功能MRI在乳腺疾病中的应用

Application of functional MRI in breast diseases

目的研究功能 MR 成像(fMRI)在乳腺疾病诊断与鉴别诊断中的价值。方法对65例患者共计68个病灶进行 fMRI 检查,所有病例均经手术病理证实。扫描序列包括 T_1WI 与 T_2WI平扫、动态增强、扩散加权成像(DWI)与单体素~1H 波谱分析。分析病灶的形态学特征;根据动态增强绘制时间-信号曲线,计算最大强化率;根据扩散加权统计表观扩散系数(ADC);当发现病灶时进行波谱分析,并将胆碱峰视为乳癌阳性发现。结果 T_1WI 与 T_2WI 的病灶检出率分别为14.7%(10个)与51.5%(35个)。而动态增强序列对恶性肿瘤的敏感性为94.6%(35/37),特异性为71.4%(35/49),诊断正确率为76.5%(52/68)。回顾性研究表明,扩散敏感因子(b)值为800～1000 s/mm^2时,DWI 能够很好地鉴别各类病灶。单体素质子波谱分析的敏感性为51.4%(19/37),特异性为82.6%(19/23),诊断正确率为67.6%(46/68)。MR 平扫、动态增强与 MRS 相结合的联合诊断对乳腺恶性肿瘤的敏感性为97.3%(36/37),特异性为90.0%(36/40),诊断正确率为92.6%(63/68)。结论 fMRI 对乳腺恶性肿瘤的敏感性、特异性与诊断正确率均较高,有着广阔的应用前景。

Objective To investigate the value of functional MRI in the diagnosis and differential diagnosis of breast diseases. Methods Sixty-five patients with 68 lesions were enrolled in this study. Conventional T1WI and T2WI scan, dynamic contrast enhanced MRI, diffusion weighted imaging and ^1H single voxel MR spectroscopy were performed consequently. All lesions were verified by pathology, including 4 cases of breast adenosis, 22 fibroadenomas, 2 chronic inflammations, 3 cysts, 33 infitrating ductal carcinomas, 1 intraductal carcinoma and 3 cystosarcoma phyllodes tumors. Morphological features, maximum enhancement ratio, time-intensity curve, apparent diffusion coefficient and Choline peak were analyzed. Results The detection rates of T1WI and T2WI were 14.7% （ n = 10） and 51.5% （ n = 35 ）. The sensitivity, specificity, accuracy of dynamic contrast enhanced MRI for the malignant tumor were 94. 6%, 71.4% and 76. 5% respectively. Retrospective study showed that diffusion weighted imaging, with the b value from 800 s/mm^2 to 1000 s/mm^2 , could be used to differentiate various types of breast lesions. ^1H signal voxel spectroscopy had a sensitivity of 51.4%, specificity of 82. 6%, and accuracy of 67.6% for the malignent. The sensitivity, specificity and accuracy could reach 97.3%, 90. 0% and 92.6% respectively by combining conventional scan, dynamic contrast enhanced MRI and MR spectroscopy. Conclusion Functional MRI, with high sensitivity, specificity and accuracy, can be used widely in the diagnosis of malignant breast lesions.