Comparison of CT enterography and MR enterography imaging features of active Crohn disease in children and adolescents

Multimodality Imaging of Small Bowel Crohn Disease

Computed tomography enterography, magnetic resonance enterography, and bowel ultrasound are complementary tools central to diagnosing and monitoring Crohn disease. These modalities can identify active inflammation, penetrating, and stricturing disease. Crohn disease must be monitored frequently to guide therapy, and resolution of inflammation on imaging correlates directly with steroid-free clinical remission. While disease activity assessment is qualitative, newer quantitative techniques to assess active inflammation are emerging. These as well as other techniques, such as contrast-enhanced ultrasound (US) and US elastography, will offer new tools for future radiologists.

Different imaging techniques' diagnostic efficacy for Crohn's disease activity and external validation and comparison of MDCTAs, SES-CD and IBUSSAS

BACKGROUND

Crohn's disease (CD) is a chronic inflammatory disease of the digestive tract with unknown etiology. It follows a relapse-remission pattern, making disease activity assessment crucial for treatment. Our study aims to evaluate the diagnostic accuracy of various imaging modalities and to validate and compare the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS), the multidetector computed tomography enterography score (MDCTEs), and the simplified endoscopic activity score for Crohn's disease (SES-CD).

METHODS

We assessed diagnostic performance using the CD Activity Index (CDAI). We first categorized patients into remission and active groups. For those in the active stage, we further categorized them into mild/moderate and severe activity groups. We used Spearman rank correlation to evaluate the relationships among IBUS-SAS, bowel wall thickness (BWT), Color Doppler imaging signal (CDS), inflammatory fat (i-fat), bowel wall stratification (BWS), and clinical inflammatory indicators.

RESULTS

A total of 103 CD patients were evaluated. The IBUS-SAS cut-off for remission and activity was 23.8, with an AUC of 0.923, sensitivity of 91.4%, and specificity of 84.8%. The SES-CD had an AUC of 0.801, sensitivity of 62.9%, and specificity of 84.4% at a cut-off of 4.5. The MDCTEs showed an AUC of 0.855, sensitivity of 77.1%, and specificity of 75.8% for a cut-off of 6.5. The Delong test revealed significant differences in diagnostic efficacy when comparing IBUS-SAS to SES-CD and IBUS-SAS to MDCTEs. In the group of mild or moderate-to-severe active, the IBUS-SAS had an AUC of 0.925, sensitivity of 83.7%, and specificity of 88.9% at a cut-off of 40. The SES-CD exhibited an AUC of 0.850, sensitivity of 90.7%, and specificity of 70.4% at a cut-off of 8.5. MDCTEs showed an AUC of 0.909, sensitivity of 83.7%, and specificity of 85.2% at a cut-off of 8.5. During Delong test, the IBUS-SAS, MDCTEs, and SES-CD showed no significant differences in assessing moderate-to-severe activity. Both IBUS-SAS and ultrasound parameters correlated with certain serum indicators (p < 0.05), although only weakly to moderately (all r < 0.5).

CONCLUSION

The IBUS-SAS, MDCTEs and SES-CD can evaluate disease remission/active and mild/moderate-to-severe active in CD, and IBUS-SAS offers the potential to precisely define CD activity.

Imaging of Gastrointestinal Tract Ailments

Gastrointestinal (GI) disorders comprise a diverse range of conditions that can significantly reduce the quality of life and can even be life-threatening in serious cases. The development of accurate and rapid detection approaches is of essential importance for early diagnosis and timely management of GI diseases. This review mainly focuses on the imaging of several representative gastrointestinal ailments, such as inflammatory bowel disease, tumors, appendicitis, Meckel's diverticulum, and others. Various imaging modalities commonly used for the gastrointestinal tract, including magnetic resonance imaging (MRI), positron emission tomography (PET) and single photon emission computed tomography (SPECT), and photoacoustic tomography (PAT) and multimodal imaging with mode overlap are summarized. These achievements in single and multimodal imaging provide useful guidance for improved diagnosis, staging, and treatment of the corresponding gastrointestinal diseases. The review evaluates the strengths and weaknesses of different imaging techniques and summarizes the development of imaging techniques used for diagnosing gastrointestinal ailments.

[68Ga]Ga-FAPI-04 PET/CT on assessing Crohn's disease intestinal lesions

BACKGROUND

Fibrosis and inflammation are major pathological changes of Crohn's disease (CD). Early detection and accurate severity evaluation of CD are critical for patient's prognosis. Endoscopy is widely used to evaluate CD progression. Herein, we evaluated the efficacy of [⁶⁸Ga]Ga-FAPI-04 PET/CT to identify lesions and assess the progression of CD.

METHODS

All CD patients received computed tomography enterography (CTE), [⁶⁸Ga]Ga-FAPI-04 PET/CT examination, and ileocolonoscopy within 1 week. Two independent gastroenterologists computed the Crohn's disease activity index (CDAI) of all patients. Two radiology physicians assessed the CTE images separately, and the CTE scores were calculated. Lastly, two nuclear medicine physicians independently examined the [⁶⁸Ga]Ga-FAPI-04 PET/CT images. Once the FAPI uptake of the intestinal segment was equal or higher relative to the liver (considered FAPI-positive), the target-to-background ratio (TBR) and global FAPI PET/CT score were computed, representing the independent intestinal activity and activity of all intestinal segments, respectively. Levels of fecal calprotectin (FCP) and C-reactive protein (CRP) were determined before the endoscopy. The Crohn's disease endoscopy index of severity (CDEIS) and the simple endoscopic score for Crohn's disease (SES-CD) were calculated during the endoscopy. Finally, all data were obtained and analyzed.

RESULTS

There were 74 intestinal segments in 16 patients were assessed. [⁶⁸Ga]Ga-FAPI-04 PET/CT identified 42 of 45 endoscopically lesioned segments (endoscopic lesions detection sensitivity: 93.3%), while CTE identified 39 of them (endoscopic lesions detection sensitivity: 86.7%). According to the receiver operating characteristic (ROC) analysis, [⁶⁸Ga]Ga-FAPI-04 PET/CT showed better performance in the detection of endoscopic lesions compared with CTE (P < 0.05). The TBR was significantly associated with the CTE score (r = 0.81; (95% CI): 0.736-0.869; P < 0.0001) and SES-CD values (r = 0.86; (95% CI): 0.776-0.908; P < 0.0001). In addition, the global FAPI PET/CT score was significantly correlated with FCP (r = 0.52; 95% CI, 0.02-0.81; P = 0.039), CRP (r = 0.60; 95% CI, 0.13-0.85; P = 0.014), CDEIS (r = 0.55; 95% CI, 0.06-0.83; P = 0.028), and CDAI (r = 0.81; 95% CI, 0.50-0.93; P < 0.0001).

CONCLUSION

In summary, [⁶⁸Ga]Ga-FAPI-04 PET/CT correlated well with endoscopic, CTE, clinical, and biomarkers of CD. It was also highly sensitive in the detection of different classes of lesions in all intestinal segments, and unlike other examinations, this technique required no patient fasting or bowel preparation. Therefore, [⁶⁸Ga]Ga-FAPI-04 PET/CT may be a promising method for assessing the activity of CD.

Initial Abdominal CT and Laboratory Findings Prior to Diagnosis of Crohn's Disease in Children

PURPOSE

To identify initial abdominal computed tomography (CT) and laboratory findings prior to a diagnosis of Crohn's disease (CD) in children.

MATERIALS AND METHODS

In this retrospective study, patients (≤18 year-old) who were diagnosed with CD from 2004 to 2019 and had abdominal CT just prior to being diagnosed with CD were included in the CD group. Patients (≤18 years old) who were diagnosed with infectious enterocolitis from 2018 to 2019 and had undergone CT prior to being diagnosed with enterocolitis were included as a control group. We assessed the diagnostic performances of initial CT and laboratory findings for the diagnosis of CD using logistic regression and the area under the curve (AUC).

RESULTS

In total, 107 patients (50 CD patients, 57 control patients) were included, without an age difference between groups (median 13 years old vs. 11 years old, p=0.119). On univariate logistic regression analysis, multisegmental bowel involvement, mesenteric vessel engorgement, higher portal vein/aorta diameter ratio, longer liver longitudinal diameter, lower hemoglobin (≤12.5 g/dL), lower albumin (≤4 g/dL), and higher platelet (>320×10³/µL) levels were significant factors for CD. On multivariate analysis, multisegmental bowel involvement [odds ratio (OR) 111.6, 95% confidence interval (CI) 4.778-2605.925] and lower albumin levels (OR 0.9, 95% CI 0.891-0.993) were significant factors. When these two features were combined, the AUC value was 0.985 with a sensitivity of 96% and specificity of 100% for differentiating CD.

CONCLUSION

Multisegmental bowel involvement on CT and decreased albumin levels can help differentiate CD from infectious enterocolitis in children prior to a definite diagnosis of CD.

ACR Appropriateness Criteria® Crohn Disease-Child

Crohn disease is an inflammatory condition of the gastrointestinal tract with episodes of exacerbation and remission occurring in children, adolescents, and adults. Crohn disease diagnosis and treatment depend upon a combination of clinical, laboratory, endoscopic, histological, and imaging findings. Appropriate use of imaging provides critical information in the settings of diagnosis, assessment of acute symptoms, disease surveillance, and therapy monitoring. Four variants are discussed. The first variant discusses the initial imaging for suspected Crohn disease before established diagnosis. The second variant pertains to appropriateness of imaging modalities during suspected acute exacerbation. The third variant is a substantial discussion of recommendations related to disease surveillance and monitoring of Crohn disease. Finally, panel recommendations and discussion of perianal fistulizing disease imaging completes the document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Radiology plus ileocolonoscopy versus radiology alone in Crohn's disease: prognosis prediction and mutual agreement

BACKGROUND/AIMS

The optimal tools for monitoring Crohn's disease (CD) are controversial. We compared radiology plus ileocolonoscopy and radiology alone in terms of prognosis prediction and evaluated the agreement between radiologic and ileocolonoscopic findings in patients with CD.

METHODS

Patients with CD who were followed up with computed tomography enterography (CTE) or magnetic resonance enterography (MRE) alone or CTE or MRE plus ileocolonoscopy were retrospectively recruited. Time to relapse was investigated to evaluate the difference in prognosis using the log-rank and Cox regression tests, and the agreement between radiologic and ileocolonoscopic findings was determined using a kappa value.

RESULTS

A total of 501 patients with CD in clinical remission who underwent CTE or MRE and/or ileocolonoscopy were analyzed. Of these, 372 (74.3%) patients underwent CTE or MRE alone and 129 (25.7%) patients underwent CTE or MRE plus ileocolonoscopy. The cumulative maintenance rate of clinical remission between the two groups was not significantly different (p = 0.526, log-rank test). In multivariate analysis, age <40 years (hazard ratio [HR], 2.756; 95% confidence interval [CI], 1.263 to 6.013) and a history of steroid use (HR, 2.212; 95% CI, 1.258 to 3.577) were found to independently predict an increased risk for clinical relapse in patients with CD in clinical remission. Radiologic and ileocolonoscopic findings had a moderate degree of agreement (κ = 0.401, -0.094 to 0.142). The comparison of agreement between radiologic and ileocolonoscopic findings was the highest in the anastomotic site (κ = 0.749, -0.168 to 0.377).

CONCLUSION

Radiology plus ileocolonoscopy was not superior to radiology alone in predicting the prognosis of CD.

Diagnostic accuracy of CT enterography correlated to histopathology in the diagnosis of small bowel Crohn's disease

BACKGROUND

Crohn's disease (CD) is a chronic inflammatory process affecting the gastrointestinal tract, mainly the terminal ileum of small bowel. Although ileocolonoscopy provides good mucosal visualization, it does not allow evaluation of extraluminal abnormalities. Computed tomographic enterography (CTE) is an emerging imaging modality for assessment of small bowel disorders. The study aimed to explore the diagnostic accuracy of CTE in the diagnosis of patients with CD benchmarked against a histopathological reference.

METHODS

A cross-sectional study entailed 126 consecutive patients with known or suspected CD who underwent CTE and biopsy by ileocolonoscopy via retrograde terminal ileum intubation. Spearman's rank was used to test the correlation and Kappa coefficient agreement between CTE and histopathology. Area under the curve (AUC) of receiver operating characteristic (ROC) was used to measure CTE diagnostic accuracy.

RESULTS

The overall sensitivity and specificity of CTE were 93.88% and 85.71%, respectively. The PPV was 95.83%, and the NPV was 80%. The accuracy of CTE indicated an overall probability of correct patient classification of 92.06%. The AUC of the ROC of CTE was 0.898 (P < 0.001). Thus, CTE has a high sensitivity for assessment of small bowel CD. The CTE and histopathological gradings were strongly correlated (Spearman's coefficient = 0.962, P < 0.001). CTE exhibited perfect agreement with histopathology (Kappa coefficient (κ) = 0.847, P < 0.001).

CONCLUSION

CTE is a reliable technique that has high diagnostic accuracy in the assessment of CD. Hence, it may be useful for follow up and for preoperative guidance in treatment planning.

CT Enterography Using Four Different Endoluminal Contrast Agents: A Comparative Study

Objectives To determine the most preferable endoluminal contrast agent among mannitol, polyethylene glycol (PEG), iohexol, and water by comparing various qualitative (distension, fold visibility, and homogeneity) and quantitative parameters (distension) along with artifacts and patient feedback for computed tomography enterography (CTE).

Methods This was a prospective study including 120 patients of age more than or equal to 18 years who were randomized equally into four groups. Group 1 was given 1500 mL of 3% mannitol solution, group 2 was given 1500 mL of PEG, group 3 was given 20 mL of iohexol dissolved in 1500 mL of water, and group 4 was given 1500 mL of plain water. CTE was done and images were evaluated in axial and coronal planes. Various quantitative and qualitative parameters were taken at the level of second part of duodenum, jejunum, ileum and ileocecal junction (ICJ). Artifacts and patient feedback were also taken into consideration.

Results The quantitative distension and grading, qualitative distension, fold visibility, and homogeneity of the second part of duodenum, jejunum at the level of superior mesenteric artery, inferior mesenteric artery and renal artery on both sides of abdomen, ileum at the level of aortic bifurcation, common iliac bifurcation, and deep pelvis on both sides of abdomen and ICJ were significantly more in PEG group as compared with mannitol group, followed by iohexol and water group. The results were calculated by ANOVA test using p-value. In terms of patient feedback and artifacts, water was the best agent.

Conclusions PEG is the most suitable contrast agent to carry out CTE. Distension, fold visibility, and homogeneity are the essential features for a better diagnostic outcome of CTE, which was better with PEG.

Implications of lymphatic alterations in the pathogenesis and treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is characterized by intense immune dysregulation, gut microbiota imbalance, and intestinal epithelium destruction. Among the factors that contribute to the pathogenesis of IBD, lymphatics have received less attention, hence less studied, characterized, and explored. However, in recent years, the role of the lymphatic system in gastrointestinal pathophysiology continues to be highlighted. This paper examines the implications of lymphatic changes in IBD pathogenesis related to immune cells, gut microbiota, intestinal and mesenteric epithelial barrier integrity, and progression to colorectal cancer (CRC). Therapeutic targets of lymphatics in IBD studies are also presented. Available studies indicate that lymph nodes and other secondary lymphatic tissues, provide highly specialized microenvironments for mounting effective immune responses and that lymphatic integrity plays a significant role in small intestine homeostasis, where the lymphatic vasculature effectively controls tissue edema, leukocyte exit, bacterial antigen, and inflammatory chemokine clearance. In IBD, there are functional and morphological alterations in intestinal and mesenteric lymphatic vessels (more profoundly in Crohn's disease [CD] compared to ulcerative colitis [UC]), including lymphangiogenesis, lymphangiectasia, lymphadenopathy, and lymphatic vasculature blockade, affecting not only immunity but gut microbiota and epithelial barrier integrity. While increased lymphangiogenesis is primarily associated with a good prognosis of IBD, increased lymphangiectasia, lymphadenopathy, and lymphatic vessel occlusion correlate with poor prognosis. IBD therapies that target the lymphatic system seek to increase lymphangiogenesis via induction of lymphangiogenic factors and inhibition of its antagonists. The resultant increased lymphatic flow coupled with other anti-inflammatory activities restores gut homeostasis.

Prospective comparison of diffusion-weighted magnetic resonance enterography and contrast enhanced computed tomography enterography for the detection of ileocolonic Crohn's disease

BACKGROUND AND AIMS

Crohn's disease (CD) is a chronic and relapsing course with various status of different segments, and there were no investigations comparing the lesion detection between magnetic resonance (MR) and computed tomography (CT) in term of the severity of CD. We aim to assess the performances of diffusion-weighted MR enterography (DW-MRE) and contrast enhanced CT enterography (CTE) for detecting different grade lesions in ileocolonic CD.

METHODS

Forty-one consecutive patients finally diagnosed with ileocolonic CD were included. All the patients prospectively underwent DW-MRE, contrast enhanced CTE, and ileocolonoscopy within 2 weeks. DW-MRE and CTE images were interpreted for the presence or absence of active CD segments by two experienced radiologists independently. Ileocolonic segments (terminal ileum, right colon, transverse colon, left colon, and rectum) were graded as inactive (0-2), mild (3-6), or moderate-severe (≥ 7) by the simplified endoscopic score for CD (SES-CD). Diagnostic efficiencies of DW-MRE and CTE for mild and/or moderate-severe CD segments were calculated and compared, using ileocolonoscopy as reference standard.

RESULTS

According to SES-CD, 190 ileocolonic segments from 41 CD patients were scored as 91 inactive, 68 mild, and 31 moderate-severe CD lesions. The sensitivity of DW-MRE for detecting active from inactive segments was higher than that of CTE, and the specificities of them had no significant differences. As for the subgroup analysis, DW-MRE was more sensitive for mild CD lesions than CTE (76.5% vs 60.3%; P = 0.019), while the sensitivities for moderate-severe CD were similar between these two modalities (96.8% for DW-MRE and 93.5% for CTE; P = 1.00).

CONCLUSIONS

Both DW-MRE and CTE had comparably excellent performances for moderate-severe CD detection; DW-MRE demonstrated better sensitivity in mild lesions compared with CTE and could be more suitable for the diagnosis of mild CD.

The feasibility of differentiating colorectal cancer from normal and inflammatory thickening colon wall using CT texture analysis

To investigate the diagnostic value of texture analysis (TA) for differentiating between colorectal cancer (CRC), colonic lesions caused by inflammatory bowel disease (IBD), and normal thickened colon wall (NTC) on computed tomography (CT) and assess which scanning phase has the highest differential diagnostic value. In all, 107 patients with CRC, 113 IBD patients with colonic lesions, and 96 participants with NTC were retrospectively enrolled. All subjects underwent multiphase CT examination, including pre-contrast phase (PCP), arterial phase (AP), and portal venous phase (PVP) scans. Based on these images, classification by TA and visual classification by radiologists were performed to discriminate among the three tissue types. The performance of TA and visual classification was compared. Precise TA classification results (error, 2.03–12.48%) were acquired by nonlinear discriminant analysis for CRC, IBD and NTC, regardless of phase or feature selection. PVP images showed a better ability to discriminate the three tissues by comprising the three scanning phases. TA showed significantly better performance in discriminating CRC, IBD and NTC than visual classification for residents, but there was no significant difference in classification between TA and experienced radiologists. TA could provide useful quantitative information for the differentiation of CRC, IBD and NTC on CT, particularly in PVP images.

[Preparation, Technique, and Imaging of Computed Tomography/Magnetic Resonance Enterography]

CT enterography and magnetic resonance (MR) enterography are widely used imaging modalities used to examine the small bowel. These radiologic tests are distinguished from routine abdominopelvic CT and MRI by the oral ingestion of a large amount of neutral contrast to distend the small bowel before scanning. For achievement of high quality, diagnostic images and proper technique are required. Conducted protocols still vary in patient preparation, enteric contrast, and CT and MRI acquisition sequences, resulting in heterogeneous diagnostic accuracy. The purpose of this article is to review the processes and techniques that optimize CT/MR enterography for patients with suspected Crohn's disease or other small bowel diseases.

Texture Analysis of Magnetic Resonance Enterography Contrast Enhancement Can Detect Fibrosis in Crohn Disease Strictures

OBJECTIVE

The aim of the study was to investigate if texture analysis of contrast-enhanced magnetic resonance enterography (MRE) images can determine Crohn disease (CD) stricture histologic type.

MATERIALS AND METHODS

A radiology report database query identified 25 pediatric patients with established CD who underwent MRE followed by bowel resection within 30 days. MRE images were reviewed to identify strictures on enteric phase T1-weighted fat-suppressed images, that were matched with sites of histologic sectioning. Regions of interest were drawn over the bowel wall and texture analysis was performed using TexRAD software (Cambridge, UK), with skewness, mean, entropy and standard deviation parameters assessed. A pathologist reviewed all stricture histology specimens to assess for active mucosal inflammation and mural fibrosis. Multivariate logistic regression and analysis of variance were performed to identify texture features associated with stricture fibrosis.

RESULTS

Sixty-four bowel segments from 25 patients (mean age 16 ± 2 years) with imaging-histologic correlation were included. Of note, all strictures included had undergone surgical resection with MRE imaging available within 30 days. The histologic distribution of these bowel segments included 9 segments that showed active inflammation without fibrosis, 23 segments that showed only fibrosis, and 32 mixed segments with concomitant active inflammation and fibrosis. Bivariate regression analysis demonstrated that skewness, standard deviation, entropy, and mean texture analysis features are independently associated with stricture fibrosis. Stepwise logistic regression showed that the combination of mean, skewness, and entropy texture predicted stricture fibrosis with a goodness-of-fit value of 0.995. A combination of threshold values for these 3 texture analysis parameters was able to correctly classify 100% of the strictures in the study cohort for presence (55/55) and absence (9/9) of fibrosis.

CONCLUSIONS

MRE texture analysis (MRE-TA) texture features can differentiate CD stricture types and accurately detect fibrosis.

Inter-radiologist agreement using Society of Abdominal Radiology-American Gastroenterological Association (SAR-AGA) consensus nomenclature for reporting CT and MR enterography in children and young adults with small bowel Crohn disease

PURPOSE

To assess inter-radiologist agreement using the Society of Abdominal Radiology-American Gastroenterological Association (SAR-AGA) consensus recommendations for reporting CT/MR enterography exams in pediatric and young adult small bowel Crohn disease (CD).

METHODS

Institutional review board approval was obtained for this HIPAA-compliant retrospective investigation; the requirement for informed consent was waived. 25 CT and 25 MR enterography exams performed in children and young adults (age range: 6-23 years) between January 2015 and April 2017 with a distribution of ileal CD severity (phenotype) were identified: normal or chronic CD without active inflammation (40%), active inflammatory CD (20%), stricturing CD (20%), and penetrating CD (20%). Five fellowship-trained pediatric radiologists, blinded to one another, documented key imaging findings and standardized impressions based on SAR-AGA consensus recommendations. Inter-radiologist agreement was evaluated using Fleiss' multi-rater kappa statistic (κ) with 95% confidence intervals (CI).

RESULTS

Inter-radiologist agreement was moderate for all key imaging findings except presence of ulcerations (κ 0.37 [95% CI 0.28-0.46]) and sacculations (κ 0.31 [95% CI 0.23-0.40]). Agreement for standardized impressions was substantial for stricturing disease (κ 0.79 [95% CI 0.70-0.87]) and moderate for presence of inflammation (κ 0.49 [95% CI 0.44-0.56]) and penetrating disease (κ 0.58 [95% CI 0.49-0.67]). No significant difference in agreement was found between CT and MRI.

CONCLUSIONS

Agreement among five pediatric radiologists was moderate to substantial for SAR-AGA standardized impressions and fair to moderate for key imaging findings of pediatric and young adult CD.

The Mesentery, Systemic Inflammation, and Crohn's Disease

Initially thought to be a structure that only provided support to the abdominal contents, the mesentery has now gained special attention in the scientific community. The new approach of studying the mesentery as an individual organ has highlighted its importance in the development of local and systemic inflammatory diseases and its potential role in Crohn's disease. Its topographical relationship with the intestine in the setting of active inflammation and "creeping fat" is possibly one of the most important arguments for including the mesentery as an important factor in the pathogenesis of Crohn's disease. In this review, we discuss the importance of the mesentery from the anatomical and embryological standpoints. We also will summarize data on mesenteric inflammation in patients with Crohn's disease. The significance of the mesentery in systemic inflammatory syndromes will be discussed, and we provide an overview of primary inflammatory disorders of the mesentery. Finally, we discuss surgical approaches for patients requiring resection for Crohn's disease that incorporate mesenteric factors, pointing out recent data suggesting that these have the potential for improving outcomes and reducing disease recurrence. 10.1093/ibd/izy201_video1izy201.video15794169491001.

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.

Magnetic resonance enterography evaluation of Crohn disease activity and mucosal healing in young patients

MR enterography (MRE) has become the primary imaging modality for assessing Crohn disease in young patients because of its lack of ionizing radiation, superior soft-tissue contrast, and cross-sectional capability to evaluate disease activity as well as extraluminal and extra-intestinal complications. MRE has been extensively validated against both histological and endoscopic references as a noninvasive imaging biomarker of Crohn disease activity. More recent studies have also validated MRE as a noninvasive biomarker of mucosal healing, an important endpoint of Crohn disease therapy. In this review, we summarize the current evidence supporting the use of MRE features as imaging biomarkers of Crohn disease activity and treatment response.

Computed Tomography Enterography: Quantitative Evaluation on Crohn's Disease Activity

Objective

To explore the feasibility of computed tomography enterography (CTE) in the quantitative evaluation of the activity of Crohn's disease (CD).

Methods

There were 49 CD patients with whole clinical, enteroscopy, and CTE data to be analyzed retrospectively. The patients were graded as inactive (0–2), mild (3–6), and moderate-severe group (>6) based on simplified endoscopic activity score for Crohn's disease (SES-CD). The differences in bowel wall thickening, mural hyperenhancement in the portal vein period, and the ΔCT values were analyzed among groups using ANOVA (analysis of variance) and q test. Then, the parameters were correlated with SES-CD, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR).

Results

In the 49 patients, 13 ones were inactive, 19 ones were mild, and 17 ones were moderate-severe; the thickness of bowel wall, mural hyperenhancement in the portal vein period, and ΔCT value among groups were all significantly different (P < 0.001 in all). Correlative analysis showed that compared with the SES-CD, the bowel wall thickening (r = 0.564, P < 0.001), mural hyperenhancement in the portal vein period (r = 0.585, P < 0.001), and ΔCT value (r = 0.533, P < 0.001) were moderately correlated.

Conclusion

The mural hyperenhancement in the portal vein period, bowel wall thickening, and ΔCT value can accurately and quantitatively assess the activity of CD lesions and are potential visual biomarkers of CD lesions.

Effective communication of cross-sectional imaging findings in Crohn's disease: comparing conventional EMR reporting to a published scoring system

PURPOSE

The purpose of the article is to compare information regarding small bowel lesions in Crohn's disease (CD) patients communicated by a published scoring system and radiology reports from electronic medical record (EMR) of cross-sectional abdominal imaging.

METHODS

Two gastrointestinal radiologists (reference readers) blinded to EMR reports scored cross-sectional imaging exams using a published scoring system. Investigators compared EMR and radiologist scores based on the mentioned findings and severity documentation of each variable. Statistical analysis involved means and difference in proportions and logistic regression modeling.

RESULTS

Seventy-three CD patients, with average age 40.6 years (± SD 14.4), having 80 small bowel lesions on imaging were included. EMR reports reliably mentioned within the consensus score included thickness (79%, p = 0.000), enhancement (70%, p = 0.000), active inflammation (86%, p = 0.000), perienteric fluid (82%, p = 0.000), and presence of stricture (62%, p = 0.002). Minimal lumen diameter (19%, p = 0.000), comb sign (19%, p = 0.000), lesion length (57%, p = 0.06), and fistula (50%, p = 1.0) were reported less often. There was a strong association between the EMR and scoring scale in noting severity of active inflammation (88%, p = 0.000), perienteric fluid (76%, p = 0.000), and internal fistula (71%, p = 0.000). The proportion matching severity values of comb sign and minimal lumen were 24% and 21%, respectively (p = 0.000). Severity matches for stricture were less likely among the non-GI radiologists (odds ratio = 0.33, SE = 0.168, p = 0.029). The odds of reporting stricture and fistula severity were 3.6 and 5.7, respectively, on MRE.

CONCLUSIONS

Findings and severity of inflammation were communicated consistently. Stricture severity including minimal luminal diameter, was less reliably reported, though its prognostic significance impacts management.

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.

Acute small intestinal inflammation results in persistent lymphatic alterations

Inflammatory bowel disease (IBD) has a complex pathophysiology with limited treatments. Structural and functional changes in the intestinal lymphatic system have been associated with the disease, with increased risk of IBD occurrence linked to a history of acute intestinal injury. To examine the potential role of the lymphatic system in inflammation recurrence, we evaluated morphological and functional changes in mouse mucosal and mesenteric lymphatic vessels, and within the mesenteric lymph nodes during acute ileitis caused by a 7-day treatment with dextran sodium sulfate (DSS). We monitored whether the changes persisted during a 14-day recovery period and determined their potential consequences on dendritic cell (DC) trafficking between the mucosa and lymphoid tissues. DSS administration was associated with marked lymphatic abnormalities and dysfunctions exemplified by lymphangiectasia and lymphangiogenesis in the ileal mucosa and mesentery, increased mesenteric lymphatic vessel leakage, and lymphadenopathy. Lymphangiogenesis and lymphadenopathy were still evident after recovery from intestinal inflammation and correlated with higher numbers of DCs in mucosal and lymphatic tissues. Specifically, a deficit in CD103⁺ DCs observed during acute DSS in the lamina propria was reversed and further enhanced during recovery. We concluded that an acute intestinal insult caused alterations of the mesenteric lymphatic system, including lymphangiogenesis, which persisted after resolution of inflammation. These morphological and functional changes could compromise DC function and movement, increasing susceptibility to further gastrointestinal disease. Elucidation of the changes in mesenteric and intestinal lymphatic function should offer key insights for new therapeutic strategies in gastrointestinal disorders such as IBD. NEW & NOTEWORTHY Lymphatic integrity plays a critical role in small intestinal homeostasis. Acute intestinal insult in a mouse model of acute ileitis causes morphological and functional changes in mesenteric and intestinal lymphatic vessels. While some of the changes significantly regressed during inflammation resolution, others persisted, including lymphangiogenesis and altered dendritic cell function and movement, potentially increasing susceptibility to the recurrence of gastrointestinal inflammation.