脑灰质异位的MRI诊断

MRI Diagnosis of Heterotopic Gray Matter of the Brain

目的:分析脑灰质异位的MRI表现,探讨MRI对HGM的诊断价值,以加深对本病的认识,减少漏诊及误诊。材料和方法:回顾分析我院自1996年至2004年21例HGM的MRI表现,并对HGM的病因、分型、常见并发畸形及不同MRI扫描序列与病灶检出率的关系等加以讨论。结果:21例中,病变为双侧4例,单侧17例,多病灶6例,共见异位灰质病灶33个;结节型病灶19个,板层型病灶6个,桥带型病灶8个;病灶位于室管膜下区10个,额叶白质内6个,顶叶白质内5个,枕叶白质内3个,颞叶白质内1个;8个桥带型病灶自室管膜下区通过白质区直达表层灰质区;最小病灶约0.2cm×0.2cm,最大病灶约3.8cm×9.5cm。脑裂畸形11例,胼胝体发育不良4例,巨脑回2例,微脑回1例,透明隔缺如1例,神经上皮囊肿1例,多发性硬化1例。脑室受压变形4例。T1WI、T2WI和PDWI对HGM检查的敏感性分别为47.4%、84.2%和68.4%;准确性分别为39.1%、76.2%和65%。结论:HGM具有特征性的MRI表现,PDWI和T2WI相结合是HGM定量诊断的最佳手段。

Purpose： To analyze the MRI features of heterotopic gray matter of the brain （HGM）, and to investigate the diagnostic value of MRI in HGM so as to deepen the cognition of HGM and to reduce the missed diagnosis and misdiagnose. Materials and Methods： MRI features in 21 patients with HGM in our hospital from 1996 to 2004 were retrospectively analyzed. And the causes, classification, accompanied malformations, the relationship between different sequences and lesion detection rate were also studied. Results： Among all of the 21 cases, the lesions of gray matter heterotopic which were bilateral in 6 cases, unilateral in 17 cases and multiple in 6 cases, were 33 including 19 lesions of nodular type, 6 lesions of grand type and 8 lesions of band type. Of the 33 lesions, 10 located in subependmal zone, 6 in white matter of frontal lobe, 5 in white matter of parietal lobe, 3 in white matter of occipital lobe and 1 in white matter of temporal lobe. 8 band type lesions went through from the subependmal zone to the area of surface gray matter through area of white matter, the smallest lesion was about 0.2cm × 0.4cm, the largest lesion was about 3.8cm × 9.5cm. Of all the 21 cases, 11 patients were accompanied with schizencephaly, 4 with hypogenesis of corpus callosum, 2 with pachygyria, 1 with polygyria, 1 with deletion of septum pellucidum, 1 with neuroepithelial cyst and 1 with multiple sclerosis. Lateral ventrical was compressed and deformed in 4 cases. The sensitivity of HGM detection on T1WI T2WI PDWI were 47.4% 84.2% 68.4%, respectively. The accuracy were 39.1% 76.2% 65%, respectively. Conclusion： HGM has characteristic findings of MRI, proton density weighted imaging（PDWI） and combined- T2WI should be the first choice for quantitatively diagnosing HGM.