P. Volpe

To explore whether the use of four dimensional (4D) ultrasound examination with B-flow imaging and spatiotemporal image correlation (STIC) can supply additional information with respect to two-dimensional (2D) gray-scale and color Doppler echocardiography in the prenatal characterization of isolated total anomalous pulmonary venous connection (TAPVC). The study population comprised a group of three TAPVC fetuses that had been examined exclusively by conventional echocardiography, and a group of four additional cases initially identified by conventional echocardiography and examined further by 4D ultrasonography; a thorough postnatal work-up was available for all fetuses. At our center, isolated TAPVC was found in seven of 1040 fetuses with cardiac defects (0.67%). Anomalous drainage was supracardiac to the innominate vein in three cases, cardiac to the coronary sinus in two, and infracardiac to the portal vein in the remaining two cases. An evident asymmetry between left heart and right heart structures was observed in 4/7 cases. The confluence of the anomalous pulmonary veins (PVs) was visualized in 4/7 cases and the connecting vertical vein was identified in 3/5 cases at 2D echocardiography. 4D ultrasound imaging with B-flow imaging and STIC clearly visualized the anomalous PV confluence and the draining vertical vein in all four cases examined. 2D and color Doppler echocardiography appears to diagnose reliably TAPVC, albeit with some limitations in thorough assessment of the pathology, depending on the anatomy of the defect, on the technical adequacy of the equipment used and on the experience of the operator. 4D ultrasound examination with B-flow imaging and STIC is apparently able to facilitate identification of the anatomical features of TAPVC, thus supplying additional information over that provided by 2D fetal sonography.

To evaluate the role of the brainstem-vermis (BV) angle in the diagnosis of fetal posterior fossa abnormalities at 15-18 weeks' gestation. We examined retrospectively three-dimensional (3D) ultrasound volumes acquired at 15-18 gestational weeks in fetuses with normal posterior fossa (controls) and in those with cystic posterior fossa. Whether the fourth ventricle appeared open posteriorly in axial views was noted and the BV angle was measured. A detailed follow-up was obtained in all cases. Of the 139 controls, 46 cases were excluded because of inadequate quality of the 3D volumes. Of the 93 remaining normal fetuses, 84 (90.3%) had a closed fourth ventricle and a BV angle < 20°, whereas 9/93 (9.7%) had an open fourth ventricle and a BV angle between 20° and 37°. The study group of 11 fetuses included seven with Dandy-Walker malformation and four with Blake's pouch cyst. In abnormal cases as a whole, the BV angle was significantly increased compared with that in controls (P < 0.0001). However, fetuses with Blake's pouch cyst and normal fetuses with an open fourth ventricle had strikingly similar sonograms: the BV angle was between 20° and 37° and the fourth ventricle appeared open only when viewed using a more steeply angulated scanning plane than that of the standard transcerebellar plane; in fetuses with Dandy-Walker malformation the fourth ventricle was widely open posteriorly, even in the standard transcerebellar view, and the BV angle was > 45°, significantly increased compared both with that in normal fetuses (P < 0.0001) and with that in fetuses with Blake's pouch cyst (P = 0.004). An open fourth ventricle is found in about 10% of normal fetuses at 15-18 weeks' gestation. Measurement of the BV angle is useful in such cases, as a value ≥ 45° is associated with a very high risk of severe posterior fossa malformation.