不同b值下弥散加权成像及表观弥散系数在老年肺部肿瘤的临床研究

目的分析不同b值下弥散加权成像(DWI)与表观弥散系数(ADC)用于老年肺部肿瘤良恶性鉴别诊断的价值。方法采用分层整群抽样回顾性分析的方法,抽取我院2015年7月至2018年12月接诊的肺部肿瘤患者100例为研究对象,全部患者均接受磁共振技术弥散加权成像,分析不同病变性质肿瘤的弥散加权成像表现,对比不同良恶性肿瘤在不同b值下弥散加权成像信号强度分布情况及其对应的ADC值,经受试者操作特征曲线(ROC曲线)计算不同b值下ADC值对应曲线面积。结果100例老年肺部肿瘤患者中,检出良性肿瘤、恶性肿瘤例数分别为51例、49例。不同b值恶性肿瘤低信号占比均低于良性肿瘤,高信号占比均高于良性肿瘤,差异有统计学意义(P<0.05);不同b值下,恶性肿瘤ADC值均低于良性肿瘤,差异有统计学意义(P<0.05);且随着b值的升高,全部肺部肿瘤患者ADC值均呈下降趋势,差异有统计学意义(P<0.05);不同b值下ADC值ROC曲线下对应面积分别为0.884、0.834、0.754,AUC>0.5可作为鉴别诊断肺部肿瘤良恶性的有效指标,且以b值为500s/mm2时所得到的ADC指曲线下面积最大,在ADC值取1.470时,可获得最高诊断效能。结论b值为500s/mm2下的弥散加权成像技术信号强度与表观弥散系数用于老年肺部肿瘤良恶性鉴别诊断有着较高价值,患者整体表观弥散系数值随b值的升高而减小。

Clinical Study on Diffusion Weighted Imaging and Apparent Diffusion Coefficient under Different b Values in Differential Diagnosis of Senile Patients with Lung Tumor

Objective To analyze the value of diffusion weighted imaging(DWI) and apparent diffusion coefficient(ADC) under different b values in differential diagnosis of senile patients with benign or malignant lung tumor. Methods The stratified cluster sampling retrospective analysis method was adopted. 100 patients with lung tumor admitted in the hospital from July 2015 to December 2018 were selected as the research subjects. All the patients underwent DWI of magnetic resonance imaging, and the DWI findings of tumors with different pathological properties were analyzed. The distribution of DWI signal intensity and its corresponding ADC values of different benign and malignant tumors under different b values were compared. The receiver operating characteristic curve(ROC curve) was used to calculate the corresponding curve area of ADC values under different b values. Results Among 100 senile patients with lung cancer, 51 cases of benign tumor and 49 cases of malignant tumor were detected;The low signal ratio of malignant tumors under different b values was lower than that of benign tumors, and the high signal ratio of malignant tumors was higher than that of benign tumors, and the difference was statistically significant(P<0.05). Under different b values, the ADC values of malignant tumors were lower than those of benign tumors, and the difference was statistically significant(P<0.05). With the increase of b value, the ADC values of all lung tumor patients showed a downward trend, the difference was statistically significant(P<0.05). The corresponding areas under the ROC curve of different b values were 0.884, 0.834, 0.754, respectively. AUC>0.5 can be used as an effective index for differential diagnosis of benign or malignant lung tumors. When the b value was 500 s/mm2, the area under the ADC index curve was the largest. When the ADC value was 1.470, the highest diagnostic efficiency can be obtained. Conclusion The signal intensity and ADC of DWI technique with the b value of 500 s/mm2 are of high value for the differential diagnosis of benign and malignant lung tumors. The overall ADC of patients decreases with the increase of b value.