Benign Structural and Functional Abnormality of the Small Bowel

Abstract

A torsion of the small bowel leads to small bowel volvulus with various etiologies such as congenital midgut malrotation, anatomical derangements, inflammatory conditions, and tumors. Congenital midgut volvulus is typically encountered within the first month of life with pathognomonic imaging features including corkscrew sign and whirlpool sign. Meckel diverticulum, a congenital anomaly caused by incomplete atrophy of omphalomesenteric duct, is found on the antimesenteric border of distal ileum. Heterotopic gastric mucosa in the Meckel diverticulum may induce complications including inflammation, ulceration, perforation, and hemorrhage. Protein-losing enteropathy has a variety of causes: erosive disease such as Crohn’s disease, nonerosive disease such as systemic lupus erythematosus, and disease with increased interstitial pressure such as intestinal lymphangiectasia. Intestinal lymphangiectasia is usually seen as diffuse nonspecific bowel wall thickening and sometimes depicted with halo sign consisting of hypodense inner layer representing dilatation of lymphatic vessels and hyperdense muscular/serosal layer on contrast-enhanced CT.