中文摘要：

目的研究磁共振扩散加权成像（DWI）对确定乳腺癌肿瘤边界的价值。资料与方法使用Philips 1．5 T磁共振扫描仪及乳腺线圈对33例乳腺癌患者的35处病变行常规T。脂肪抑制序列和sET：常规扫描以及回波平面成像（EPI）DWI扫描。依次测量乳腺癌肿瘤与肿瘤周围组织的表观扩散系数（ADC）值并进行统计学比较。所有病例均经病理证实。结果35处病变中，3处为导管原位癌，31处为非特异性浸润性导管癌，1处为乳腺肉瘤。乳腺癌的ADC值显著低于肿瘤周围组织的ADC值。对于乳腺癌肿瘤的周围组织，在矢状位的ADC图上，同一层面的不同方向（前，后，上，下）的ADC值之间差异无统计学意义（P=0．534，0．986．0．895均〉0．05）。但对于同一方向上的不同层面，靠近肿瘤的第一层ADC值小于远离它的3个层面（P=0．009〈0．05）。结论ADC值对判别乳腺癌组织与癌周组织有一定的敏感性和特异性；采用EPI-DWI方法检测乳腺癌周围组织ADC值的变化，有望成为帮助确定乳腺癌手术边界的一种有效的影像学方法。

英文摘要：

Objective To evaluate tumor margin by diffusion-weighted imaging in breast cancer. Materials and Methods MRI was performed in 33 patients （35 lesions） with a Pbilips 1.5 T MR system and a dedicated phased-array bilateral breast coil. The imaging protocols included a fat-suppressed T1 -weighted sagittal scan and a SE T2-weighted transverse and Gradient echo planar image DWI pulse sequence. The ADC values of the tumor tissue and peri-tumor tissue in breast cancer were measured and analyzed statistically. All the cases were confirmed by pathology. Results The histological types of 35 lesions were as follow： ductal carcinoma in situ （n=3） , non-specific invasive carcinoma （n=31 ） , and breast sarcoma （n=1 ）. The ADC value in the tissue of breast cancer was significantly lower than that of the peri-tumor tissue. In the ADC map of sagittal scan, there was no statistically different in ADC values among different directions （ anterior, posterior, upper and lower） within same slice （P = 0. 534,0. 986,0. 895, all〉0.05 ）. However, there was statistically different in the ADC value among different slices within same direction and the ADC value in the tissue of the first slice adjacent to tumor was lower than that of other three slices away from tumor （P=0.009 〈0.05 ）. Conclusion ADC value was a sensitive and specific parameter that could help to differentiate malignant breast lesions and normal tissue in peritumor. ADC value changes in tissues adjacent to breast carcinoma could be detected by EPI-DWI, which made EPI-DWI a promising method for helping to determine surgical scope of breast carcinoma.