不同b值下的ADC值对肺部病变诊断的价值

目的:评价不同b值下的ADC值在肺良恶性占位性病变诊断中的应用价值。方法:70例患者行不同b值(分别为0、500、700、900s/mm2)的DWI扫描,对70个病灶进行分析,全部病灶依据术后病理或穿刺活检病理为标准,对所获资料采用两独立样本t检验进行统计学分析。结果:b值为500、700、900s/mm2时,良性组与恶性组之间ADC值的差异均有统计学意义(P<0.01)。以恶性组ADC值95%可信区间上限作为诊断阈值,则b值为500、700、900s/mm2时,诊断阈值分别为1.687×10-3 mm2/s、1.465×10-3 mm2/s、1.543×10-3 mm2/s。应用ROC曲线分析不同b值时ADC阈值诊断恶性病变的作用,显示b值为700s/mm2时价值最大,其诊断敏感度、特异度、准确性、阳性和阴性预测值分别为92.86%、76.92%、82.50%、93.57%和66.67%。结论:b值为700s/mm2时获得的ADC值效能较高。

Different b value on ADC in diagnosis of lung cancer

Objective： To evaluate the application of ADC value using different b value in the diagnosis of pulmonary benign and malignant mass. Methods.. 70 patients with chest MRI DWI scan using different b value （0,500,700,900 s/ mm2 ）. 70 lesions were analyzed based on the postoperative pathological or puncture biopsy of all lesions as standard,and two independent samples t test was used for statistical analysis of the information obtained. Results： The AIDC value differences were statistically signifi- cant between benign group and malignant group with the b value of 500 s/mm^2 , 700 s/mm^2 , 900 s/mm^2 （ P 〈0.01）. Taking upper limit of 95% confidence interval of ADC value in the malignant group as a diagnostic threshold, the diagnostic threshold was 1. 687×10^-3mm^2/s, 1. 465 ×10^-3mm^2/s, 1. 543×10^-3mm^2/s with b value of 500 s/mm2 , 700 s/ram2 , 900 s/mm2 , respective ly. Using ROC curve to analyze ADC threshold role in the diagnosis of malignant lesions in different b value, b value of 700 s/ mma had maximum value when the diagnostic sensitivity, specificity, coincidence rate, positive and negative predictive values were 92.86%, 76.92%, 82.50%, 93.57% and 66, 67%, respectively. Conclusion： The optimal b value is 700 s/mm2.