三维超声定量分析胎儿脑干小脑蚓部角及脑干小脑幕角的临床价值

摘要

目的探讨经腹部三维超声定量分析胎儿脑干小脑蚓部BV角、脑干小脑幕BT角在小脑蚓部发育异常疾病鉴别诊断中的应用价值。方法2013年7月至2014年7月对南京医科大学附属苏州市立医院产前超声中心系统超声检查的孕18～34周335例正常胎儿行颅脑超声检查，应用经腹部三维超声获得胎儿小脑蚓部正中矢状切面，测量小脑蚓部BV角和小脑幕BT角，并与16例小脑蚓部发育异常胎儿（典型Dandy-Walker畸形4例，Dandy-Walker变异6例， Blake囊肿6例）相同方法测量的结果进行对照分析。结果335例正常胎儿三维超声测得的BV角为1.0°～10.0°，平均值为（3.3±1.7）°；BT角为16.6°～57.8°，平均值为（31.5±6.9）°。16例小脑蚓部发育异常胎儿三维超声测得的BV角和BT角分别为：（1）4例典型Dandy-Walker畸形胎儿小脑蚓部明显上抬，BV角明显增大，平均值为（88.9±18.1）°，小脑幕上抬，BT角明显增大，平均值为（89.0±12.8）°。（2）6例Dandy-Walker变异胎儿小脑蚓部上旋，BV角增大，平均值为（23.7±5.2）°，BT角稍增大，平均值（54.5±12.0）°。（3）6例Blake囊肿胎儿小脑蚓部上旋，BV角轻度增大，平均值（16.7±1.8）°， BT角稍增大，平均值为（50.3±8.2）°。三维超声测量结果与正常胎儿测量结果相比，Blake囊肿、Dandy-Walker变异、Dandy-Walker畸形胎儿小脑蚓部BV角大于正常组，且随小脑蚓部发育异常程度增加而增加，Dandy-Walker畸形胎儿小脑幕BT角明显增大。结论经腹部三维超声测量BV角和BT角对胎儿小脑蚓部发育异常疾病的鉴别诊断具有重要价值；孕19周后，当BV角大于60°怀疑为Dandy-Walker畸形，BV角大于10°而小于20°时提示可能为Blake囊肿。%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 showed:BV 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.