肝脏局灶性小病灶MRI定量指标与病灶性质的相关研究

目的　探讨T1、T2 值及T2 指数 (T2 index)在区分肝脏局灶性小占位性质方面的价值。资料与方法　随机选择经确诊的肝细胞癌、肝转移瘤、肝海绵状血管瘤和肝囊肿患者共 92例 (14 8个病灶 ) ,行前瞻性MRI(0 .5T)研究 ,计算病变的T1、T2 值及T2 指数 ,并进行统计学分析。结果　恶性病变的T1值显著低于良性病变 (t =4 .0 2 4 ,P <0 .0 0 1) ,但由于数值重叠较多 ,对诊断无实际应用价值 ;良性病变的T2 值显著高于恶性病变 (t =10 .92 9,P <0 .0 0 1) ,第一个双回波 (TR 2 5 0 0ms,TE 30、90ms)以 84ms为界区分良、恶性病变 ,诊断正确率为 92 %。第二个双回波 (TR 2 5 0 0ms,TE 6 0、12 0ms)以 80ms为界 ,诊断正确率为 93% ;良性病变的T2 指数均显著高于恶性肿瘤 (t =13.6 97,P <0 .0 0 1) ,TE 30、90ms时 ,以 1.89为界 ,诊断正确率为 92 % ,TE 6 0、12 0ms时 ,以 2 .0 1为界 ,诊断正确率亦为92 %。结论　T2 值和T2 指数在区分肝脏良、恶性占位性病变方面有肯定的价值

MRI of Small Focal Hepatic Lesions: Correlation betweenQuantitative Indexes and Lesion''s Nature

Objective To evaluate T 1 value, T 2 value and T 2 index in judging the nature of small focal hepatic lesions.Materials and Methods Ninety two patients with total 148 pathologically confirmed focal hepatic lesions, including hepatocellular carcinoma, hepatic metastasis, cavernous hemangioma or cyst, were randomly selected. Prospective MRI on a 0.5T unit using spin echo sequences was performed. T 1 and T 2 relaxation time, and T 2 index of the lesions were measured individually.Results T 1 relaxation time of malignant lesions was significantly shorter than that of benign lesions (t=4.024, P<0.001), but it had no practical value in making diagnosis as a large number of T 1 value in the two groups was overlapped with each other. T 2 relaxation time of benign lesions was significantly longer than that of malignant lesions (t=10.929, P<0.001). The accuracy of differentiating benign with malignant lesions at the first double echo sequence was 92% when 84 msec of T 2 relaxation time was used as the criteria, while the accuracy was 93% at the second double echo sequence when 80 msec was used. T 2 indexes of the benign lesions were significantly higher than that of malignant ones (t=13.697, P<0.001). The accuracy of classifying lesions as benign or malignant was 92% when TE=30 or 90 msec and 1.89 was used as the dividing line, or when TE=60 or 120 msec and 2.01 was used as the dividing line.Conclusion Both T 2 relaxation time and T 2 indexes are surely of value in differentiating malignant hepatic lesions from benign ones.