A novel method to improve prenatal diagnosis of abnormal systemic venous connections using three- and four-dimensional ultrasonography and 'inversion mode

Objective The precise prenatal diagnosis of abnormal venous connections of the fetal heart is challenging. Anatomical accuracy may be important in determining the best route for postnatal angiograpby, as well as the prognosis and treatment. This study was designed to determine the value of 'inversion mode, a new three-and four-dimensional (4D) rendering algorithm, in the visualization of the spatial relationships of an interrupted inferior vena cava (IVC) with azygos or hemiazygos vein continuation associated with and without heterotaxic syndromes. Methods Heart volumes were acquired using 4D ultrasonography and spatiotemporal image correlation in cases of interrupted IVC with azygos/hemiazygos continuation (n = 3). Volume datasets were rendered using the 'inversion mode' algorithm and abnormal images were compared to those generated from a library of normal fetuses. Results The 'inversion mode' rendering algorithm allowed the visualization of dilated azygos or hemiazygos veins and their spatial relationships with the descending aorta, the aortic arch, the superior vena cava, and the atria in cases of interrupted I VC with and without heterotaxic syndromes. Conclusions The 'inversion mode' algorithm improves prenatal visualization of both dilated azygos and hemiazygos veins, as well as their spatial relationships with the surrounding vascular structures. This has implications for the accurate prenatal diagnosis and management of neonates with abnormal systemic venous connections. Copyright (c) 2005 ISUOG. Published by John Wiley & Sons, Ltd.