Beyond the current limits: a novel approach to differentiate small and large intestine in gastroschisis through...

This study aims to evaluate the ultrasound differentiation of the fetal extra-abdominal small and large intestines in gastroschisis (GS), analyze their diameters and wall thickness across gestational age in simple (sGS) and complex (cGS) cases, and compare findings with normal fetal bowel measurements.

A passive prospective cohort study of fetuses with isolated gastroschisis was performed. Intestinal diameter (extra-abdominal bowel loops diameter, EABL diameter) and bowel wall thickness (extra-abdominal bowel loops wall thickness, EABL wall thickness) were assessed between 26.0 and 34.6 weeks of gestation.

This study included 11 fetuses with cGS and 39 with sGS. Differences in bowel wall appearance between small and large intestines were noted, with a tri-echoic pattern of the small bowel wall observed. We identified clear distinctions between sGS and cGS using measurements of the small and large bowel. Normal fetal small bowel and colon diameters were inadequate for assessing bowel measurements and diagnosis bowel dilatation in gastroschisis, highlighting the need for gastroschisis-specific reference values.

We have demonstrated that it is possible to distinguish a small bowel from a large bowel by assessing intestinal position and arrangement and by visualising the "three-line appearance" of the small bowel wall. The small and large bowel measurements in fetuses with gastroschisis differ and increase with gestation. The thickness of the small bowel wall changes during pregnancy and increases with gestation, while the wall thickness of the large intestine remains almost unchanged. Proper distinguishing the small and large intestine in fetuses with GS allows for accurate diagnosis of bowel dilation.