MRI reveals different Crohn's disease phenotypes in children and adults.

OBJECTIVES: To identify differences between two cohorts of adult and pediatric patients affected by Crohn's disease (CD), with regard to lesion location in the small intestine and colon-rectum, lesion activity, and prevalence of perianal disease (PD), using MRI as the main diagnostic tool. METHODS: We retrospectively reviewed 350 consecutive MRI examinations performed between 2013 and 2016 in outpatients or inpatients with histologically proven CD, monitored by the Gastroenterology and Pediatric Units of our Hospital. The magnetic resonance enterography (MRE) protocol for adult and pediatric CD patients routinely includes evaluation of nine different intestinal segments (from jejunum to rectum) and of the anal canal. Intestinal activity was also calculated using a validated score. Perianal disease (PD) was staged. Fisher's exact test was used and the odds ratio (OR) was calculated. RESULTS: Two hundred and nineteen out of 350 MRI studies (118 adults and 101 children) were included. The prevalence of PD was 34.6% in children and 16.1% in adults (OR = 2.8; p = 0.0017). Pediatric patients showed more frequent rectal involvement (29.7% vs 13.5%, OR = 2.7; p = 0.0045) and higher risk of PD in the presence of rectal disease (p = 0.043; OR = 4.5). In pediatric patients with severe colorectal disease, the prevalence of PD was twofold (86.7% vs 40%; p = 0.072). Using the clinical Montreal classification for lesion location, no significant differences emerged between the two patient populations. CONCLUSIONS: MRI showed a significantly higher prevalence of rectal involvement and perianal disease in the pediatric population. These results may have a relevant clinical impact and deserve further investigation. KEY POINTS: • To our knowledge, this is the largest morphological comparative study available in the literature using MRI as the main diagnostic tool to compare adult patients and children with Crohn's disease. • Our study showed significant differences between adults and children: a higher prevalence of rectal and perianal fistulous disease (PD) in pediatric patients and an increased prevalence of PD in the presence of severe colon-rectum involvement. • The association of rectal and perianal disease implies a poorer clinical prognosis and a higher risk of disabling complications in pediatric patients.

Prospective Comparison between two different magnetic resonance defecography techniques for evaluating pelvic floor disorders: air-balloon versus gel for rectal filling.

PURPOSE: to prospectively compare two rectal filling techniques for dynamic MRI of pelvic floor disorders (PFD). METHODS AND MATERIALS: Twenty-six patients with PFD underwent the two techniques during the same procedure, one based on rectal placement of a balloon-catheter filled with saline and air insufflation (air-balloon technique or AB); another based on rectal filling with 180 cc of gel (gel-filling technique or GF). The examinations were compared for assessment and staging of PFD, including rectal-descent, rectocele, cystocele, colpocele, enterocele, rectal invagination. Surgery and clinical examinations were the gold standard. RESULTS: AB showed sensitivity of 96 % for rectal descent, 100 % for both rectocele and colpocele, 86 % for rectal invagination and 100 % for enterocele; understaged 11 % of rectal descents and 19 % of rectoceles. GF showed sensitivity of 100 % for rectal descent, 91 % for rectocele, 83 % for colpocele, 100 % for rectal invagination and 73 % for enterocele; understaged 3.8 % of rectal descent and 11.5 % of rectoceles. Both techniques showed 100 % of specificity. Agreement between air-balloon and gel filling was 84 % for rectal descent, 69 % for rectocele, 88 % for rectal invagination, 84 % for enterocele, 88 % for cystocele and 92 % for colpocele. CONCLUSION: Both techniques allowed a satisfactory evaluation of PFD. The gel filling was superior for rectal invagination, the air-balloon for rectocele and anterior/middle compartment disorders. KEY POINTS: • A standardized MRI technique for assessing pelvic floor disorders is not yet established. • This study compares two MRI techniques based on different rectal filling: air-balloon versus gel. • Both MRI techniques proved to be valuable in assessing PFD, with good agreement. • Air-balloon technique is more hygienic and better tolerated than the gel-filling technique. • Gel was superior for rectal invagination, air-balloon for rectocele and uro-genital prolapses.

Detection of Crohn disease lesions of the small and large bowel in pediatric patients: diagnostic value of MR enterography versus reference examinations.

OBJECTIVE: The purpose of this article is to prospectively determine the accuracy of MR enterography in detecting Crohn disease lesions from the jejunum to the anorectal region in pediatric patients, in comparison with main reference investigations. SUBJECTS AND METHODS: Fifty consecutive children with known Crohn disease underwent MR enterography with oral contrast agent and gadolinium-chelate intravenous injection. Two radiologists detected and localized lesions by dividing the bowel into nine segments (450 analyzed segments in 50 patients). Ileocolonoscopy, barium studies, intestinal ultrasound, and capsule endoscopy were considered as first- and second-level reference examinations and were performed within 15 days of MR enterography. RESULTS: MR enterography detected lesions in 164 of 450 segments, with 155 true-positive and nine false-positive findings; overall sensitivity, specificity, and positive and negative predictive values for small- and large-bowel lesions were 94.5%, 97%, 94.5%, and 97%, respectively (ĸ = 0.93; 95% CI, 0.89-0.97). Sensitivity and specificity values were 88% and 97%, respectively, for the jejunum, 100% and 97% for the proximal-to-mid ileum, 100% and 100% for the distal ileum, 93% and 100% for the cecum, 70% and 97% for the ascending colon, 80% and 100% for the transverse colon, 100% and 92% for the descending colon, 96% and 90% for the sigmoid colon, and 96% and 88% for the rectum. From jejunum to rectum, the AUC value ranged between 0.916 (jejunum) and 1.00 (distal ileum). Perianal fistulas were diagnosed in 15 patients, and other complications were found in 13 patients. CONCLUSION: MR enterography showed an accuracy comparable to that of reference investigations, for both small- and large-bowel lesions. Because MR enterography is safer and more comprehensive than the reference examinations, it should be considered the primary examination for detecting Crohn disease lesions in children.