【摘要】 目的探讨 MR 扩散加权成像（DWI）不同扩散敏感因子（b）值对鉴别乳腺良恶性病变的价值。方法测定83例患者95个乳腺病变在 b 值分别取500、1000、2000 s/mm²时的表观扩散系数（ADC）值和信号强度,以手术后病理结果为金标准,比较同一 b 值时不同乳腺病变、以及不同 b 值时同一种病变平均 ADC 值和信号强度的差异。结果 （1）乳腺病变分为乳腺癌、良性病变和囊肿。各种病变的平均 ADC 值、平均信号强度在不同 b 值时不同,其中乳腺癌在 b=500 s/mm²时分别为1.375±0.378和839.713±360.493（与其他病变比较,F 值分别为16.019、30.409,P 均<0.01）;b=1000 s/mm²时分别为1.176±0.311和459.314±229.609（与其他病变比较,F 值分别为16.578和23.092,P 均<0.01）;b=2000 s/mm²时分别为0.824±0.198和243.825±110.616（与其他病变比较,F 值分别为3.122、23.888,P 值分别<0.05和<0.01）。各种乳腺病变两两比较显示在 b=500和1000 s/mm²时,大部分病变之间平均 ADC 值差异有统计学意义,而在 b=2000 s/mm²时仅在乳腺癌和良性病变间差异有统计学意义。（2）以各 b 值时乳腺癌平均 ADC 95%可信区间的上限作为确定乳腺癌的上限阈值点,取这些阈值点在 b 值=500、1000、2000 s/mm²时确定乳腺癌的诊断指标,敏感性分别为70.92%、70.73%、69.77%,特异性分别为77.19%、75.70%、54.76%,准确性分别为77.12%、74.32%、62.35%。ROC 曲线分析曲线下面积（Az）₅₀₀=0.775±0.046,Az₁₀₀₀=0.780±0.044,P 均<0.01,提示 b 取500和1000 s/mm²时对诊断乳腺癌有统计学意义。而 Az₂₀₀₀=0.620±0.062,P>0.05,提示 b=2000 s/mm²对鉴别乳腺良恶性病变差异无统计学意义。结论 b 值取500和1000 s/mm²的 MR DWI 可以用于鉴别乳腺良恶性病变。更多还原

【Abstract】 Objective To evaluate the b value of diffusion-weighted（DW）MRI in distinguishing between benign and malignant breast lesions.Methods Three diffusion-weighted sequences were implemented with 500,1000 and 2000 s/mm² b values respectively on 95 breast lesions in 83 patients.All lesions were confirmed by pathology.The apparent diffusion coefficient（ADC）values and signal intensity （SI）were recorded and compared in different lesions（breast cancer,benign lesion,cyst and normal beast tissue）with the same b value and the same lesions with the different b values.Results（1）The mean ADC value and SI of breast cancer were 1.375±0.378 and 839.713±360.493 respectively with b= 500 s/mm²,1.176±0.311 and 459.314±229.609 with b=1000 s/mm²,0.824±0.198 and 243.825± 110.616 with b=2000 s/mm².The differences in the mean ADC value were significant between two type lesions（cancer and benign lesion,cancer and cyst,cancer and normal breast tissue）with b values of 500 s/mm² and 1000 s/mm².But the significant differenee was only seen between cancer and benign lesions when b value was 2000 s/mm².（2）The one-side upper limits of 95% confidence interval of mean ADCs were adopted as the point to separate the malignant from the benign lesions,the sensitivity was 70.92%, 70.73% and 69.77%,the specificity was 77.19%,75.70% and 54.76%,the accuracy was 77.12%, 74.32% and 62.35% respectively with b values of 500 s/mm²,1000 s/mm² and 2000 s/mm².The areas under ROC eurves were Az₅₀₀=0.775±0.046（P<0.01）,Az₁₀₀₀=0.780±0.044（P<0.01）and Az₂₀₀₀=0.620±0.062（P>0.05）.Conclusion DWI MRI is useful for the differential diagnosis of breast lesions with b values of 500 s/mm² and 1000 s/mm².更多还原