Bowel Wall Visualization Using MR Enterography in Relationship to Bowel Lumen Contents and Patient Demographics

Abstract

Background MR enterography (MRE) is generally performed without bowel preparation, but the frequency and extent by which bowel contents affect bowel wall visualization are poorly described in the literature. Purpose To evaluate MRE bowel wall visualization quality relative to bowel lumen contents and patient demographics. Study Type Retrospective, single‐center. Population One hundred and four consecutive patients (mean age 29 years, range 5–76 years) without prior bowel resection who had undergone MRE. Field Strength/Sequence 3 T (N = 87) or 1.5 T (N = 17)/T2‐weighted single‐shot spin echo (T2WI) and fat‐saturated T1‐weighted gradient echo (T1WI) without and with gadolinium. Assessment For the proximal and distal jejunum and ileum and colon, three readers independently categorized bowel lumen signal (water = bright T2 dark T1, T1‐bright, or air = dark T2 and T1 signal) and scored distension (0 = poor, 1 = moderate, 2 = well) and wall enhancement (0 = unclear, 1 = perceptible, 2 = clear) based upon gadolinium enhanced T1WI for the 104 MRE exams). The bowel visualization score was the sum of the wall enhancement and distension scores and was considered adequate if ≥3. Statistical Tests Wilcoxon signed‐rank test. Results The bowel lumen content was water signal in 93% (97/104 scans), 92% (95/104), 98% (102/104), and 93% (92/104) of the proximal and distal jejunum and proximal and distal ileum, respectively, but only in 12.5% (13/104) of the colon. There was adequate bowel visualization of 53.8%, 77.8%, 84.6%, 90.4% of the proximal and distal jejunum and proximal and distal ileum, respectively, but only 19.2% of the colon. In children (age < 18 years), the visualization score of the ileum was lower when the adjacent colon contained air (2.4 ± 0.97) compared to water (3.75 ± 0.29, P < 0.05) or T1‐bright material (3.21 ± 0.82, P < 0.05). Data Conclusion Without bowel preparation, colon wall visualization was often unsatisfactory at MRE, and air‐filled colon also degraded small bowel visualization, particularly in children. Level of Evidence 4 Technical Efficacy Stage 1

Feasibility of IntestinalMRElastography in Inflammatory Bowel Disease

“…The lack of an accurate noninvasive diagnostic test restricts patient management, therapy monitoring and stratification in clinical trials. Noninvasive surrogate markers are warranted to replace invasive diagnostic procedures 5–7 …”

Editorial for “Bowel Wall Visualization Using MR Enterography in Relationship to Bowel Lumen Contents and Patient Demographics”

“…This may be of concern for patients undergoing MRE who have IBD, which primarily affects the colon 8 . Zhang et al 7 also reported that air‐containing bowel in the colon compromised the bowel wall visualization in small bowel regions, particularly in children, which is contrary to the findings from Sinha et al 6 Moreover, Crohn's disease affects the colon of 56% of pediatric patients compared to 23% of adult patients with penetrating disease 9 . Thus, to minimize image misinterpretations based on colon content, Zhang et al suggest that bowel cleansing may be appropriate prior to MRE for patients where colonic involvement might be of concern 7 …”

“…6 In this issue of JMRI, a research article by Zhang et al explored bowel wall visualization using MRE in relation to the bowel lumen content. 7 They conducted a retrospective study in a cohort of adult and pediatric patients who underwent MRE without any bowel cleansing preparation. GI radiologists reviewed the images (T2-weighted images and T1-weighted images with and without gadolinium) and assessed the bowel lumen content, and graded the degree of bowel distension and quality of wall enhancement for different segments of the intestinal tract.…”

“…9 Thus, to minimize image misinterpretations based on colon content, Zhang et al suggest that bowel cleansing may be appropriate prior to MRE for patients where colonic involvement might be of concern. 7 Even though bowel cleansing may be a discomfort for some patients prior to MRE, the benefit of an accurate and timely diagnosis can significantly impact the clinical outcome. In the context of differentiating fibrotic and inflammatory strictures using MRE, diffusion-weighted imaging and magnetization transfer imaging are techniques that have shown potential in distinguishing fibrotic and inflammatory stenosis in patients with Crohn's disease.…”

“…In this issue of JMRI , a research article by Zhang et al explored bowel wall visualization using MRE in relation to the bowel lumen content 7 . They conducted a retrospective study in a cohort of adult and pediatric patients who underwent MRE without any bowel cleansing preparation.…”