中文摘要：

目的评价磁共振扩散加权成像在鉴别乳腺良恶性病变中的价值。方法对56例乳腺病灶经病理证实的女性患者行磁共振扩散加权成像（magnetic resonance diffusion-weighted imaging MR—DWI），采用2个b值。计算病变的平均ADC（apparent diffusion coefficient）值和相对ADC值，并用统计学软件SPSS13．0进行统计学分析。结果（1）b=500s／mm^2时，恶性病变和良性病变平均ADC值分别为（1．02±0．18）×10^-3mm^2／s、（1．61±0．32）×10^-3mm^2／s；b=1000s／mm^2时，恶性病变和良性病变平均ADC值分别为（0．99±0．16）×10^-3mm^2／s、（1．59±0．33）×10^-3mm^2／s.b=500s／mm^2或1000s／mm^2恶性病变的平均ADC值均明显低于良性病变，且差异均有统计学意义（P=0．001〈0．05）。（2）2个不同b值组ADC值之间差异有统计学意义（t=4．29，P=0．001〈0．05）。（3）以恶性病变平均值95％参考值范围上限界值作为恶性病变上限阈值点，ADC值（b=500s／mm^2和b=1000s／mm^2）及相对ADC值（b=500s／mm^2和b=1000s／mm^2）的阈值点分别为1．32×10^-3mm^2／s、1．25×10^-3mm^2／s、0．81、0．78，取这些阈值点作为乳腺恶性病变的诊断指标，此4种方法诊断乳腺良恶性病变的灵敏度分别为87．5％（28／32）、90．6％（29／32）、90．0％（27／30）、93．3％（28／30），特异度均为91．7％（22／24），正确诊断指数分别为79．2％、82．3％、81．7％、85．0％。结论ADC值是一项磁共振检查鉴别乳腺良恶性病变的可靠指标，相对rADC值为鉴别乳腺良恶性病变提供另一有潜在价值的参数。

英文摘要：

Objective To evaluate the value of diffusion - weighted imaging in distinguishing the benign and malignant breast lesions. Methods fifty - six female patients with pathologically proven breast lesions underwent MR diffusion - weighted imaging（ MR - DWI） using 2 h values. The mean apparent diffusion coefficient（ ADC ） values and the relative ADC （rADC ） values of lesions were measured and analyzed statistically by SPSS 13.0 . Results （1 ） The mean ADC values of the malignant lesions and the benign lesions were （ 1.02 ±0. 18 ）×10^-3mm^2/s and （ 1.61 ±0.32）×10^-3mm^2/s with b =500 s/mm2, （0.99 ±0.16）×10^-3mm^2/s and{ 1.59 ±0.33） ×10^-3mm^2/s with b = 1000 s/mm2 ,respectively. The mean ADC values of breast malignant lesions were lower significantly than that of the benign, and had statistical significance （ P = 0. 001 〈0. 05 ）. （ 2 ） The difference between the ADC values using different b values was of statistical significance（ t = 4.29 ,P = 0. 001 〈 0.05 ）. （ 3 ） The one - side upper limits of 95 % medical reference value of mean values of the malignant lesions were adopted as the threshold point to distinguish the malignant from the benign. The threshold point of the ADC values with b = 500 or 1000 s/ mm2 and the relative ADC values with b = 500 or 1000 s/mm2 were 1.32 ×10^-3mm^2/s, 1.25×10^-3mm^2/s,0. 81 and 0. 78 respectively. The sensitivity of these four thresholds as the indexes in diagnosing breast malignant lesions was 87.5% （28/32） ,90.6% （29/32） ,90.0% （27/30） and 93.3% {28/30） , respectively , the specificity was 91.7% of all , and the Yourdon＇ s indexes were 79.2% ,82.3% ,81.7% , 85.0% respectively. Conclusion The ADC value is a reliable index in distinguishing breast benign lesions from malignant ones. The relative ADC values will provide another potential parameter in differentiating breast benign and malignant lesions.