Isomeric Bodily Situs in the Era of Universal Prenatal Detection: Highlighting Computed Tomographic Findings in Those with Complex Cardiovascular Malformations.

Primarily to identify those with isomeric bodily situs and complex cardiovascular malformations (CCVMs) diagnosed pre- and postnatally from January 2010-December 2024 and report anatomical findings from computed tomography (CT). We identified isomeric bodily situs by ultrasound of upper abdominal inferior caval vein-descending aorta relationships. We identified 91 cases: 65 (71%) with left-isomeric (LI) and 26 (29%) with right-isomeric (RI) bodily situs. Of the 91, 87 had prenatal care, and 86 (99%) were prenatally diagnosed; however, 100% of those with CCVMs were prenatally diagnosed. Of the 91, 78 were live-born. Of the 78, 34 with LI bodily situs had no CCVM, and 44 (24 with LI and 20 with RI) had CCVM. Of the 44, 42 underwent a surgical procedure, and 31/42 (74%) had a preoperative CT scan. Of the 31, 14 had LI bodily situs, in which 79% had left atrial appendage isomerism (LAAI), 79% had left bronchial isomerism, 71% had polysplenia, and 64% had a transverse liver. Of the 31, 17 had RI bodily situs, in which 64% had right atrial appendage isomerism (RAAI), 59% had right bronchial isomerism, 82% had asplenia, and 82% had a transverse liver. Isomeric situses manifest heterogenic thoracoabdominal anatomical features; however, the majority with LI bodily situs had LAAI, left bronchial isomerism, polysplenia, and a transverse liver; and the majority with RI bodily situs had RAAI, right bronchial isomerism, asplenia, and a transverse liver. Further, the prenatal diagnosis was universal in Nevada for those with isomeric bodily situs and CCVMs.