扩散峰度成像鉴别诊断乳腺良恶性病变的价值及联合扩散加权成像的诊断效能

The value of diffusion kurtosis imaging in diagnosing breast lesions and its diagnostic efficacy combined with diffusion weighted imaging

目的 探讨扩散峰度成像（DKI）鉴别诊断乳腺良恶性病变的价值及DKI联合DWI对乳腺良恶性病变的诊断效能.方法 前瞻性收集2016年5月至2017年2月中国医学科学院肿瘤医院临床疑诊为乳腺病变,需行乳腺MRI检查,且最终诊断经手术或穿刺病理结果证实的82例患者（89个病灶）纳入研究.患者均行乳腺常规平扫、DWI、DKI及DCE-MRI扫描,获得病变的ADC值、平均扩散率（MD）、平均扩散峰度值（MK）,并观察病变形态、强化方式及时间-信号强度曲线（TIC）类型.采用独立样本t检验（正态分布数据）或Mann-Whitney U检验（偏态分布数据）比较良恶性病变间DKI、DWI参数的差异;采用χ2检验比较良恶性病变间形态、强化方式及TIC曲线类型的差异,采用ROC评价DKI、DWI参数鉴别诊断乳腺良、恶性病变的效能.结果 乳腺良、恶性病变间的长径、腺体类型差异无统计学意义（P均〉0.05）,病变强化形态和TIC类型差异有统计学意义（P均〈0.05）.恶性病变的ADC值及MD值低于良性病变,MK值高于良性病变,差异均有统计学意义（P均〈0.05）.ADC、MD、MK值中,MD值鉴别诊断的ROC下面积为0.975,高于MK（ROC下面积为0.969）和ADC值（ROC下面积为0.873）,诊断效能最佳.联合应用DKI和DWI参数的诊断效能优于单一参数,其中MD和MK值联合诊断的ROC下面积为0.977.MK＋MD＋ADC和MD＋MK的诊断效能相当,ROC下面积为0.978.结论 DKI参数MD、MK值能够用于乳腺良恶性病变的鉴别诊断,联合应用DKI和DWI参数的诊断效能更佳.

Objective To investigate the diagnostic value of diffusion kurtosis imaging （DKI） and its combination with DWI for differentiating benign and malignant breast lesions. Methods Eighty two patients with clinically suspected breast lesions from May 2016 to February 2017 in the Cancer Hospital of Chinese Academy of Medical Sciences were prospectively enrolled in the study. Mammary MRI was performed in all the all patients （89 lesions）, and the pathology results were confirmed by surgery or biopsies. All of them underwent 3.0 T MR examinations, including conventional fat-suppression imaging, DWI, DKI and dynamic contrast-enhanced MR imaging （DCE-MRI）. The ADC values, mean diffusivity （MD）, and mean diffusion kurtosis （MK） values of lesions were obtained, and the lesion morphology, enhancement patterns, and time-signal intensity curve （TIC） types were observed. Independent-samples t test, Mann-Whitney U test were used for the comparison of DKI and DWI between benign and malignant breast lesions. The characteristics of the lesions, enhancement manners and TIC between benign and malignant lesions were analyzed with χ2 test. ROC was used to evaluate the efficacy of DKI and DWI parameters in the differential diagnosis of benign and malignant breast lesions. Results There was no statistically difference for major axis, fiber types （P〉0.05, respectively）. The shape of enhancement mode and TIC had statistical significance （P〈0.05, respectively）. The ADC and MD values were significantly lower in malignant than in benign lesions.Conversely, MK value was significantly higher in malignant lesions than in benign ones, there was a statistically significant difference between these parameters （P〈0.05, respectively）. Among ADC, MD and MK values, the area under the curve （AUC） of MD for differentiating the benign lesions from the malignancy had the highest diagnosis efficiency （0.975）, which was higher than the AUC of MK （0.969） and ADC （0.873）. Combing the parameters of DWI and DKI, the diagnostic performance was superior to the single parameter. The AUC of the combination of MD and MK was 0.977, and the parameters of DKI combined with ADC-value had a equal diagnosis efficiency for the combination of MD and MK, which the areas under the ROC curve was 0.978. Conclusion The parameters derived from DKI can be used to distinguish benign breast lesions from malignant, and the combination of DKI and DWI could obtain a better diagnostic performance than single parameter.