自旋回波与翻转恢复T1 WI在原发性脑肿瘤诊断中的比较

T_1 Weighted Imaging in Diagnosis of Primary Brain Tumors:Spin Echo vs Inversion Recovery

目的:通过SET1WI与T1FLAIR的比较研究,探讨原发性脑肿瘤MRI的最佳T1WI序列。方法:77例原发性脑肿瘤患者行增强前后SET1WI和T1FLAIR,比较两序列增强图像上肿瘤的边界和肿瘤体积,计算肿瘤与白质、灰质及脑脊液的对比率(CR)和对比噪声比(CNR)。计算并比较两序列上灰质与白质的CR和CNR。结果:增强前T1FLAIR具有更高的CR和CNR,增强后肿瘤与白质、肿瘤与灰质的CR在SET1WI序列上更高,而增强后的3种CNR和肿瘤与脑脊液的CR则在T1FLAIR上更高。在肿瘤边界的显示中,增强前T1FLAIR在46例中更优,31例两序列相似;增强后SET1WI在16例中优于,61例两序列相似。两序列增强图像上测得的肿瘤体积无显著差异。增强前后T1FLAIR上白质与灰质的CR和CNR均高于SET1WI。结论:SE是原发性脑肿瘤增强T1WI的首选序列,T1FLAIR可作为替代序列。

Objective：To determine the optimal sequence of T1 weighted imaging in primary brain tumors by compa ring results of spin echo （T1 WISE） with inversion recovery （T1 WIR）. Methods： Seventy eight patients with primary brain tumors were subjected to T1 WI SE and T1 W IR before and after enhancement. T1 WISE and T1 WI IR images were compared for boundary,volume,enhanced degree and contrast-to enhancement ratio （CER） of tumors, contrast ratio （CR） and contrast to-noise ratio （CNR） of tumor-to white matter （T/WM）, tumor-to grey matter （T/GM） and tumor-toCSF （T/CSF）. Results：The enhanced degree of tumors was greater on T1 WI IR than on T1 WI SE,but the CER of tumors was higher on T1 WISE. Before enhancement, the CR and CNR of T/WM, T/GM and T/CSF were higher on T1WI IR;after enhancement,CR of T/WM and T/GM was higher on T, WI SE,but CR of T/CSF and CNR of T/WM,T/GM and T/CSF were higher on T1WI IR. In delineation of tumor boundaries,T1WI IR images were superior in 46 patients and fair in 32 patients to T1 WISE before enhancement;but after enhancement,T1WI SE images were superior in 16 patients and fair in 62 patients to T1 WI IR. Tumor volume was （25.0±21.4） and （25.0±21.5）cma respectively on T1 WISE and T1 WI IR ima ges after enhancement with the difference being not significant. CR and CNR of white matter to grey matter were higher on T1 WI IR than on T1 WISE pre- and post-enhancement. Conclusion：SE is the first selected sequence of enhanced T1 weighted imaging in primary brain tumors,and T1 WI IR can be employed as substitute.