Appearance of fetal intestinal obstruction on fetal MRI

To retrospectively analyze the imaging findings of fetal intestinal obstruction diagnosed by MRI and compare with postnatal surgery findings.

MRI data of 3346 pregnant women were retrospectively analyzed; we found 47 cases of suspected fetal small intestinal obstruction. Twenty-nine underwent postnatal surgery.

We identified one case of jejunal obstruction secondary to perforation, five annular pancreas, 10 duodenal stenoses, four jejunal stenoses, five jejunal atresias, two ileal atresias, four intestinal volvulus, and four intestinal malrotations. We further found four cases of duodenal stenosis with intestinal malrotation (two cases also showed volvulus). On fetal MRI, annular pancreas and duodenal obstruction manifested as a "double bubble." Jejunal stenosis appeared as a "triple bubble." Jejunal and ileal atresia mainly manifested as proximal dilatation with high signal on T1WI. Intestinal volvulus showed a sausage-like intestinal distortion and mixed signals on T1WI and DWI sequences. Intestinal malrotations were characterized as abnormal duodenal morphology. We missed two malrotations; one jejunal obstruction was misdiagnosed.

Prenatal MRI can accurately determine the degree of intestinal obstruction and help qualitatively diagnose its possible etiology according to changes in MRI signals in multiple sequences, providing guidance for prenatal counseling.