目的 探讨3.0TMR扩散加权成像 不同b值的信号强度下降率及ADC值对乳腺 非肿块型浸润性导管癌及导管原位癌的 诊断价值。方法 收集东莞市人民医院自 2014年6月至2016年12月经手术病理证实 的非肿块型浸润性导管癌78例，导管原 位癌32例，术前均行3.0T MR DWI扫描， b值取0、500、800s/mm2 ，分别测量不同b 值下乳腺病灶DWI信号强度和b=800s/mm2 时病灶ADC值，计算DWI信号强度下降率 (SIDR)，SIDR=(低b值DWI病灶信号强度－ 高b值DWI病灶信号强度)/低b值DWI病灶信 号强度)。对所获得的资料采用两独立样 本t检验进行统计学分析。结果 (1)b=0、 500、800s/mm2 ，乳腺非肿块型浸润性导 管癌及导管原位癌两组间DWI信号强度值 均无统计学意义(P＞0.05)；(2)0-500、 500-800s/mm2 两组b值间乳腺非肿块型浸 润性导管癌及导管原位癌组间SIDR差异 无统计学意义(P＞0.05)；(3)b=800s/ mm2 时，乳腺非肿块型浸润性导管癌及导 管原位癌的ADC值差异有统计学意义(P ＜0.05)。结论 不同b值的信号强度及下 降率对乳腺非肿块型浸润性导管癌及导管 原位癌的鉴别诊断不足以作为参考依据， b=800s/mm2 时ADC值具有参考价值。

Objective To investigate the diagnosis efficiency of decline rate of signal intensity and apparent diffusion coefficient(ADC) with different b values for differentiating breast non-mass invasive ductal carcinoma(IDC) and ductal carcinoma in situ(DCIS) on diffusion-weighted 3.0T magnetic resonance imaging. Methods Collecting 78 cases of non-mass IDC and 32 cases of DCIS from June 2014 to December 2016 in Dongguan People's Hospital. All patients underwent 3.0T magnetic resonance imaging scan before operation, three b values (0,500,800s/mm2 ) were used. The signal intensity with different b value and ADC values with b value(800 s/mm2 )of breast cancers were measured respectively. The signal intensity decline rate(SIDR) was calculated. SIDR=(signal intensity of lesions with low b value- signal intensity of lesions with high b value)/ signal intensity of lesions with low b value. The independent sample t-test was employed for statistical analyses. Results (1) Non significant differences were observed in signal intensity between breast non-mass IDC and DCIS with b values of 0,500,800s/mm2 (P>0.05); (2) Non significant differences were observed in SIDR between breast non-mass IDC and DCIS with b values of 0-500,500-800s/mm2 (P>0.05); (3) Significant difference was observed in ADC value between breast non-mass IDC and DCIS with b values of 800s/ mm2 (P<0.05). Conclusion The signal intensity and decline rate with different b values may be not used for differentiating breast non-mass IDC and DCIS now; ADC value has some reference value with b value of 800s/mm2 .