Sonographic features related to volvulus in neonatal intestinal malrotation

This 3 year prospective study evaluated the sensitivity and specificity of abdominal ultrasonography and color Doppler ultrasonography in 31 neonates with suspected malrotation or malrotation with volvulus. Water instillation was used to detect duodenal dilatation, edema, and malrotated bowels. Twenty patients with ultrasonographic characteristics of inversion of the superior mesenteric artery and superior mesenteric vein were later surgically proved to have malrotation. Nine of these 20 patients also had volvulus. Sonographic features suggestive of volvulus included duodenal dilation with tapering configuration (8 of 9 cases, 89%), fixed midline bowel (8 of 9 cases, 89%), whirlpool sign (8 of 9 cases, 89%), and dilation of the distal superior mesenteric vein (5 of 5 cases, 100%). The sensitivity and specificity of duodenal dilation with tapering configuration for detecting volvulus were 89% and 92%, respectively; of fixed midline bowel, 89% and 92%; of whirlpool sign, 89% and 92%; and of dilation of distal superior mesenteric vein, 56% and 73%. The results of this study indicate that ultrasonographic features of inversion of the superior mesenteric artery and superior mesenteric vein could aid in the diagnosis of malrotation, and certain sonographic features can also be used to evaluate volvulus, a condition requiring emergent operation.