灌注加权磁共振成像在颅内肿瘤诊断中的应用

Preliminary Study on Perfusion-weighted MR Imaging in the Diagnosis of Intracranial Tumors

目的 :评价灌注加权磁共振成像 (PWI)在颅内肿瘤诊断中的价值。方法 :采用GRE EPI序列 ,对 5 0例颅内肿瘤患者行注射对比剂 (Gd DTPA)后的PWI,根据PWI获得的信号强度 时间曲线重建相对脑血容量 (rCBV)图和对比剂相对平均通过时间 (rMTT)图 ,计算各个肿瘤与对侧正常脑白质最大rCBV比值和rMTT比值。结果 :脑膜瘤、转移瘤、胶质瘤的平均最大rCBV比值分别为 8 77±6 94、5 2 1± 1 91、2 79± 1 49,三者差异有统计学意义 (P <0 0 1)。脑膜瘤中以血管瘤型最高 ,明显高于其他亚型 (P <0 0 5 )。Ⅲ～Ⅳ级胶质瘤rCBV比值较Ⅰ～Ⅱ级明显升高 (P <0 0 1)。各肿瘤rMTT比值均较对侧正常脑白质升高。不同肿瘤间rMTT比值未见明显差异。结论 :rCBV比值的半定量研究有助于观察肿瘤组织的血供和确切范围 ,在胶质瘤恶性度判别及脑内外肿瘤的鉴别上PWI具有很高的价值。

Aim:To valuate the role of perfusion-weighated MR imaging (PWI) in the diagnosis of intracranial tumors.Methods:50 patients with intracranial tumors underwent perfusion-weighted MR imaging with GRE-EPI sequence after administration of contrast media (Gd-DTPA).Maps of relative regional blood volume (rCBV) and relative regional mean transit time (rMTT) were computed according to the signal intensity-time curves.The maximal rCBV ratios and rMTT ratios of the tumors an contralateral zones were analyzed.Results:Th difference of the maximal rCBV ratios between meningiomas(8.77±6.94),metastasis(5.21±1.91)and gliomas(2.79±1.49)were statistically significant (P<0.01).The angiomatous meningioma was much higher than other types of meningiomas in the maximal rCBV ratio.The rMTT value of the tumors was higher than that of the contralateral zones.However,the rMTT ratios between various tumors showed no statistic difference.Conclusion:Semiquantitative analysis of the maximal rCBV ratio is helpful in the detection of tumor vascularity and extent and may help grading intracranial tumors such as gliomas and making differential diagnosis between extra- and intra-axial tumors.