Antenatal magnetic resonance imaging is useful in providing predictive values for surgical procedures in abdominal wall defects

Development of gastroschisis as seen by magnetic resonance imaging

OBJECTIVES

To describe the magnetic resonance imaging (MRI) morphology and fetal development of gastroschisis.

METHODS

Twenty-seven fetal MRI studies of 24 fetuses (mean gestational age 30 (range, 21-38) weeks), with gastroschisis were retrospectively analyzed. The extra- and intra-abdominal positions of the abdominal organs were assessed on T1- and T2-weighted and steady-state free-precession sequences with emphasis on the intra-abdominal findings.

RESULTS

Third-trimester fetuses (n = 16) showed a uniform morphology: the extracorporeal bowel included jejunum, ileum and colon except for parts of the sigmoid and the rectum. Intra-abdominally the stomach was in contact with the left-sided urinary bladder in 15 of these. Second-trimester fetuses (n = 8) differed with respect to the amount of intra-abdominal bowel and had longer sections of the colon and jejunum intra-abdominally. Intrauterine follow-up (n = 3) demonstrated exteriorization of these bowel segments. Three third-trimester fetuses with gastroschisis complicated by small bowel obstruction, in addition to the dilated small bowel loops, had variable lengths of intra-abdominal colon.

CONCLUSIONS

Fetal development of gastroschisis is a dynamic process lasting until birth. The typical morphology of gastroschisis changes from the second to the third trimester, since intra-abdominal bowel becomes eventrated by the end of the second trimester. This process of eventration is stopped in cases of intestinal stenosis/atresia caused by narrowing of the abdominal wall defect, resulting in different lengths of intra-abdominal bowel. The time when this occurs may correlate with the amount of viable bowel in cases of intestinal atresia. The concept presented here explains the findings in closing gastroschisis.