Gastrointestinal Radiology Research Articles

Heterogeneity of definition of upper gastrointestinal tract in different guidelines of Crohn's disease: A scoping review.

Crohn's Disease (CD) can affect any part of the gastrointestinal (GI) tract, including the upper GI tract (UGIT). However, the definitions and classifications of upper GI CD (UGICD) vary. We conducted a scoping review to explore how UGIT and UGICD are defined and to assess the heterogeneity of these definitions in published CD guidelines, aiming to inform future initiatives for harmonizing definitions. We conducted a search of MEDLINE and Embase for English-language guidelines on CD that mentioned upper GI-related terms in the titles, abstracts, or keywords from inception until 26 July 2024. Definitions of UGIT and UGICD were summarized descriptively. Of 1132 citations, only 19 records met our inclusion criteria. Only eight were identified as CD guidelines. None of them focuses on UGICD. Among these, five diagnostic guidelines explicitly mentioned "upper GI" in their abstracts. Only the joint European Crohn's and Colitis Organisation and European Society of Gastrointestinal and Abdominal Radiology guidelines clearly defined the UGIT. Most guidelines mentioned UGI terms related to upper endoscopy or biopsy only. It was unclear whether these guidelines typically included the esophagus, stomach, and duodenum in the definition of UGICD while excluding the distal small intestine. Although the latest guideline related to pediatric-onset IBD cited the 2011 Paris classification, none of the three guidelines published after that explicitly mentioned the proposed subdivided location of the upper disease. There is a lack of consistent reporting in defining UGICD according to disease location. It is unclear whether there is a consensus on excluding the small intestine beyond the duodenum. Additionally, there is no indication that the subdivided location of UGIT was considered in CD guideline development. Greater consistency in definitions would aid in diagnosis, clinical care, epidemiological research and inclusion into clinical trials. These findings underscore the need for developing a framework to standardize the classification of UGICD, especially for clinical trials.

Imaging of peritoneal metastases of ovarian and colorectal cancer: joint recommendations of ESGAR, ESUR, PSOGI, and EANM.

Diagnostic imaging of peritoneal metastases in ovarian and colorectal cancer remains pivotal in selecting the most appropriate treatment and balancing clinical benefit with treatment-related morbidity and mortality. To address the challenges related to diagnostic imaging and detecting and reporting peritoneal metastatic spread, a joint guideline was created by the European Society of Gastrointestinal and Abdominal Radiology (ESGAR), European Society of Urogenital Radiology (ESUR), Peritoneal Surface Oncology Group International (PSOGI), and European Association of Nuclear Medicine (EANM). A targeted literature search was performed and consensus recommendations were proposed using Delphi questionnaires and a five-point Likert scale. A total of three Delphi rounds were performed. Consensus was reached on the position of diagnostic imaging for assessment of operability, treatment response monitoring, and follow-up of peritoneal metastases, optimal imaging modality and their technical imaging requirements depending on the indication and how to optimise communication of imaging results by the report and multidisciplinary board discussion. The complete list of recommendations is provided. These expert consensus statements aim to guide appropriate indications, acquisition, interpretation, and reporting of imaging for operability assessment, treatment response monitoring, and follow-up of peritoneal metastases in ovarian and colorectal cancer patients. Question Staging peritoneal metastases (PM) helps toguide clinical decision-making for colorectal and ovarian cancer patients. How can we optimise the use of imaging techniques to assess PM? Findings Imaging plays a crucial role in the detection, operability assessment, treatment response monitoring, and follow-up of peritoneal metastases in colorectal and ovarian cancer patients. Clinical relevance These expert consensus statements aim to guide appropriate indication, acquisition, interpretation, and reporting of imaging for operability assessment, treatment response monitoring, and follow-up of peritoneal metastases in ovarian and colorectal cancer patients.

Whether the Liver-to-Portal Vein Ratio is Applicable for Evaluating the European Society of Gastrointestinal and Abdominal Radiology Hepatobiliary Phase in Gd-EOB-DTPA-Enhanced MRI?

This study aimed to verify whether the Liver-to-portal Ratio (LPR) can assess the adequacy of the Hepatobiliary Phase (HBP) for patients with different liver functions. A total of 125 patients were prospectively enrolled in the study and graded into the non-cirrhosis group (45), Child-Pugh A group (40), and Child- Pugh B/C group (40). The LPR on HBP was calculated after eight HBPs were obtained within 5-40 minutes. The adequate HBP was determined according to the 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus statement. The differences in LPR and lesions' conspicuity between 10-min HBP and adequate HBP were analyzed by paired t-test and Wilcoxon signed-rank test, respectively. The chisquare test was used to test the difference in proportion with LPR larger than 1.462 between 10-min HBP and adequate HBP. The differences in LPR and lesions' conspicuity between 10-min HBP and adequate HBP were significant in Child-Pugh A and Child-Pugh B/C groups (P < 0.05), except for the non-cirrhosis group (P > 0.05). The differences in proportion with LPR larger than 1.462 between 10-min HBP and adequate HBP were not statistically significant in all groups (all P > 0.05). The adequate HBP obtained according to the 2016 ESGAR consensus statement could provide larger LPR and better lesions' conspicuity than 10- min HBP, especially for cirrhotic patients; however, the efficacy of using an LPR cutoff of 1.462 as the standard of the adequate HBP may be compromised in patients with cirrhosis.

MR staging of rectal cancer: Comparison between the 2012 and 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guidelines

PurposeTo compare the adherence of the interpretation and reporting staging system, respectively proposed in the 2012 and 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guidelines for Magnetic Resonance Imaging (MRI) staging of rectal cancer, focusing on the improvement offered by the criteria introduced by 2016 ESGAR guidelines. MethodFifty-six patients affected by rectal cancer were included; 25/56 patients underwent upfront surgery; 31 underwent to neo-adjuvant chemo-radiotherapy before surgery. All patients underwent 3 T MRI examination for local staging. All MR exams were evaluated by two radiologists with 20- and 4-years’ experience, who were blinded to each other; the T and N stages, the Mesorectal Fascia (MRF) status and the Extramural Vascular Invasion (EMVI) were assessed according to both 2012 and 2016 ESGAR guidelines. The correlation between radiological and pathological findings, as well as the MRI staging were evaluated. ResultsAs to the expert reviewer, no significant differences were found by comparing the MR T and N stages, T and N restaging, MRF status and EMVI according to 2012 and 2016 ESGAR guidelines. As to the 4-years’ experience radiologist the MR staging agreement between 2012 and 2016 guidelines was “moderate” in N-stage evaluation and “fair” in T-restaging evaluation. No significant discrepancies were found for other parameters. ConclusionsMRI is a reliable method in rectal cancer staging/restaging. The assessment of T-restaging is improved by adopting the 2016 ESGAR guidelines, especially for non-expert readers; this result could be justified by the introduction of diffusion-weighted imaging. On the contrary, the newest guidelines do not improve the diagnostic performance in assessing nodal staging and restaging.

A retrieval-augmented chatbot based on GPT-4 provides appropriate differential diagnosis in gastrointestinal radiology: a proof of concept study

BackgroundWe investigated the potential of an imaging-aware GPT-4-based chatbot in providing diagnoses based on imaging descriptions of abdominal pathologies.MethodsUtilizing zero-shot learning via the LlamaIndex framework, GPT-4 was enhanced using the 96 documents from the Radiographics Top 10 Reading List on gastrointestinal imaging, creating a gastrointestinal imaging-aware chatbot (GIA-CB). To assess its diagnostic capability, 50 cases on a variety of abdominal pathologies were created, comprising radiological findings in fluoroscopy, MRI, and CT. We compared the GIA-CB to the generic GPT-4 chatbot (g-CB) in providing the primary and 2 additional differential diagnoses, using interpretations from senior-level radiologists as ground truth. The trustworthiness of the GIA-CB was evaluated by investigating the source documents as provided by the knowledge-retrieval mechanism. Mann–Whitney U test was employed.ResultsThe GIA-CB demonstrated a high capability to identify the most appropriate differential diagnosis in 39/50 cases (78%), significantly surpassing the g-CB in 27/50 cases (54%) (p = 0.006). Notably, the GIA-CB offered the primary differential in the top 3 differential diagnoses in 45/50 cases (90%) versus g-CB with 37/50 cases (74%) (p = 0.022) and always with appropriate explanations. The median response time was 29.8 s for GIA-CB and 15.7 s for g-CB, and the mean cost per case was $0.15 and $0.02, respectively.ConclusionsThe GIA-CB not only provided an accurate diagnosis for gastrointestinal pathologies, but also direct access to source documents, providing insight into the decision-making process, a step towards trustworthy and explainable AI. Integrating context-specific data into AI models can support evidence-based clinical decision-making.Relevance statementA context-aware GPT-4 chatbot demonstrates high accuracy in providing differential diagnoses based on imaging descriptions, surpassing the generic GPT-4. It provided formulated rationale and source excerpts supporting the diagnoses, thus enhancing trustworthy decision-support.Key points• Knowledge retrieval enhances differential diagnoses in a gastrointestinal imaging-aware chatbot (GIA-CB).• GIA-CB outperformed the generic counterpart, providing formulated rationale and source excerpts.• GIA-CB has the potential to pave the way for AI-assisted decision support systems.Graphical

Comprehensive CT Imaging Analysis of Primary Colorectal Squamous Cell Carcinoma: A Retrospective Study.

The aim of this study was to evaluate the findings of CT scans in patients with pathologically confirmed primary colorectal squamous-cell carcinoma (SCC). The clinical presentation and CT findings in eight patients with pathologically confirmed primary colorectal squamous-cell carcinoma were retrospectively reviewed by two gastrointestinal radiologists. Hematochezia was the most common symptom (n = 5). The tumors were located in the rectum (n = 7) and sigmoid colon (n = 1). The tumors showed circumferential wall thickening (n = 4), bulky mass (n = 3), or eccentric wall thickening (n = 1). The mean maximal wall thickness of the involved segment was 29.1 mm ± 13.4 mm. The degree of tumoral enhancement observed via CT was well enhanced (n = 4) or moderately enhanced (n = 4). Necrosis within the tumor was found in five patients. The mean total number of metastatic lymph nodes was 3.1 ± 3.3, and the mean short diameter of the largest metastatic lymph node was 16.6 ± 5.7 mm. Necrosis within the metastatic node was observed in six patients. Invasions to adjacent organs were identified in five patients (62.5%). Distant metastasis was detected in only one patient. In summary, primary SCCs that arise from the colorectum commonly present as marked invasive wall thickening or a bulky mass with heterogeneous well-defined enhancement, internal necrosis, and large metastatic lymphadenopathies.

High prevalence of fatty liver and its association with metabolic syndrome among rural adults with chronic hepatitis C: Implications for primary healthcare

BackgroundChronic hepatitis C (CHC) virus infection is a global health concern that is associated with significant liver-related morbidity and mortality. Owing to the inflammatory pathway, CHC can causefatty liver, liver cirrhosis, and liver cancer and is associated with cardiometabolic diseases, such as hypertension and diabetes. Fatty liver is associated with metabolic disorders, cardiovascular diseases, diabetes, and liver cancer. Hence, the early detection of fatty liver through noninvasive screening in adults with CHC is important in primary healthcare settings. This study aimed to explore the prevalence of fatty liver and its association with metabolic syndrome amongrural adults with CHC.MethodsThis was a series of cohort studies related to the elimination of the CHC burden around the western coastal Yunlin County, Taiwan, between August 2018 and July 2021. A cross-sectional study was conducted after hepatitis C virus RNA confirmation in a hepatitis C- endemic area. A gastrointestinal physician or radiologist assessed fatty liver by ultrasonography. Fatty liver was classified into four grades: normal, mild, moderate, and severe. Three liver enzyme biomarkers were identified. According to the Taiwan national standard, metabolic syndrome was defined based on the presence of three or more of the five abnormal biomarkers, including increased waist circumference, elevated blood pressure, elevated fasting blood glucose level, elevated triglyceride level, and low high-density lipoprotein cholesterol level.ResultsA total of 256 rural adults with CHC were enrolled. The mean age of the participants was 67.5 (standard deviation = 11.8) years, with a low educational level. High prevalence of fatty liver (79%), central obesity (54.3%), elevated blood pressure (55.5%),elevated fasting blood glucose (FBG) level (44.9%), and metabolic syndrome (37.9%) were observed.The results showed that adults with CHC with moderate to severe fatty liver were significantly associated with an increased risk of increased waist circumference (P < 0.001), increased blood pressure (P < 0.001), low high-density lipoprotein cholesterol level (P < 0.05), and elevated liver enzyme biomarker levels (all P < 0.05) after adjusting for age, sex, and educational level. Furthermore, adults with CHC with moderate to severe fatty liver were significantly associated with a greater risk of metabolic syndrome (odds ratio = 2.85, 95% confidence interval = 1.66 to 4.92).ConclusionsThe findings demonstrate a high prevalence of fatty liver in rural adults with CHC, which is significantly associated with obesity, metabolic syndrome, and elevated liver biomarker levels. Clinicians and primary healthcare providers must encourage patients with CHC to receive antiviral therapy combined with weight loss management and lifestyle modification, allowing general improvements in their liver and cardiometabolic health.

Prediction of bowel necrosis by reduced bowel wall enhancement in closed-loop small bowel obstruction: Quantitative methods

PurposeTo assess diagnostic performance and reproducibility of reduced bowel wall enhancement evaluated by quantitative methods using CT to identify bowel necrosis among closed-loop small bowel obstruction (CL-SBO) patients. MethodsThis retrospective single-center study included patients who diagnosed with CL-SBO caused by adhesion or internal hernia during January 2016 and May 2022. Patients were divided into necrotic group (n = 41) and non-necrotic group (n = 67) according to surgical exploration and postoperative pathology. Two doctors independently measured the attenuation of bowel wall and consensus was reached through panel discussion with a third gastrointestinal radiologist. Reduced bowel wall enhancement was assessed by four quantitative methods. Univariate analyses were used to evaluate the association between each method and bowel necrosis, and kappa/intraclass correlation coefficient values were used to assess interobserver agreement. Diagnostic performance parameters were calculated for each method. ResultsReduced bowel wall enhancement in arterial phase (OR 8.98, P < 0.0001), reduced bowel wall enhancement in portal phase (OR 16.84, P < 0.001), adjusted reduced bowel wall enhancement in arterial phase (OR 29.48, P < 0.001), adjusted reduced bowel wall enhancement in portal phase (OR 145.69, P < 0.001) were significantly associated with bowel necrosis. Adjusted reduced bowel wall enhancement in portal phase had the best diagnostic performance (AUC: 0.92; Youden index: 0.84; specificity: 94.03 %) and interobserver agreement (kappa value of 0.59–0.73) to predict bowel necrosis. ConclusionWhen assessing reduced bowel enhancement to predict bowel necrosis among CL-SBO patients, using unenhanced CT images and proximal dilated loop as standard references in portal phase is the most accurate quantitative method among those tested.

Increased Attenuation of Intestinal Contents at CT Indicates Bowel Necrosis in Closed-Loop Small Bowel Obstruction.

Background Preoperative recognition of irreversible bowel necrosis is important, as it provides valuable guidance for surgical strategy selection but also may inform perioperative risk assessment and communication. Few studies have focused on the association between CT signs and bowel necrosis. Purpose To assess the diagnostic accuracy of CT signs to predict bowel necrosis in patients with closed-loop small bowel obstruction (CL-SBO). Materials and Methods This retrospective single-center study included patients who were surgically confirmed to have CL-SBO caused by adhesion or internal hernia between January 2016 and May 2022. Necrosis was determined based on surgical exploration and postoperative pathologic examination. Two radiologists independently reviewed CT signs by both subjective visual assessment and objective measurement. Disagreements were resolved in consensus with a third gastrointestinal radiologist. Univariable and multivariable analyses were used to assess the association between CT signs and bowel necrosis, and Cohen κ was used to assess interobserver agreement. Sensitivity and specificity were calculated for each CT sign. Results This study included 145 patients: 61 (42.1%) in the necrotic group (median age, 62 years [IQR, 51-71.5 years]; 37 [60.7%] women) and 84 (57.9%) in the nonnecrotic group (median age, 61.5 years [IQR, 51-68.8 years]; 51 [60.7%] women). Univariable analysis and multivariable analysis showed that increased attenuation of intestinal contents and increased attenuation of intestinal wall were independent predictors for bowel necrosis (odds ratio = 45.3 and 15.1; P = .001 and P < .001, respectively). Increased attenuation of intestinal contents and increased attenuation of intestinal wall had similar sensitivity (64% and 67%, respectively) and specificity (99% and 92%, respectively) for predicting bowel necrosis. However, interobserver agreement was better for assessing the contents than the wall (κ = 0.84 and 0.59, respectively). Conclusion Increased attenuation of intestinal contents was a highly specific CT sign with good reproducibility to predict bowel necrosis in CL-SBO. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Taourel and Zins in this issue.

P457 Small bowel involvement proximal to the terminal ileum is a major risk factor for intestinal resection in patients with small bowel Crohn’s disease

Abstract Background The current Montreal classification categorizes Crohn's disease (CD) with small bowel involvement into two groups: L1 and L3. The study aimed to investigate the significance of small bowel involvement proximal to the terminal ileum as a significant risk factor for intestinal resection. Methods We conducted a retrospective review of the medical records of Crohn's disease patients diagnosed between January 2001 and December 2020 at Seoul St. Mary's Hospital, St. Vincent Hospital, and Eunpyeong St. Mary's Hospital. The extent of small bowel involvement was independently assessed by two experienced gastrointestinal radiologists using conventional CT, CT enterography, or MR enterography at the time of diagnosis. The terminal ileum was defined as the distal ileal segment within 10 cm from the ileocecal valve and the jejunum was defined as the proximal 1/2 of the small intestine beyond the ligament of Treitz. Radiologic disease activity and fibrostenosis at the time of diagnosis were also scored as 0, 1, and 2 using Maglinte classification, respectively. Results Out of 617 CD patients, 346 were included in the study, while 271 were excluded due to radiologic noninvolvement of the small bowel, inadequate or missing radiologic data, initial diagnosis made at another institution, or diagnosis through surgery. Median age at diagnosis was 24 years (range 10-76) and 250 (72.3%) were male. The median follow-up duration was 53 months (4-201). During the follow-up period, 43 patients (12.4%) underwent intestinal resection. Small bowel involvement proximal to the terminal ileum was significantly associated with a higher cumulative risk of intestinal resection (15.4% vs. 3.5%, P=0.006). Neither jejunal involvement or colonic involvement (L3 vs. L1) showed a significant association with cumulative risk of intestinal resection (16.0% vs. 11.1%, P=0.222; 12.4% vs. 12.4%, P=0.773). Radiologic disease activity and fibrostenotic score at the time of diagnosis were significantly associated with the cumulative risk of intestinal resection, respectively (0% vs. 4.4% vs. 19.7%, P&amp;lt;0.001; 8.5% vs. 16.7% vs. 28.2%, P&amp;lt;0.001). Conclusion Small bowel involvement proximal to the terminal ileum was a major risk factor for requiring intestinal resection in patients with small bowel CD, while jejunal involvement was not. These findings suggest a need for subclassifying small bowel CD.

CT findings in idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) and comparison to other colitides.

The purpose of this study is to determine computed tomography (CT) findings that aid in differentiating idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) from other colitides. Retrospective review of histiologic proven cases of IMHMV (n = 12) with contrast enhanced CT (n = 11) and/or computed tomography angiography (CTA) (n = 9) exams. Control groups comprised of CT of infectious colitis (n = 13), CT of inflammatory bowel disease (IBD) (n = 12), and CTA of other colitides (n = 13). CT exams reviewed by 2 blinded gastrointestinal radiologists for maximum bowel wall thickness, enhancement pattern, decreased bowel wall enhancement, submucosal attenuation value, presence and location of IMV occlusion, peripheral mesenteric venous occlusion, dilated pericolonic veins, subjective IMA dilation, maximum IMA diameter, maximum peripheral IMA branch diameter, ascites, and mesenteric edema. Presence of early filling veins was an additional finding evaluated on CTA exams. Statistically significant CT findings of IMHMV compared to control groups included greater maximum bowel wall thickness, decreased bowel enhancement, IMV occlusion, and peripheral mesenteric venous occlusion (p < 0.05). Dilated pericolonic veins were seen more frequently in IMHMV compared to the infectious colitis group (64% versus 15%, p = 0.02). Additional statistically significant finding on CTA included early filling veins in IMHMV compared to the CTA control group (100% versus 46%, p = 0.008). IMHMV is a rare chronic non-thrombotic ischemia predominantly involving the rectosigmoid colon. CT features that may aid in differentiating IMHMV from other causes of left-sided colitis include marked bowel wall thickening with decreased enhancement, IMV and peripheral mesenteric venous occlusion or tapering, and early filling of dilated veins on CTA.

Survey of rectal cancer MRI technique and reporting tumour descriptors in the UK: a multi-centre British Society of Gastrointestinal and Abdominal Radiology (BSGAR) audit

To evaluate variation in magnetic resonance imaging (MRI) technique and reporting of rectal cancer staging examinations across the UK. A retrospective, multi-centre audit was undertaken of imaging protocols and information documented within consecutive MRI rectal cancer reports between March 2020 and August 2021, which were compared against American and European guidelines. Inclusion criteria included histologically proven rectal adenocarcinoma and baseline staging MRI rectum only. Fully anonymised data from 924 MRI reports by 78 radiologists at 24 centres were evaluated. Thirty-two per cent of radiologists used template reporting, but these reports offered superior documentation of 13 out of 18 key tumour features compared to free-text reports including T-stage, relation to peritoneal reflection and mesorectal fascia (MRF), nodal status, and presence of extramural venous invasion (EMVI; p<0.027 in each). There was no significant differences in the remaining five features. Across all tumour locations, the tumour relationship to the MRF, the presence of EMVI, and the presence of tumour deposits were reported in 79.5%, 85.6%, and 44% of cases, respectively, and tumour, nodal, and distant metastatic stage documented in 94.4%, 97.7%, and 78.3%. In low rectal tumours, the relationship to the anal sphincter complex was reported in only 54.6%. Considerable variation exists in rectal cancer MRI acquisition and reporting in this sample of UK centres. Inclusion of key radiological features in reports must be improved for risk stratification and treatment decisions. Template reporting is superior to free-text reporting. Routine adoption of standardised radiology practices should now be considered to improve standards to facilitate personalised precision treatment for patients to improve outcomes.

Focal loss of mural stratification as a radiological predictor for small bowel adenocarcinoma in Crohn's disease

AimPatients with Crohn's disease (CD) are at higher risk of small bowel adenocarcinoma (SBA). We aimed to identify radiological predictors of SBA in CD. MethodsWe conducted a retrospective case-control study at two tertiary inflammatory bowel disease centers and identified CD patients diagnosed with SBA between 2003 and 2019. Patients were matched with up to four controls. Pre-operative imaging (magnetic resonance imaging (MRI) or computed tomography (CT)) were reviewed by three gastrointestinal radiologists. ResultsNineteen patients with CD-associated SBA with a mean age of 54.9 and 32 matched controls were included. Mean length of small bowel involvement was 216 (± 188) mm in the SBA group versus 156 (± 167) mm in the control group (p = 0.76). Only 11.8 % of cases had a diagnosis of SBA made preoperatively. In univariate analysis, focal loss of mural stratification (odds ratio [OR], 11; 95%CI, 2.43–49.5, p = 0.002), and wall thickening (OR, 1.32; 95%CI, 1.05–1.66, p = 0.02) were significantly associated with SBA. After adjustment, focal loss of mural stratification was the only independent risk factor (OR, 11; 95 % CI, 2.43-49.5, p = 0.002). ConclusionsFocal loss of mural stratification was identified as a predictor of CD-associated SBA, which should be described in imaging reports and further validated.

PACT-UK (PAncreatic Cancer reporting Template–UK): a cross-specialty multi-institutional consensus panel development of a standardised radiological reporting proforma for pancreatic cancer

ObjectiveAppropriate staging of pancreatic cancer is essential to ensure patients are offered all treatment options. This multispecialty national collaborative consensus project aimed to develop a succinct radiological reporting template, using...

MRI in rectal cancer: An institutional real life analysis of technical parameters

MRI plays a key role in the preoperative staging of rectal cancers and choice of neoadjuvant radiochemotherapy. Yet, the acquisition and interpretation of rectum magnetic resonance imaging (MRI) turn out to be unequal, impacting patients'care. The present study aims at evaluating the quality of the acquisition of technical parameters of the rectal MRI performed by comparing them according to the various guidelines. The medical MRI reports of all consecutive patients with locally advanced rectal cancer treated in a curative intent, by preoperative RCT and completion surgery were retrospectively reviewed over two periods (January 2010-December 2014 and January 2018 and December 2020) according to international 2012 and 2016 ESGAR and 2017 SAR MRI recommendation reports. During the first period (69 MRI performed), 58% of these MRI abided by the recommendations and 75% of essential criteria could be found in 25.5% of MRI reportings. During the second period (73 MRI performed), the protocol used by 6.8% of MR images abided by the 2016 Society of Gastrointestinal and Abdominal Radiology(ESGAR) recommendations and 39.7% abided by the Society of Abdominal Radiology (SAR) recommendations. 75% of essential criteria could be found in 52.3% of MRI reportings and 90% of essential criteria could be found in 6.2% of MRI reportings. In an era of increasing individualized patient care and conservative treatment focused on tumour response and prognostic factors, the present study showed that compliance to MRI protocols and reporting guidelines needs improving to upgrade patient care.

Dynamic magnetic resonance imaging of the pelvic floor: Technical aspects

Dynamic magnetic resonance imaging (MRI) of the pelvic floor plays akey role in imaging complex pelvic floor dysfunction. High-quality examination is crucial for diagnostic benefit but can be technically challenging. The most important technical aspects (patient selection, patient preparation, MRI technology, MRI scan protocol, success control) for obtaining astate-of-the-art dynamic MRI of the pelvic floor are summarized. Review of the scientific literature on dynamic pelvic MR imaging with special consideration of the joint recommendations provided by the expert panels of European Society of Urogenital Radiology/European Society of Gastrointestinal and Abdominal Radiology (ESUR/ESGAR) in 2016 and Society of Abdominal Radiology (SAR) in 2019. Examination with at least 1.5 T and asurface coil after rectal instillation of ultrasound gel is clinical standard. Dynamic MRI in aclosed magnet with the patient in supine position is the most widespread technique. No clinically significant pathologies of the pelvic floor are missed compared to the sitting position in an open magnet. The minimum scan protocol should encompass static, high-resolution T2-imaging (i.e., T2-TSE) in three planes and dynamic sequences with high temporal resolution in sagittal (and possibly axial) plane (i.e., steady-state or balanced steady-state free precession) during squeezing, straining and evacuation. Detailed patient instruction and practicing prior to the scan improve patients' compliance and hence diagnostic quality. Atechnically flawless dynamic MRI of the pelvic floor according to these standards can provide information missed by other imaging modalities and hence alter therapeutic strategies.

470. DO RADIOLOGISTS ALWAYS USE ORAL CONTRAST DURING CT SCANNING FOR POST-ESOPHAGECTOMY ANASTOMOTIC LEAK: SURVEY OF PROTOCOLS IN THE UK

Abstract Background Anastomotic leak (AL) is a life-threatening complication following esophagectomy. Early and accurate diagnosis is key. Although computerized tomography (CT) scan is a widely employed diagnostic modality, there is no consensus on whether oral contrast should be used in addition to IV contrast. We sought to survey protocols regarding the use of oral contrast amongst specialist radiologists when using CT scan to diagnose AL. Methods An online questionnaire was sent to 27 consultant gastrointestinal (GI) radiologists with a subspecialist esophageal interest from 11 tertiary centres. Participants were primarily asked for their preferred imaging modality to diagnose AL, choice of contrast if a CT scan was used (assuming no contraindications for IV contrast) and an explanation for their preferred choice of investigation. Results The response rate was 96.3% (n = 26). Most participants (16 [61.5%]) used CT scan as first choice modality, while six (23.1%) used fluoroscopy and two (15.3%) used CT scan and fluoroscopy. With CT scan, half the participants preferred using both oral and IV contrast to IV contrast alone. No participants chose oral contrast alone. Some participants who used oral contrast felt it helped differentiate between normal post-surgical changes and true leaks. Limitations of using oral contrast included concerns of missed leaks involving the anterior aspect of the esophagus and lowered enhancement of the esophageal mucosa. Conclusion The majority of radiologists favor using oral contrast in addition to IV contrast for CT scan for suspected AL. In spite of this, practice is variable even amongst radiologists from the same unit. The lack of consensus emphasizes the need for further research to establish best practice and formulation of guidelines.

Comparison of Diatrizoate and Iohexol for Patient Acceptance and Fecal-Tagging Performance in Noncathartic CT Colonography.

The aim of this study was to compare diatrizoate and iohexol regarding patient acceptance and fecal-tagging performance in noncathartic computed tomography colonography. This study enrolled 284 volunteers with fecal tagging by either diatrizoate or iohexol at an iodine concentration of 13.33 mg/mL and an iodine load of 24 g. Patient acceptance was rated on a 4-point scale of gastrointestinal discomfort. Two gastrointestinal radiologists jointly analyzed image quality, fecal-tagging density and homogeneity, and residual contrast agent in the small intestine. The results were compared by the generalized estimating equation method. Patient acceptance was comparable between the 2 groups (3.95 ± 0.22 vs 3.96 ± 0.20, P = 0.777). The diatrizoate group had less residual fluid and stool than the iohexol group ( P = 0.019, P = 0.004, respectively). There was no significant difference in colorectal distention, residual fluid, and stool tagging quality between the 2 groups (all P 's > 0.05). The mean 2-dimensional image quality score was 4.59 ± 0.68 with diatrizoate and 3.60 ± 1.14 with iohexol ( P < 0.001). The attenuation of tagged feces was 581 ± 66 HU with diatrizoate and 1038 ± 117 HU with iohexol ( P < 0.001). Residual contrast agent in the small intestine was assessed at 55.3% and 62.3% for the diatrizoate group and iohexol group, respectively ( P = 0.003). Compared with iohexol, diatrizoate had better image quality, proper fecal-tagging density, and more homogeneous tagging along with comparable excellent patient acceptance, and might be more suitable for fecal tagging in noncathartic computed tomography colonography.

MRI for nodal restaging after neoadjuvant therapy in rectal cancer with histopathologic comparison

BackgroundAfter neoadjuvant therapy, most of the lymph nodes (LNs) will shrink and disappear in patients with rectal cancer. However, LNs that are still detectable on MRI carry a risk of metastasis. This study aimed to evaluate the performance of the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) criterion (short-axis diameter ≥ 5 mm) in diagnosing malignant LNs in patients with rectal cancer after neoadjuvant therapy, and whether nodal morphological characteristics (including shape, border, signal homogeneity, and enhancement homogeneity) could improve the diagnostic efficiency for LNs ≥ 5 mm.MethodsThis retrospective study included 90 patients with locally advanced rectal cancer who underwent surgery after neoadjuvant therapy and performed preoperative MRI. Two radiologists independently measured the short-axis diameter of LNs and evaluated the morphological characteristics of LNs ≥ 5 mm in consensus. With a per node comparison with histopathology as the reference standard, a ROC curve was performed to evaluate the diagnostic performance of the size criterion. For categorical variables, either a χ2 test or Fisher’s exact test was used.ResultsA total of 298 LNs were evaluated. The AUC for nodal size in determining nodal status was 0.81. With a size cutoff value of 5 mm, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 65.9%, 87.0%, 46.8%, 93.6% and 83.9%, respectively. No significant differences were observed in any of the morphological characteristics between benign and malignant LNs ≥ 5 mm (all P > 0.05).ConclusionsThe ESGAR criterion demonstrated moderate diagnostic performance in identifying malignant LNs in patients with rectal cancer after neoadjuvant therapy. It was effective in determining the status of LNs < 5 mm but not for LNs ≥ 5 mm, and the diagnostic efficiency could not be improved by considering nodal morphological characteristics.

Biliary Anatomy 2.0 Quiz: Test Your Knowledge

Anatomy has remained an interest of physicians throughout the ages. The biliary tract spans from the liver to the hepatoduodenal mesentery, pancreas, and into the duodenum. Therefore, it is important for not only hepatobiliary surgeons but also general gastrointestinal surgeons, gastroenterologists, radiologists, and pathologists to be familiar with biliary anatomy and its variants. While surgery for hilar cholangiocarcinoma is one of the most challenging procedures, cholecystectomy is one of the most common procedures done from the beginning of surgical training. We hope that by answering the following questions, you will gain a comprehensive understanding of biliary anatomy and a greater appreciation for it.