The value of quantitatively fetal brainstem-vermis and brainstem-tentorium angles evaluation by three-dimensional ultrasonography / 中华医学超声杂志（电子版）

ABSTRACT

Objective To evaluate the role of fetal brainstem-vermis (BV) and brainstem-tentorium (BT) angles in differential diagnosis of fetal cereballar vermis anomalies by three-dimensional ultrasonography. Methods A total of 335 normally developed fetuses at 18-34 gestational weeks were examined prospectively in Prenatal Ultrasound Center of Suzhou Municipal Hospital from July 2013 to July 2014 by three-dimensional ultrasonography scanning. The BV angles and BT angles were measured at the mid-sagittal sections of fetal heads which were obtained by three-dimensional ultrasonography. Sixteen fetuses with abnormal cerebellar vermis were selected. The BV angles and BT angles were measured and compared with the measurements of normal group. Results In normal fetuses, the mean of BV angles was (3.3±1.7)° , ranging from1.0 to 10.0°;the mean BT angle was (31.5±6.9)° , and ranging from 16.6 to 57.8° . In 16 cases of abnormal cerebellar vermis, 4 cases of Dandy-Walker Malformation (DWM) showed significantly upward rotated cerebellar vermises, the BV angles increased significantly (88.9±18.1)° , the cerebellar tentoriums were superior displaced, the BT angles increased remarkably (89.0±12.8) ° ;6 cases of Dandy-Walker variant (DWV) showed upward rotated cerebellar vermises, with increased BV angles (23.7±5.2) ° , and slightly increased BT angles (54.5±12.0)°;6 cases of Blake′s pouch cyst (BPC) showed upward rotated cerebellar vermises were, mildly increased BV angles (16.7±1.8)° , and slightly increased BT angles (50.3±8.2)° . The comparison results showedBV angles increased with increasing severity of the condition in BPC, DWV and DWM;BT angles increased significantly in DWM. Conclusions The measurements of BV angles and BT angles are valuable in the differential diagnosis of fetal cereballar vermis anomalies. From 19 gestational weeks, a BV angle>60° is strongly suggestive of a Dandy-Walker malformation, while a measurement>10.0° and<20° favors the diagnosis of Blake′s pouch cyst.