乳腺MRI多b值下ADC值定量对腋窝淋巴结定性诊断价值及b值优化

目的：评价ADC值定量对腋窝淋巴结的定性诊断价值并探讨b值的优化选择。材料与方法搜集在我院进行乳腺磁共振扩散加权成像（DWI）及动态增强扫描患者，DWI扫描选取3组b值（0、400 s/mm2，0、800 s/mm2，0、1000 s/mm2）分别进行扫描；对有明确手术病理结果和（或）针吸活检病理结果的59例患者共96枚腋窝淋巴结进行回顾性分析。结果3组b值下恶性淋巴结的ADC值明显低于良性淋巴结，有显著统计学差异（P=0.000），b=400 s/mm2时，以1.24×10-3mm2/s为阈值，诊断良恶性病变的敏感性、特异性分别是88.53%、62.85%；b=800 s/mm2时，以0.955×10-3mm2/s为阈值，分别为77.14%、78.69%；b=1000 s/mm2时，以0.890×10-3mm2/s 为阈值，分别是77.14%、81.97%。3组b值ROC曲线下面积分别为0.828，0.849，0.873。结论 ADC值对腋窝良恶性淋巴结具有较高的鉴别诊断价值。当b=1000 s/mm2时，ADC值定量诊断效能最高。

The apparent diffusion coefifcient measurement in diagnosis of axillary lymph node lesions with multi b values and optimizing b value

Objective： To compare apparent diffusion coefficient measurement of benign axillary lymph node and malignant axillary lymph node identification value and optimizing b value. Materials and Methods：By collecting in the hospital for breast dynamic contrast-enhanced scans and diffusion-weighted imaging,using three b values （400, 800, 1000 s/mm2）. 59 patients （96 lymph nodes） with a clear outcome of the surgery and pathology and/or needle biopsy results were retrospectively analyzed. Results：The ADC values of malignant lesions were signifi cantly lower than those of benign lesions（P=0.00）.The sensitivity and specificity were 88.53%and 62.85%, 77.14% and 78.69%, 77.14% and 81.97% respectively when b=400, 800 and 1000 by using a threshold ADC of less than 1.240, 0.955, 0.890×10-3mm2/s respectively. Areas under the curve are 0.828, 0.849, 0.873 as b=400 s/mm2, 800 s/mm2, 1000 s/mm2, respectively. Conclusions：The ADC value has moderate diagnosis potency in differentiating benign and malignant lymph node. The optimal b value is 1000 s/mm2.