磁共振扩散加权成像及动态增强MRI在乳腺病变中的应用价值

The value of magnetic resonance diffusion weighted imaging and dynamic contrast-enhanced MRI in the diagnosis of benign and malignant breast lesions

目的探讨月经周期对正常乳腺实质磁共振扩散加权成像（DWI）表观扩散系数（ADC）值的影响，并评价动态增强MRI（DCE—MRI）及DWI在乳腺病变鉴别诊断中的价值。方法选取健康女性志愿者34例、乳腺病变患者96例，所有病例均经外科手术或针吸病理证实，其中良性病变者36例，共44个病灶；恶性病变者60例，共70个病灶。对34例健康志愿者分别于其月经周期的第1、2、3、4周行T1加权MRI、T2加权MRI及DWI。对96例乳腺病变患者的114个病灶分别于术前行T1加权MRI、T2加权MRI、液体衰减反转序列MRI、DCE-MRI及DWI。结果①正常乳腺的ADC值在月经周期的第2周降至最低，后缓慢升高，各周均值之间比较的差异无统计学意义（F=1．029，P〉0．05）。②在DCE-MRI的诊断中，III型曲线是典型乳腺癌的影像表现，I型和IV型曲线对诊断乳腺良性病变有意义。③当b值为1000S／mm^2时，良恶性乳腺病变的ADC诊断阈值是1．25×10^-3mm2／s。结论在乳腺DWI中，月经周期对正常乳腺实质的ADC值影响较小。DCE-MRI和DWI对乳腺良恶性病变的诊断和鉴别诊断具有重要价值。

Objective To explore the relationship between the menstrual cycle and apparent diffusion coeffieient（ADC） values of MR diffusion weighted imaging（DWI）. To investigate the evaluation of DWI and dynamic contrast-enhanced MRI（DCE-MRI） in distinguishing benign from malignant breast lesions. Methods Thirty-four healthy, premenopausal female volunteers who had regular menstrual cycles and 96 breast disease patients who proved by surgery or Needle aspiration pathology were included in the study. Of the 96 patients, there were 36 cases with 44 benign breast lesions and 60 cases with 70 malignant breast lesions. The healthy volunteers were scanned by conventional T1 weighted MRI, T2 weighted MRI and DWI once a week for 4 weeks with Siemens Sonata 1.5T MRI（b=1000s/mm2 ）. The patients were examined by conven- tional MRI, DCE-MRI and DWI. DWI using Echo planar imaging technique and frequency selection suppression technology were used in DWI（b=1000 s/mm2）and fast low angle shot sequence was used in DCE-MRI. The data of DWI and DCE-MRI were sent to Leonardo workstation. Results ①ADC values of normal breast in the second week of the menstrual cycle reduced to minimum and then slowly increased, a comparison between the mean was not significant （F=1.029, P〉0.05）. ② In DCE-MRI, type III curve is the typical type of breast cancer, type I and IV curve are the typical type of breast benign lesions. ③When b=1000 s/mm2, the diagnostic threshold of ADC values between the benign breast lesions and malignant lesions was 1.25×10^-3 mm2/s. Conclusions ADC values were less influenced by the menstrual cycle in normal breasts. The specificity and accuracy in the diagnosis of benign and maglinant breast lesions were improved with the combination of DCEMRI and DWI.