高场MRI多b值DWI在肺部占位性病变诊断中的应用研究

Application research of multi-b-value DWI in high-field MRI for the diagnosis to lung space-occupying lesions

目的:探讨高场MRI多b值DWI对肺部占位性病变的诊断效能及最佳b值的选择。方法:收集69例经病理或临床证实的肺内占位性病变患者的临床及影像资料,均行MRI胸部常规T1WI、T2WI和多b值DWI检查,b值选取0、300、500、800、1000、1200 s/mm^(2)。测量各b值占位性病变的ADC值,并根据ROC曲线评价不同b值下ADC值对肺良、恶性占位病变的诊断效能,并获得诊断肺部占位性病变的最佳b值。结果:随b值增加,肺部占位性病变的ADC值逐渐降低,b值取300、500、800、1000、1200 s/mm^(2)时,ROC曲线的AUC分别为0.810、0.831、0.897、0.883、0.879,均有诊断意义。当b值取800 s/mm^(2)时,ADC值的诊断效能最大,鉴别诊断肺良、恶性占位性病变的阈值为1.127×10^(-3) mm^(2)/s;当b值取800 s/mm^(2)时,小细胞肺癌的ADC值低于非小细胞肺癌(P<0.05),ADC值的诊断阈值为0.817×10^(-3) mm^(2)/s。结论:1.5 T MRI多b值DWI在肺部占位性病变的诊断中有较高的价值,当b值取800 s/mm^(2)时ADC值的诊断效能最高。

Objective:To explore the diagnostic efficacy of multi-b-value DWI in high-field MRI for lung space-occupying lesions and to find out the best b value. Methods:Clinical and imaging data were collected of 69 patients with pathologically or clinically confirmed lung space-occupying lesions. T1WI,T2WI and multi-b-value DWI were performed for all patients,with b values of 0,300,500,800,1 000 and 1 200 s/mm^(2). ADC values from all b values were measured and evaluated for the diagnosis to benign and malignant lesions using the ROC curve,and the optimal b values were obtained. Results:With the increase of b value,ADC value of lung space-occupying lesions decreased,and AUC of different b values of 0,300,500,800,1 000 and 1 200 s/mm^(2) was 0.810,0.831,0.897,0.883 and 0.879,respectively,all of which had diagnostic significance (AUC>0.5). When the b value was 800 s/mm^(2),the ADC value had the highest diagnostic efficacy for the diagnosis of benign and malignant lesions,and the threshold value was 1.127×10^(-3) mm^(2)/s. The ADC value of small cell lung cancer was lower than that of non-small cell lung cancer,and when b value was 800 s/mm^(2),the diagnostic threshold of ADC value was 0.817×10^(-3) mm^(2)/s. Conclusions:Multi-b-value DWI in 1.5 T MRI has a high value in the diagnosis of lung space-occupying lesions with the highest diagnostic efficacy when b value is 800 s/mm^(2).