3.0TMR扩散加权成像不同b值的信号强度及ADC值下降率对乳腺良恶性病变的诊断价值

Diagnostic efficiency of decline rate of signal intensity and apparent diffusion coefficient with different b values for differentiating benign and malignant breast lesions on diffusion-weighted 3.0T magnetic resonance imaging

目的：探讨3.0 T MR扩散加权成像不同b值的信号强度及ADC值下降率对乳腺良恶性病变的诊断价值。方法对东南大学附属中大医院自2010年12月至2012年12月经手术病理证实的152例162个乳腺病灶（恶性85灶，良性77灶）行3.0 T MR DWI扫描，b值取0、400、800、1000 s/mm2，分别测量不同b值下乳腺病灶DWI信号强度及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病灶信号强度及ADC值下降率（ ADCDR），ADCDR＝（低b值病灶ADC值-高b值病灶ADC值）/低b值病灶ADC值）。对所获得的资料采用两独立样本t检验进行统计学分析并采用ROC曲线评价SIDR值及ADCDR值的诊断效能。结果（1）0～400、400～800和800～1000 s/mm23组b值间良、恶性病灶SIDR差异均有统计学意义（均P＜0.01）。（2）3组b值间的SIDR对良恶性病变诊断的敏感性分别为61.2％、68.2％和67.1％，特异性分别为74.0％、85.7％和67.5％；诊断符合率分别为67.3％、76.5％和67.3％；阳性预测值分别为72.2％、84.1％和69.5％；阴性预测值分别为63.3％、71.0％和65.0％。（3）400～800、800～1000 s/mm2两组 b值间良、恶性病灶ADCDR差异均有统计学意义（均P＜0.01）。（4）两组b值间的ADCDR对良恶性病变诊断的敏感性分别为80.0％、65.9％，特异性分别为72.7％、65.0％；诊断符合率分别为76.5％、65.4％；阳性预测值分别为76.4％、67.5％；阴性预测值分别为76.7％、63.3％。结论不同b值的信号强度下降率及ADC值下降率对乳腺良恶病灶都具有鉴别诊断价值，且诊断效能以400～800 s/mm2间为最佳。

Objective To investigate the diagnostic efficiency of decline rate of signal intensity and apparent diffusion coefficient with different b values for differentiating benign and malignant breast lesions on diffusion-weighted 3.0T magnetic resonance imaging.Methods A total of 152 patients with 162 confirmed histopathologically breast lesions （85 malignant and 77 benign） underwent 3.0T diffusion-weighted magnetic resonance imaging.Four b values （0, 400, 800 and 1 000 s/mm2 ） were used.The signal intensity and ADC values of breast lesions were measured respectively.The signal intensity decline rate （ SIDR ） and apparent diffusion coefficient decline rate （ ADCDR） were calculated respectively.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, ADCDR =（ ADC value of lesions with low b value-ADC value of lesions with high b value ）/ADC value of lesions with low b value.The independent sample t-test was employed for statistical analyses and the receiver operating characteristic （ ROC） curve for evaluating the diagnosis efficiency of SIDR and ADCDR values.Results Significant differences were observed in SIDR between benign and malignant breast lesions with b values of 0-400, 400-800 and 800 -1 000 s/mm2.The sensitivities of SIDR for differentiating benign and malignant breast lesions were 61.2%, 68.2% and 67.1%, the specificities 74.0%, 85.7%and 67.5%, the diagnosis accordance rates 67.3%, 76.5% and 67.3%, the positive predictive values 72.2%, 84.1%and 69.5%and the negative predictive values 63.3%, 71.0%and 65.0% respectively.Significant differences were observed in ADCDR between benign and malignant breast lesions with b values of＆amp;nbsp;400-800 s/mm2 and 800-1 000 s/mm2.The sensitivities of SDR for differentiating benign and malignant breast lesions were 80.0% and 65.9%, the specificities 72.7% and 65.0%, the diagnostic accordance rates 76.5% and 65.4%, the positive predictive values 76.4% and 67.5% and the negative predictive values 76.7% and 63.3% respectively.Conclusion The decline rate of signal intensity and apparent diffusion coefficient with different b values may be used for differentiating benign and malignant breast lesions.And the diagnostic efficiency with b values of 400-800 s/mm2 is optimal.