脑灰质异位磁共振扩散张量成像的定量研究

目的：探讨脑异位灰质及其周边白质纤维束在磁共振扩散张量成像中的影像特点。方法：回顾性分析10例经MRI证实的脑灰质异位患者DTI图像。观察DTI及DTT图像灰质异位区周围脑白质形态，并在DTI图像上测量异位灰质及其周围脑白质、对侧脑白质及正常位置脑灰质各向异性分数（FA）值，比较异位灰质区脑白质与对侧大脑半球相同位置脑白质是否有统计学差异，并比较异位灰质区与正常位置灰质是否有统计学差异。结果：10例患者中Ⅰ型室管膜下型灰质异位有2例；Ⅱ型皮层下灰质异位有5例；Ⅲ型带状性灰质异位有1例；兼有上述两种或两种以上又出现Ⅳ型即混合型有2例。异位灰质区脑白质走行发生异常，呈受压推移或聚拢改变，无消融；异位灰质区脑白质与对侧大脑半球相同位置脑白质区的FA值间的差异无统计学差异（T=-0.435，P=0.669）；异位灰质区与正常位置灰质间的FA值大致相同（T=-0.000，P=1.000）。结论：异位灰质区白质纤维束形态发生改变，FA值与对侧白质纤维束相比，无明显下降；DTT可清晰显示异位灰质区脑白质的走行方向及形态。

MRI diffusion tensor imaging in patients with heterotopic gray matter:a quantitative study

Objective：To discuss the imaging characteristics of cerebral heterotopic gray matter tissues and the white matter fiber bundle on peri-heterotopic gray matter in MRI diffusion tensor imaging（DTI）.Methods：Ten patients with heterotopic gray matter confirmed by MRI were examined DTI.To observe the white matter fiber bundles in peri-heterotopic gray matter,and the fractional anisotropy（FA） values were measured on the heterotopic gray matter and the surrounding white matter.In addition,the FA value of the contralateral normal cerebral white matter and gray matter were measured,respectively,to compared the FA values between the white matter fiber bundle on peri-heterotopic gray matter and the contralateral normal cerebral white matter.The heterotopic gray matter were compared with the normal gray matter area.Results：Ten patients with Ⅰ type in 2 cases;Ⅱ type in 5 cases;Ⅲ type in 1 case;Ⅳ type in 2 cases.There was basic change of the white matter fiber bundle at peri-heterotopic gray matter appeared as displaced or gathering together damage;there was no significant difference for FA value between the white matter fiber bundle at the peri-heterotopic gray matter and the contralateral normal position cerebral white matter（T=-0.435,P=0.669）;the FA value between ectopic location of gray matter and normal gray area had no significant difference（T=-0.000,P=1.000）.Conclusion：The white matter fiber bundle on peri-heterotopic gray matter has morphological abnormality,FA value has no significant decrease compared with that of the contralateral white matter fiber tracts;DTT can clearly show the direction and morphology of white matter in the ectopic gray matter.