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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。
Objective: To evaluate the value of perfusion-weighted magnetic resonance imaging (PWI) in the diagnosis of intracranial tumors. Methods: Fifty cases of intracranial tumors were treated with Gd DTPA, and the relative cerebral blood volume (rCBV) was reconstructed from the signal intensity time curve obtained from PWI. Time (rMTT) maps were calculated for each tumor and contralateral normal white matter maximum rCBV ratio and rMTT ratio. Results: The mean rCBV ratios of meningiomas, metastases and gliomas were 8 77 ± 6 94, 521 ± 1 91 and 2 79 ± 1 49, respectively (P <0.01 ). The highest incidence of hemangiomas was found in meningioma, which was significantly higher than other subtypes (P <0.05). The ratio of rCBV in grade Ⅲ ~ Ⅳ glioma was significantly higher than that in grade Ⅰ ~ Ⅱ (P <0.01). Each tumor rMTT ratio than the contralateral normal white matter increased. There was no significant difference in rMTT ratio between different tumors. Conclusion: The semi-quantitative study of rCBV ratio is helpful to observe the blood supply and the exact range of tumor tissue. It is of great value in differentiating malignant glioma and differentiating intracerebral and intracranial tumors.