弥散加权图像在鉴别脑脓肿与坏死、囊变脑肿瘤中的作用

Role of diffusion weighted imaging in distinguishing between brain abscess and necrotic or cystic tumor

目的 评价弥散加权图像在鉴别脑脓肿和坏死、囊变肿瘤中的作用。方法 对连续5例脑脓肿、7例恶性脑肿瘤和 1例脑转移瘤进行常规MRI和弥散加权成像 ,取扩散敏感系数 (b值 ) :b =0 ,b =1 0 0 0或b =0 ,b =1 2 0 0 ,测量病变感兴趣区的表观弥散系数 (ADC) ,行 2个独立样本秩和检验。结果 所有脑脓肿在弥散加权图像上均呈高信号 ,而所有脑肿瘤坏死、囊变部分均呈低信号。脓腔内的平均ADC值为 0 .43× 1 0 - 3cm2 /s ,明显低于肿瘤坏死、囊变部分的平均ADC值 1 .89× 1 0 - 3cm2 /s(T =1 5.0 0 ,P <0 .0 1 )。结论 弥散加权成像可以用来鉴别脑脓肿和坏死、囊变肿瘤。

Objective To evaluate the role of diffusion weighted (DW) echo planar MRI in differentiating between brain abscesses and necrotic or cystic tumors. Methods Five patients with brain abscesses, 7 with malignant gliomas, and 1 with brain metastasis were consecutively examined using conventional MRI and diffusion weighted imaging (DWI). The apparent diffusion coefficient (ADC) of ROI was measured with two different b values (0 and 1 000 s/mm 2 or 0 and 1 200 s/mm 2). The results were analyzed using two independent samples test. Results On diffusion weighted imaging, brain abscesses showed marked hyperintensity in all 5 patients, whereas necrotic or cystic brain tumors demonstrated hypointensity in all 8 patients. ADC mean values of brain abscesses, which was 0.43×10 -3 cm 2/s, were lower than those of necrotic or cystic portion of brain tumors ( T =15.00, P <0.01). Conclusion DW echo planar MRI can be used to distinguish between brain abscesses and necrotic or cystic tumors.