Role of magnetic resonance in bowel pathologies: Beyond inflammatory bowel disease

Table 1 Magnetic resonance imaging sequences, contrast requirements, key imaging findings, and main clinical indications for non-inflammatory bowel disease bowel pathologies

Condition	MRI sequences						IV contrast	Key findings	Main clinical indication
	T2/HASTE	T1	DWI	Post-Gd T1	MRE/enteric	MRA/flow
Celiac disease	√							Bowel dilatation; mural thickening; submucosal edema; jejunoileal fold pattern reversal; jejunization of ileum; lymphadenopathy	Not routine for diagnosis; problem-solving in nonspecific symptoms
Appendicitis	√		√					Dilated, fluid-filled appendix; wall thickening/T2 hyperintensity due to edema; periappendiceal inflammation; restricted diffusion	Equivocal US, particularly children or pregnancy
Diverticulitis	√	√	√					Diverticula; wall thickening; pericolonic fat stranding; phlegmon/abscess; perforation or fistula	Alternative in selected patients with suspected diverticulitis
Radiation enteritis	√			√	√		√	Wall thickening; mural enhancement; luminal narrowing; strictures; chronic obstruction	Post-radiotherapy abdominal symptoms or suspected chronic radiation enteropathy
Radiation colitis/proctitis	√			√			√	Wall thickening/T2 hyperintensity due to edema; mural enhancement; luminal narrowing; fibrosis/strictures; presacral or mesorectal fascial change	Suspected large-bowel radiation injury after pelvic irradiation
Fistulas	√	√		√			√	Fistulous tract; focal wall thickening; debris/air; fat stranding; abscess or fluid collections; pelvic-organ involvement	Define tract anatomy and associated complications
Bowel neoplasms	√	√		√	√		√	Annular/constricting lesion; polypoid intraluminal mass; exophytic mass; segmental thickening; obstruction, nodes, hemorrhage, necrosis	Detect, characterize, and stage bowel lesions and complications
Pouchitis	√	√		√			√	Pouch wall thickening > 2 mm; abnormal mural enhancement; peripouch fat infiltration; fluid collection or abscess; sinus tract or fistula	Evaluate mural inflammation and extraluminal complications after ileal pouch-anal anastomosis
Bowel obstruction	√	√			√			Dilated proximal loops; transition point; adhesions; collapsed distal bowel; visible obstructing cause when present	Radiation-sparing alternative in children, pregnancy, or high cumulative exposure risk
Intussusception	√				√			Bowel-within-bowel configuration; hyperintense intraluminal fluid; low/intermediate wall signal; perienteric edema; lead point	Problem-solving or incidental detection; assess obstruction or a lead point
Mesenteric ischemia	√			√		√	√	Mural thickening/edema; reduced or absent enhancement; mesenteric edema/ascites; vascular filling defect; pneumatosis or portomesenteric gas in severe cases	Best established for chronic mesenteric ischemia; MRA and flow MRI assess stenosis and postprandial flow

√: May be used for evaluation; Blank: Not routinely used or required for that indication; DWI: Diffusion-weighted imaging; Gd: Gadolinium; HASTE: Half-Fourier acquisition single-shot turbo spin-echo; IV: Intravenous; MRA: Magnetic resonance angiography; MRE: Magnetic resonance enterography; MRI: Magnetic resonance imaging; US: Ultrasound.