HDlive imaging of meconium peritonitis.

Abstract

Prenatal two-dimensional (2D) sonographic diagnostic criteria for meconium peritonitis include polyhydramnios, bowel dilatation, abdominal calcification or echogenic mass and fetal ascites1. However, its diagnosis is still challenging, not only because these findings observed on ultrasound do not present simultaneously2, but also because the clinical picture varies according to the underlying etiology, the interval between intestinal perforation and its finding on ultrasound, and subsequent inflammatory reaction3. A 33-year-old Japanese primigravida was referred to our hospital at 32 + 2 weeks' gestation because of polyhydramnios and fetal bowel dilatation. 2D sonography (Voluson E8, GE Medical Systems, Zipf, Austria) revealed a single breech fetus with biometry consistent with gestational age and an amniotic fluid index of 9.04 cm. Cystic dilatation of the intestine with thick hyperechogenic wall denoting calcification and fine hypoechoic granular contents were observed in the fetal abdomen (Figure 1). Two weeks later, three-dimensional (3D) ultrasound in conjunction with HDlive mode revealed that the wall of the dilated intestinal loops was irregularly thickened, and that there was meconium within them (Figure 2, Videoclip S1). 3D sonography with HDlive inversion mode showed clearly that the cystic intestinal dilatations of the small intestine were continuous with one another, and that there were irregularities in caliber size (Figure 3). These findings were suggestive of fetal meconium peritonitis. Emergency Cesarean section was performed 2 weeks later, owing to premature rupture of the membranes and the fetus being in breech presentation. A 2525-g female, 46.5 cm in length, with Apgar scores of 8 and 9 at 1 and 5 min, respectively, and umbilical artery pH of 7.236, was delivered. Neonatal resuscitation with a nasogastric tube revealed meconium in the aspirate. Plain X-ray of the neonate on the first postnatal day identified abdominal calcification, confirming the diagnosis of meconium peritonitis. Emergency exploration was performed, revealing the presence of pus and marked intraperitoneal adhesions (Figure 4). The neonate underwent subsequent intra-abdominal drainage and lavage. Soon afterwards, definitive surgery was performed and the baby followed a favorable course. The HDlive technique uses an adjustable light source, creating light and shadow effects, thereby increasing depth perception4, enabling realistic images to be obtained. 3D inversion mode is used to visualize fluid-filled structures that cannot normally be seen accurately using 2D sonography5. In the present case, dilatations of the small intestine were identified clearly and the dilated loops were seen to have irregularities in caliber. Moreover, using this mode, the continuity and curvature of the bowel were demonstrated better than by 2D sonography. Irregular fetal intestinal wall thickness, with the presence of meconium inside the intestine, and caliber changes are caused by meconium ileus, unlike in ileal atresia, in which the intestine has a regular caliber. This differentiation, which is almost impossible to detect by 2D sonography, is important because each condition has a different management strategy. Moreover, meconium peritonitis seems to be more readily discernible on HDlive images than on those obtained by 3D ultrasound because of its shadowing effect. In conclusion, to the best of our knowledge, this is the first report of HDlive and HDlive inversion mode used to construct images of and diagnose meconium peritonitis in a 34-week fetus. We recommend the use of HDlive in the prenatal diagnosis of meconium peritonitis as a complementary tool to conventional 2D sonography. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.