胎儿前脑无裂畸形经典类型的MRI诊断

目的探讨MRI在胎儿前脑无裂畸形(HPE)经典类型诊断中的应用价值。方法12例孕妇,年龄17~37岁;孕龄21~35周,平均26周。产前常规行超声检查后72 h内行MRI检查共同诊断为HPE胎儿。采用二维快速平衡稳态采集(2D FIESTA)序列、单次激发快速自旋回波(SS-FSE)序列,行胎儿颅脑冠状位、矢状位及轴位扫描。将产前MRI表现与引产后尸体MRI检查或尸体解剖结果对照。结果12例中无叶型HPE 1例,产前MRI表现为透明隔间腔缺如,双侧脑室融合,深部灰质核团融合,可见背侧囊结构,合并眼距过窄及长鼻畸形;半叶型HPE 3例,产前MRI表现为双侧脑室融合,侧脑室额角缺如,深部灰质核团不同程度融合;叶型HPE 8例,产前MRI表现为双侧脑室融合,部分侧脑室额角形态异常,部分丘脑、下丘脑融合。12例HPE胎儿中合并眼距过窄及长鼻畸形1例。结论经典类型HPE的MRI表现具有特征性,有助于HPE的产前诊断,提高HPE的产前检出率。

MRI Diagnosis of the Classic Forms of Fetal Holoprosencephaly

Objective To explore the diagnostic value of MRI in the classic forms of fetal Holoprosencephaly.Methods 12 pregnant women,aged from 17 to 37 years(average 26 years)and with gestation from 21-35 weeks(average 26 weeks)were studied with a 1.5 T superconductive MRI unit within 72 hours following ultrasound examination.The imaging protocol included fast-imaging employing steady-state acquisition(FIESTA),single-shot fast spin echo(SSFSE)sequences in the axial,frontal,and sagittal planes relative to the fetal brain.Prenatal MR imaging findings were compared with postmortem examination.Results Among the 12 cases,1 case was diagnosed as alobar HPE.The prenatal MRI showed absence of cavum septum pellucidum,bilateral ventricular fusion,deep gray matter nucleus fusion,presence of a dorsal cyst,combined with ocular hypotelorism and proboscis.3 cases were diagnosed as semilobar HPE.Prenatal MRI showed bilateral ventricular fusion,absence of frontal horn of lateral ventricles,and fusion of deep gray matter nuclei in different degrees;8 cases were diagnosed as lobar HPE.Prenatal MRI showed bilateral ventricular fusion,some frontal horn abnormalities,and some thalamic and hypothalamic fusion.Conclusion The MRI features of the classic type of HPE are characteristic,and MRI can show the pathological features of the classic type of HPE,which contributes to the prenatal diagnosis of HPE.