胎儿胼胝体发育不全的MRI诊断

MRI diagnosis of fetal corpus callosum agenesis

目的探讨MRI在胎儿胼胝体发育不全(ACC)诊断中的应用价值。方法 39例孕妇,年龄19～35岁;孕龄22～39周,平均29周。产前常规行超声(US)检查后24～48h内行MR检查,采用二维快速平衡稳态采集(2DFIESTA)序列、单次激发快速自旋回波(SSFSE)序列、快速反转恢复运动抑制(FIRM)序列及扩散加权成像(DWI)序列,行胎儿颅脑、胸、腹部常规及颅脑重点冠状面、矢状面及横断面扫描,将产前MRI、US表现与胎儿出生后脑部MRI(20例胎儿)、引产后尸体MRI检查或尸体解剖结果对照(19例胎儿)。结果 39例中完全型ACC32例、部分型ACC7例,单纯ACC31例、合并其他畸形8例。随访结果与产前MRI诊断一致,产前US漏、误诊ACC或合并畸形19例。结论前MRI是胎儿ACC的最理想检查手段,能直接显示胼胝体是否存在,并能较好显示合并的脑部畸形。

Objective： To explore the diagnostic value of MRI on fetal agenesis of corpus callosum （ACC）. Materials and Methods： Thirty-nine pregnant women, aged from 19 to 35 years （average 29 years） and with gestation from 22-39 weeks （average 29 weeks） were studied with a 1.5 T superconductive MR unit within 24 to 48 hours after ultrasound examination. The imaging protocol included fast-imaging employing steady-state acquisition （FIF, STA）, single-shot fast spin echo （SSFSE）, Tl - weighted fast inversion recovery motion insensitive （FIRM） and diffusion-weighted imaging （DWI） sequences in the axial, frontal, and sagittal planes relative to the fetal brain, thorax, abdomen, especially brain. Prenatal US and MR imaging findings were compared with postnatal brain MRI diagnosis （20 fetuses） or postmortem examination （19 fetuses）. Results： In 39 cases of ACC, 32 cases were complete agenesis and 7 were partial agenesis; 31 cases were simple ACC, 8 cases were with other malformations. Follow-up results were consistent with prenatal MRI diagnosis, prenatal US missed or misdiagnosed 19 cases of ACC or combined deformity. Conclusion Fetal MRI is currently the best means of diagnosing ACC. It can directly show the existence of the corpus callosum, and better show the combined brain malformation of ACC.