Prenatal diagnosis of antenatal midgut volvulus: Specific ultrasound features

To assess specific, direct, and indirect prenatal ultrasound features in cases of fetal midgut volvulus.

Retrospective case series of neonatal volvulus, based on postnatal and prenatal imaging findings that occurred from 2006-2017. Prenatal and postnatal signs including the specific "whirlpool sign" were computed. Postnatal volvulus was confirmed by pathology examination after surgery or neonatal autopsy.

Thirteen cases of midgut volvulus were identified. Though not a specific sign, a decrease in active fetal movements was reported in eight patients (61.5%). The prenatal whirlpool sign was directly seen in 10 cases, while an indirect but suggestive sign, a fluid-filled level within the dilated loops, was present in five cases. No intestinal malrotation was observed. Pregnancy outcomes were two terminations of pregnancy, both associated with cystic fibrosis, one early neonatal death, three prenatal spontaneous regressions, and seven favorable outcomes after neonatal surgery with resection of midgut atresia.

Identification of the whirlpool sign or of a fluid-filled level within the dilated loops improves the accuracy of ultrasound findings for suspected volvulus. In the absence of total volvulus (in cases of intestinal malrotation) or association with cystic fibrosis, the prognosis appears good.