柔脑膜转移的MRI诊断价值

目的 探讨柔脑膜转移的解剖基础、转移途径和MRI的诊断价值。方法 29例病人均行横轴位、矢状位T1WI，横轴位T2WI和横轴位FLAIR平扫。团状注射Gd—DTPA0．2mol／kg后行横轴位、矢状位T1WI和冠状位T1WI抑制脂肪序列增强扫描。结果 脑实质转移灶伴柔脑膜线状增厚、增强影占17．24％。脑实质转移灶伴柔脑膜结节灶及线状增厚、增强影占24．14％。柔脑膜结节灶及线状增厚、增强影13．79％。单纯柔脑膜结节灶6．90％。单纯柔脑膜线状增厚、增强影13．79％。沿室管膜以及柔脑膜线状增厚、增强影13．79％。脑实质转移伴柔脑膜以及颅神经脑池段增厚、增强影10．34％。结论 柔脑膜的解剖结构、血供特点和脑脊液循环决定了柔脑膜即可发生血源性转移又可发生脑脊液源性转移。恶性肿瘤怀疑柔脑膜转移的病人必须行MRI增强检查，以免漏诊。

MRI Evaluation of Leptomeningeal Metastases

Objective To discuss the anatomic basis, transfer pathway and MRI features of leptomeningeal metastases. Methods Axial, sagittal T1WI, T2WI and axial FLAIR plain scans were performed in 29 patients. Axial, sagittal T1WI and coronal T1WI fat suppression after injection of Gd-DTPA 0.2mol/kg were taken. Results Both cerebral metastases and leptomeningeal linear thickening were seen in 17.24%, cerebral metastases with leptomeningeal nodular or linear thickening in 24.14%, leptomeningeal nodular and linear thickening in 13.79%, leptomeningeal nodules in 6.90%, leptomeningeal linear thickening in 13.79%, linear thickening of ependyma and leptomeninge in 13.79%,cerebral and leptomeningeal as well as cranial nerve metastases in 10.34%. Conclusion Both hematogenous and CSF metastases occur at the leptomeningeal membrane depending on its anatomic basis and blood supply. MRI examinations with Gd-DTPA must be done in patients with malignant tumor in case of missed diagnosis.