Intestinal MRI in Inflammatory Bowel Disease - Literature and Survey-Based Recommendations regarding Reporting by the German Radiological Society (DRG) and the German Competence Network for Inflammatory Bowel Diseases

BACKGROUND

MR-enterography/enteroclysis (MRE) is increasingly used for primary diagnosis, detection of complications, and monitoring of patients with inflammatory bowel disease (IBD). Standardization of reporting is relevant to ensure quality of the methodology and to improve communication between different faculties. The current manuscript describes the features that are required for optimized reporting of MRE in IBD.

METHODS

An expert consensus panel of radiologists and gastroenterologists conducted a systematic search of the literature. In a Delphi process, members of the German Radiological Society (DRG) and members of the Competence Network for Inflammatory Bowel Diseases voted on relevant criteria for the reporting of findings in MRE. Based on the voting results, statements were developed by the expert consensus panel.

RESULTS

Clinically relevant aspects of MRE findings have been defined to optimize reporting and to standardize terminology. Minimal requirements for standardized reporting are suggested. The statements focus on the description of disease activity as well as on complications of IBD. Attributes of intestinal inflammation are described and illustrated by exemplary images.

CONCLUSION

The current manuscript provides standardized parameters and gives practical recommendations on how to report and how to characterize MRE findings in patients with IBD.

KEY POINTS

· Systematic overview provides practice-oriented recommendations and names and evaluates the decisive criteria for reporting and interpretation of MRI in inflammatory bowel disease.. · Standardized terminology and reporting criteria for MRI in IBD improves interdisciplinary communication.. · Standardized collection and documentation of MRI findings in IBD helps to further establish the method and to improve care for IBD patients..

CITATION FORMAT

· Wessling J, Kucharzik T, Bettenworth D et al. Intestinal MRI in Inflammatory Bowel Disease - Literature and Survey-Based Recommendations regarding Reporting by the German Radiological Society (DRG) and the German Competence Network for Inflammatory Bowel Diseases. Fortschr Röntgenstr 2023; 195: 675 - 690.

A Practical Index to Distinguish Backwash Ileitis From Crohn's Terminal Ileitis in MR Enterography

BACKGROUND

Differentiating ulcerative colitis-associated "backwash" ileitis (BWI) from Crohn's terminal ileitis (CTI) is a diagnostic challenge and highly affects patient's management. This study aimed to investigate magnetic resonance enterography (MRE) features including ileocecal valve patency index (ICPI) in patients with BWI and CTI and distinguish these entities based on MRE findings.

METHODS

After obtaining institutional review board approval, we reviewed 1654 MREs; 60 patients with pathologically proven BWI (n = 30) and CTI (n = 30) were enrolled. Two radiologists who were blinded to the clinical diagnosis analyzed MREs. We evaluated bowel wall thickness and enhancement pattern, ileocecal valve (ICV) diameter, and lip thickness. Ileocecal valve patency index-T and ICPI-C were calculated to normalize the ICV diameter with respect to terminal ileum (TI) and cecum, respectively. An additional group of non-BWI-UC patients (n = 30) was also included to validate indices.

RESULTS

Circumferential mural thickening (90% vs 1%, P < .001) and inner-wall enhancement (P < .001) of TI were more frequent in BWI patients than CTI. Serosal irregularity (53% vs 13%, P = .002), higher mural thickness (5mm vs 3mm, P < .001), and asymmetric hyperenhancement (P < .001) of TI were more prevalent in CTI than BWI. Ileocecal valve patency and lip atrophy were significantly higher in BWI than CTI and non-BWI-UC groups (both P < .001). Ileocecal valve patency indices-C and ICPI-T indices were able to accurately distinguish BWI from CTI (area under the ROC curve [AUC], 0.864 and 0.847 for ICPI-T and ICPI-C, respectively) and non-BWI-UC (AUC, 0.777 and 0.791 for ICPI-T and ICPI-C, respectively). Ileocecal valve patency indices-T  ≥31.5% were 100% specific to distinguish BWI from CTI, but sensitivity was 63%.

CONCLUSIONS

Magnetic resonance enterography features of ICV and TI can accurately differentiate BWI from CTI. Two practical indices introduced in this study showed high specificity to distinguish BWI from CTI.

Nodular lymphoid hyperplasia of terminal ileum: how to avoid overdiagnosis of Crohn's terminal ileitis in MR enterography?

PURPOSE

To investigate the magnetic resonance enterography (MRE) characteristics of nodular lymphoid hyperplasia (NLH) and Crohn's terminal ileitis (CTI).

METHODS

Of 1552 MREs from November 2011 to July 2018, 61 individuals with biopsy-proven NLH (n = 24) and CTI (n = 37, 27 with active CTI) were selected based on the inclusion criteria. NLH cases were also followed up for median (range) of 40 (21-61) months. Two board-certified radiologists, blind to clinical data and diagnosis, reviewed MRE in consensus. Conventional, morphological, enhancement, and diffusion parameters were assessed. Mann-Whitney, χ2, and logistic regression analyses were conducted.

RESULTS

No NLH patient developed inflammatory bowel disease or lymphoproliferative disorders during the follow-up. Serosal surface irregularity (65% vs. 8%), pseudo-diverticula (27% vs. 0), and mesenteric fat involvement (38% vs. 4%) were more frequent in CTI than NLH (p < 0.01), while mucosal nodularity was more prevalent in NLH (71%) than CTI (19%) (p < 0.001). The upstream luminal diameter (15.0 vs. 12.5 mm, p = 0.015) and mural thickness (6.0 vs. 4.0 mm, p < 0.001) of the terminal ileum showed higher values in CTI than NLH.

CONCLUSIONS

Unlike enhancement and diffusion parameters, morphological features (mucosal nodularity, serosal surface irregularity, and mesenteric fat involvement) could distinguish NLH from CTI regardless of CTI activity.

Magnetic resonance enterography compared with ultrasonography in newly diagnosed and relapsing Crohn's disease patients: the METRIC diagnostic accuracy study

BACKGROUND

Magnetic resonance enterography and enteric ultrasonography are used to image Crohn's disease patients. Their diagnostic accuracy for presence, extent and activity of enteric Crohn's disease was compared.

OBJECTIVE

To compare diagnostic accuracy, observer variability, acceptability, diagnostic impact and cost-effectiveness of magnetic resonance enterography and ultrasonography in newly diagnosed or relapsing Crohn's disease.

DESIGN

Prospective multicentre cohort study.

SETTING

Eight NHS hospitals.

PARTICIPANTS

Consecutive participants aged ≥ 16 years, newly diagnosed with Crohn's disease or with established Crohn's disease and suspected relapse.

INTERVENTIONS

Magnetic resonance enterography and ultrasonography.

MAIN OUTCOME MEASURES

The primary outcome was per-participant sensitivity difference between magnetic resonance enterography and ultrasonography for small bowel Crohn's disease extent. Secondary outcomes included sensitivity and specificity for small bowel Crohn's disease and colonic Crohn's disease extent, and sensitivity and specificity for small bowel Crohn's disease and colonic Crohn's disease presence; identification of active disease; interobserver variation; participant acceptability; diagnostic impact; and cost-effectiveness.

RESULTS

Out of the 518 participants assessed, 335 entered the trial, with 51 excluded, giving a final cohort of 284 (133 and 151 in new diagnosis and suspected relapse cohorts, respectively). Across the whole cohort, for small bowel Crohn's disease extent, magnetic resonance enterography sensitivity [80%, 95% confidence interval (CI) 72% to 86%] was significantly greater than ultrasonography sensitivity (70%, 95% CI 62% to 78%), with a 10% difference (95% CI 1% to 18%; p = 0.027). For small bowel Crohn's disease extent, magnetic resonance enterography specificity (95%, 95% CI 85% to 98%) was significantly greater than ultrasonography specificity (81%, 95% CI 64% to 91%), with a 14% difference (95% CI 1% to 27%). For small bowel Crohn's disease presence, magnetic resonance enterography sensitivity (97%, 95% CI 91% to 99%) was significantly greater than ultrasonography sensitivity (92%, 95% CI 84% to 96%), with a 5% difference (95% CI 1% to 9%). For small bowel Crohn's disease presence, magnetic resonance enterography specificity was 96% (95% CI 86% to 99%) and ultrasonography specificity was 84% (95% CI 65% to 94%), with a 12% difference (95% CI 0% to 25%). Test sensitivities for small bowel Crohn's disease presence and extent were similar in the two cohorts. For colonic Crohn's disease presence in newly diagnosed participants, ultrasonography sensitivity (67%, 95% CI 49% to 81%) was significantly greater than magnetic resonance enterography sensitivity (47%, 95% CI 31% to 64%), with a 20% difference (95% CI 1% to 39%). For active small bowel Crohn's disease, magnetic resonance enterography sensitivity (96%, 95% CI 92% to 99%) was significantly greater than ultrasonography sensitivity (90%, 95% CI 82% to 95%), with a 6% difference (95% CI 2% to 11%). There was some disagreement between readers for both tests. A total of 88% of participants rated magnetic resonance enterography as very or fairly acceptable, which is significantly lower than the percentage (99%) of participants who did so for ultrasonography. Therapeutic decisions based on magnetic resonance enterography alone and ultrasonography alone agreed with the final decision in 122 out of 158 (77%) cases and 124 out of 158 (78%) cases, respectively. There were no differences in costs or quality-adjusted life-years between tests.

LIMITATIONS

Magnetic resonance enterography and ultrasonography scans were interpreted by practitioners blinded to clinical data (but not participant cohort), which does not reflect use in clinical practice.

CONCLUSIONS

Magnetic resonance enterography has higher accuracy for detecting the presence, extent and activity of small bowel Crohn's disease than ultrasonography does. Both tests have variable interobserver agreement and are broadly acceptable to participants, although ultrasonography produces less participant burden. Diagnostic impact and cost-effectiveness are similar. Recommendations for future work include investigation of the comparative utility of magnetic resonance enterography and ultrasonography for treatment response assessment and investigation of non-specific abdominal symptoms to confirm or refute Crohn's disease.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN03982913.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 42. See the NIHR Journals Library website for further project information.

Differentiation of Colonic Inflammatory Bowel Disease: Re-examination of Paediatric Inflammatory Bowel Disease Classes Algorithm With Resected Colon As the Criterion Standard

OBJECTIVES

Differentiation of Crohn disease (CD) from ulcerative colitis (UC) is challenging when inflammation is predominantly colonic. The paediatric inflammatory bowel disease (PIBD) classes algorithm was developed to bring consistency to labelling, but used physician-assigned diagnosis as the criterion standard. We aimed to reassess the PIBD classes using pathology of subsequently resected colon as the criterion standard.

METHOD

Single-centre study of patients diagnosed with colonic IBD between 2002 and 2017 and subsequently treated with colectomy. Baseline pretreatment data were reviewed and the PIBD classes algorithm was independently applied by 2 reviewers to assign a label of UC/IBD-unclassified (IBD-U)/colonic-CD. Concordance between the algorithm-based, precolectomy clinical, and pathologic examination of resected colon diagnosis were assessed. Changes in diagnosis during postcolectomy follow-up were recorded.

RESULTS

Sixty-two children underwent colectomy for medically refractory colonic IBD. Diagnosis based on pathologic review of resected colon CD:4;UC:56;IBDU:2. The clinical, PIBD classes algorithm, and colectomy diagnoses were concordant in 51 of 62 patients (81%, Fleiss kappa 0.48). Precolectomy clinical diagnosis was concordant with colectomy diagnosis in 58 of 62 patients (94%, weighted-kappa 0.65). The PIBD classes label was concordant with colectomy diagnosis in 51 of 62 patients (82%, weighted-kappa 0.38); resected colon pathology was typical of UC in 6 patients with PIBD classes label of IBD-U based on single class 2 feature and in 3 with PIBD classes label of CD based on single class 1 feature.

CONCLUSIONS

Concordance of PIBD classes algorithm diagnosis applied before colectomy with a diagnostic label based on pathologic examination of a subsequently resected colon is only fair. Caution is needed in stringent application of colonic CD and IBD-U labels based on presence of single feature.

A Systematic Review of Technical Parameters for MR of the Small Bowel in non-IBD Conditions over the Last Ten Years

Technical guidelines for magnetic resonance imaging (MRI) of the small bowel (SB) in the setting of inflammatory bowel diseases (IBDs) were detailed in a 2017 consensus issued by European Society of Gastrointestinal and Abdominal Radiology (ESGAR) and European Society of Pediatric Radiology (ESPR); however, MRI for non-IBD conditions was not addressed. Hence, we performed a systematic review collecting researches on SB MRI for non-IBDs. The literatures were then divided into morphologic group and functional group. Information about the MRI techniques, gastrointestinal preparation, and details of cine-MRI protocols was extracted. We found that a 1.5 T MRI system, prone positioning, and MR enterography were frequently utilized in clinical practice. Gadolinium contrast sequences were routinely implemented, while diffusion-weighted imaging (DWI) was much less performed. The gastrointestinal preparation varied throughout the studies. No uniform protocols for cine imaging could be established. SB MRI examinations for non-IBDs are far from standardized, especially for functional studies. Recommendations for standard parameters in cine-MRI sequences are difficult to make due to lack of evidentiary support. MRI investigations in non-IBD conditions are needed and the standardization of non-IBD imaging in clinical practice is required.

Primary Immunodeficiency and the Gut

This article presents the most common gastrointestinal, hepatic, and pancreatic manifestations of the primary immunodeficiency diseases, including the appropriate laboratory testing, endoscopic evaluation, and recommendations for further management.

Assessment of normal jejunum with diffusion-weighted imaging on MRE in children

BACKGROUND

Diffusion restriction has been utilized as a marker for bowel inflammation on magnetic resonance enterography (MRE). However, diffusion restriction has been seen in otherwise normal appearing small bowel in patients without active inflammation, with little published data on this subject.

OBJECTIVE

Assess diffusion restriction in normal loops of jejunum and to determine if there is a correlation to luminal distention, age, magnet field strength, slice thickness, and bowel segment location.

MATERIALS AND METHODS

A retrospective analysis of subjects with a normal MRE and clinical work-up was performed. The abdomen was divided into four quadrants. If available, two loops of jejunum were randomly chosen in each quadrant. Two radiologists evaluated the loops of jejunum for distension, wall thickness, enhancement and diffusion restriction. Disagreement was resolved by consensus. Presence of diffusion restriction was correlated with luminal distension, age, magnet field strength, slice thickness and abdominal quadrant.

RESULTS

One hundred ninety-seven loops of jejunum were evaluated in 39 subjects. Fifteen subjects (38.5%) had jejunal loops with diffusion restriction for a total of 28 loops. There was no correlation between diffusion restriction and luminal distension, age, magnet field strength or quadrant location (P>0.05, Pearson chi-squared test or Student's t-tests). Of the 15 subjects with a loop demonstrating diffusion restriction, additional loops with diffusion restriction were found in 40%. There was a very weak trend observed for greater slice thickness in patients with jejunal diffusion restriction (Student's t-test, P=0.10).

CONCLUSION

Jejunal diffusion restriction is a common finding in children with no clinical evidence of bowel pathology, irrespective of patient age, luminal distension, location of bowel loop and magnetic field strength. Further studies may be valuable in assessing the impact of slice thickness on subjective diffusion restriction in the jejunum.

Paediatric magnetic resonance enterography in inflammatory bowel disease

Paediatric magnetic resonance enterography (MRE) has been increasingly employed in the evaluation of inflammatory bowel disease (IBD) in the past decade. This is in parallel with a global rise in paediatric-onset IBD, greater recognition of the hazards of ionizing radiation, especially in children, and improved treatment options. MRE is now the reference standard for assessing the small bowel in suspected or proven paediatric IBD, and is central to the diagnosis of Crohn's disease (CD), helping distinguish it from ulcerative colitis. This review will discuss the standard and advanced techniques applied in paediatric MRE to define the presence, extent and severity of intestinal IBD, and increasingly colonic and perianal disease. Its role in demonstrating enteric and extra-enteric disease and characterizing this as active inflammation and/or damage will be explored, including the utility of cinematic, diffusion weighted and magnetization transfer imaging. While MRE is increasingly used to guide medical versus surgical management, considerable overlap exists between conventional MRE imaging features for inflammation and damage, as reflected pathologically, which is driving ongoing research. Paediatric MRE-based scoring systems for CD are currently under development that will further consolidate the role of MRE in paediatric IBD, reinforced by implementation of standardized analysis, interpretation and reporting. As an imaging biomarker, MRE performs well when referenced against endoscopy and clinical biomarkers for evidence of mucosal healing, the current treatment goal. MRE is anticipated to have even greater impact as an imaging biomarker through demonstration of transmural disease and healing, not amenable to endoscopic assessment.

Consensus Recommendations for Evaluation, Interpretation, and Utilization of Computed Tomography and Magnetic Resonance Enterography in Patients With Small Bowel Crohn's Disease

Computed tomography and magnetic resonance enterography have become routine small bowel imaging tests to evaluate patients with established or suspected Crohn's disease, but the interpretation and use of these imaging modalities can vary widely. A shared understanding of imaging findings, nomenclature, and utilization will improve the utility of these imaging techniques to guide treatment options, as well as assess for treatment response and complications. Representatives from the Society of Abdominal Radiology Crohn's Disease-Focused Panel, the Society of Pediatric Radiology, the American Gastroenterological Association, and other experts, systematically evaluated evidence for imaging findings associated with small bowel Crohn's disease enteric inflammation and established recommendations for the evaluation, interpretation, and use of computed tomography and magnetic resonance enterography in small bowel Crohn's disease. This work makes recommendations for imaging findings that indicate small bowel Crohn's disease, how inflammatory small bowel Crohn's disease and its complications should be described, elucidates potential extra-enteric findings that may be seen at imaging, and recommends that cross-sectional enterography should be performed at diagnosis of Crohn's disease and considered for small bowel Crohn's disease monitoring paradigms. A useful morphologic construct describing how imaging findings evolve with disease progression and response is described, and standard impressions for radiologic reports that convey meaningful information to gastroenterologists and surgeons are presented.

Consensus Recommendations for Evaluation, Interpretation, and Utilization of Computed Tomography and Magnetic Resonance Enterography in Patients With Small Bowel Crohn's Disease

Computed tomography and magnetic resonance enterography have become routine small bowel imaging tests to evaluate patients with established or suspected Crohn's disease, but the interpretation and use of these imaging modalities can vary widely. A shared understanding of imaging findings, nomenclature, and utilization will improve the utility of these imaging techniques to guide treatment options, as well as assess for treatment response and complications. Representatives from the Society of Abdominal Radiology Crohn's Disease-Focused Panel, the Society of Pediatric Radiology, the American Gastroenterological Association, and other experts, systematically evaluated evidence for imaging findings associated with small bowel Crohn's disease enteric inflammation and established recommendations for the evaluation, interpretation, and use of computed tomography and magnetic resonance enterography in small bowel Crohn's disease. This work makes recommendations for imaging findings that indicate small bowel Crohn's disease, how inflammatory small bowel Crohn's disease and its complications should be described, elucidates potential extra-enteric findings that may be seen at imaging, and recommends that cross-sectional enterography should be performed at diagnosis of Crohn's disease and considered for small bowel Crohn's disease monitoring paradigms. A useful morphologic construct describing how imaging findings evolve with disease progression and response is described, and standard impressions for radiologic reports that convey meaningful information to gastroenterologists and surgeons are presented. ^©2018, RSNA, AGA Institute, and Society of Abdominal Radiology This article is being published jointly in Radiology and Gastroenterology.

Crohn's disease diagnosis, treatment approach, and management paradigm: what the radiologist needs to know

Crohn's disease is one of the major subtypes of idiopathic inflammatory bowel disease and is characterized by chronic transmural intestinal inflammation of the gastrointestinal tract anywhere from mouth to the anus, with a predilection for the small bowel. Cross-sectional imaging with computed tomography and magnetic resonance enterography plays a key role in confirming diagnosis, identifying and managing complications, assessing disease severity, and identifying response to medical therapy. This review will focus on the role of radiologists in the diagnosis and assessment of Crohn's disease. Additionally, a review of current medical therapy approaches, available medications, and side effects will be discussed. The review will also highlight key complications of medical therapy and associated diseases that should be evaluated by the radiologist with cross-sectional imaging.

Diffusion-weighted MR enterography for evaluating Crohn's disease: Effect of anti-peristaltic agent on the diagnosis of bowel inflammation

OBJECTIVES

To prospectively investigate how Buscopan affects the diagnosis of bowel inflammation by diffusion-weighted imaging MR enterography (DWI-MRE) in Crohn's disease (CD).

METHODS

Thirty CD patients without previous bowel surgery underwent DWI-MRE (b = 900 sec/mm²) before and after intravenous Buscopan. The 30 patients were randomly divided into two groups; using a crossover design, interpretations were made regarding the presence of restricted mural diffusion (i.e., bowel inflammation) in nine bowel segments in two separate reading sessions by two readers. The readers also judged restricted mural diffusion extent in each bowel segment on two side-by-side DWI-MRE images with a random right-to-left order. Ileocolonoscopy and conventional MRE interpreted by an expert panel were reference standards.

RESULTS

We analyzed 262 bowel segments. DWI-MRE without Buscopan significantly decreased sensitivity for both readers (58.8 % vs. 72.9 %, P = 0.046; 57.6 % vs. 85.9 %, P = 0.001) and did not significantly increase specificity (P = 0.085 and 0.396). Two readers noted that 28.6 % and 23.3 % of 262 bowel segments had greater diffusion restriction extent on DWI-MRE with Buscopan compared with DWI-MRE without Buscopan (P < 0.001) and 68.7 % and 74 %, respectively, had similar extent between them.

CONCLUSION

Omitting Buscopan caused a greater loss in sensitivity of DWI-MRE than false-positive reduction for diagnosing bowel inflammation in CD.

KEY POINTS

• Omitting Buscopan significantly decreases DWI-MRE sensitivity for diagnosing bowel inflammation in CD. • Increase in the corresponding DWI-MRE specificity by omitting Buscopan is less apparent. • DWI-MRE without Buscopan underestimates the extent of bowel inflammation in CD.

DWI at MR Enterography for Evaluating Bowel Inflammation in Crohn Disease

OBJECTIVE

The purpose of this article is to provide a comprehensive review regarding DWI enterography used for evaluating Crohn disease and to summarize the relevant evidence.

CONCLUSION

Active bowel inflammation in Crohn disease causes restricted diffusion on MR enterography with DWI. Enterographic DWI to evaluate Crohn disease is increasingly drawing attention for both academic research and clinical practice and has shown potential as a quantitative tool for assessing bowel inflammation. DWI enterography also has multiple unresolved issues and limitations.

Capsule Endoscopy for Ileitis with Potential Involvement of Other Sections of the Small Bowel

Ileitis is defined as inflammation of the ileum. This condition includes ulcers, aphthous ulcers, erosions, and nodular or erythematous mucosa. Various etiologies are associated with ileitis. Crohn's disease, ulcerative colitis, medications such as nonsteroidal anti-inflammatory drugs, infectious conditions, neoplasms, infiltrative disorders, vasculitides, spondyloarthritis, endometriosis, and radiation therapy-related conditions involve the ileum. However, the differential diagnosis of terminal ileitis can be difficult in many cases. Video capsule endoscopy (VCE) has become a useful tool for the diagnosis of a variety of small bowel lesions. This review describes each of the various conditions associated with ileitis and the diagnostic value of VCE for ileitis, which may help identify and evaluate these conditions in clinical practice. Based on the information provided by VCE, a definitive diagnosis could be made using the patients' medical history, clinical course, laboratory and ileocolonoscopic findings, radiologic imaging findings, and histologic findings.