026apos;s Perspective. Curr Osteoporos Rep. 2017;15(6):509-520. https://doi.org/10.1007/s11914-017-0404-x\u003c/li\u003e\n\u003cli\u003eKaup M, Wichmann JL, Scholtz JE, Beeres M, Kromen W, Albrecht MH, Lehnert T, Boettcher M, Vogl TJ, Bauer RW. Dual-Energy CT-based Display of Bone Marrow Edema in Osteoporotic Vertebral Compression Fractures: Impact on Diagnostic Accuracy of Radiologists with Varying Levels of Experience in Correlation to MR Imaging. Radiology. 2016;280(2):510-9. https://doi.org/10.1148/radiol.2016150472\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-trauma-and-emergency-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejot","sideBox":"Learn more about [European Journal of Trauma and Emergency Surgery](http://link.springer.com/journal/68)","snPcode":"68","submissionUrl":"https://submission.nature.com/new-submission/68/3","title":"European Journal of Trauma and Emergency Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Sacral fracture, Dual- energy CT, Inter-rater reliability, Intra-rater reliability, Fragility fractures of the pelvis","lastPublishedDoi":"10.21203/rs.3.rs-4859889/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4859889/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eEvaluating sacral fractures is crucial in fragility fractures of the pelvis. Dual-energy CT (DECT) is considered useful for diagnosing unclear fractures on single-energy CT (SECT). This study aims to investigate the effectiveness of DECT in diagnosing sacral fractures.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThirty cases suspected of sacral fractures who underwent SECT, DECT, and MRI, and were diagnosed for the presence of fractures by three inexperienced surgeons (group I) and three experienced surgeons (group E). Diagnoses were made initially using SECT (pre-DECT) and then reassessed including DECT (post-DECT). This process was repeated twice. Presence of fractures was determined based on MRI. Sensitivity, specificity, inter-rater and intra-rater reliability, and diagnostic accuracy were calculated. Diagnostic accuracy was statistically compared between two groups.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eSensitivity was 0.73 in pre-DECT and 0.9 in post-DECT, while specificity was 0.83 in pre-DECT and 0.91 in post-DECT. Sensitivity significantly improved with the addition of DECT (McNemar test: p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Intra-rater reliability (Fleiss' kappa coefficient) was 0.44 in pre-DECT and 0.76 in post-DECT. Inter-rater reliability (Cohen's kappa coefficient) was 0.6 in pre-DECT and 0.81 in post-DECT. Diagnostic accuracy was significantly lower in group I than group E in pre-DECT (P\u0026thinsp;=\u0026thinsp;0.019, 0.048), but there was no significant difference between two groups in post-DECT.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eCombined use of DECT with SECT improved the detection rate of sacral fractures and enhanced intra-rater and inter-rater reliability. High diagnostic accuracy was achieved regardless of the observer's experience. These results indicate that DECT is a useful imaging modality for diagnosing sacral fractures.\u003c/p\u003e","manuscriptTitle":"A multi-observer study on the effectiveness of Dual-energy CT in diagnosing sacral fractures: assessment of diagnostic accuracy and intra- and inter-rater reliabilities","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-09-12 13:01:45","doi":"10.21203/rs.3.rs-4859889/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-10-04T21:38:35+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-28T16:08:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"317930569669500288341367368862892053495","date":"2024-08-15T05:57:33+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-08-12T19:50:44+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-08-12T19:48:46+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-08-07T07:05:03+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Journal of Trauma and Emergency Surgery","date":"2024-08-05T07:05:37+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-trauma-and-emergency-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejot","sideBox":"Learn more about [European Journal of Trauma and Emergency Surgery](http://link.springer.com/journal/68)","snPcode":"68","submissionUrl":"https://submission.nature.com/new-submission/68/3","title":"European Journal of Trauma and Emergency Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"e0979f40-21ba-4c24-a5f2-28148df865ce","owner":[],"postedDate":"September 12th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-01-27T16:00:10+00:00","versionOfRecord":{"articleIdentity":"rs-4859889","link":"https://doi.org/10.1007/s00068-024-02673-x","journal":{"identity":"european-journal-of-trauma-and-emergency-surgery","isVorOnly":false,"title":"European Journal of Trauma and Emergency Surgery"},"publishedOn":"2025-01-24 15:57:13","publishedOnDateReadable":"January 24th, 2025"},"versionCreatedAt":"2024-09-12 13:01:45","video":"","vorDoi":"10.1007/s00068-024-02673-x","vorDoiUrl":"https://doi.org/10.1007/s00068-024-02673-x","workflowStages":[]},"version":"v1","identity":"rs-4859889","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4859889","identity":"rs-4859889","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}