磁共振体素内不相干运动扩散加权成像在肺癌所致肺不张影像诊断中的初步应用

目的:探讨磁共振体素内不相干运动扩散加权成像(intravoxel incoherent motion diffusion weighted MR Imaging,IVIM-DWI)在肺癌所致肺不张的影像诊断中的初步应用。方法:选取独立肺段肺不张病变患者43例,其中肺癌致肺不张31例(肺癌组),局部炎症致肺不张12例(炎症组)。所有患者在药物治疗或手术前均行3.0T磁共振IVIM-DWI检查,b值取0、50、100、200、400、600、800、1000 s/mm~2,分别测量灌注分数(perfusion fraction,f)、真实扩散系数(diffusion coefficient,D)以及关注相关扩散系数(diffusion coefficient from the perfused compartment,D*),对上述参数值进行相关统计学分析,并依据受试者工作特征曲线(Receiver Operating Characteristic,ROC)对各参数的评价效能进行分析。结果:肺癌组的D值、D*值以及f值分别为(0.64±0.16)×10~(-3)mm~2/s、(19.77±6.16)×10~(-3)mm~2/s以及(29.62±9.74)%,而炎症组的D值、D*值以及f值分别为(0.67±0.14)×10~(-3) mm~2/s、(21.14±8.32)×10~(-3)mm~2/s以及(47.62±11.46)%;经比较,肺癌组D值、D*值与炎症组无统计学差异(P0.05),而二者f值差异显著,有统计学意义(P0.01)。f值最佳阈值为38.42%,此时曲线下面积(Area Under Curve,AUC)为0.94,诊断肺癌的特异度为0.89,敏感度为0.93,阳性预测值为0.92,阴性预测值为0.89。结论:磁共振IVIM-DWI技术在肺癌所致肺不张的影像诊断中具有一定的应用价值。

Preliminary Study of Intravoxel Incoherent Motion Diffusion Weighted MR Imaging for Differentiation Diagnosis of Lung Cancer fromLobar Collapse

Objective:To investigate the preliminary study of intravoxel incoherent motion diffusion weighted MR imaging (IVIM-DWI) in differentiation diagnosis of lung cancer from lobar collapse.Methods:38 patients (31 cases of central lung cancer, 12 cases of infectious granuloma)with solitary pulmonary lesions were selected. All cases were examined with IVIM-DWI sequence before operation or medication. b-values was0, 25, 50,7 5,100, 200,400, 600, 800, 1000 s/mm2 respectively. The parameters of diffusion coefficient (D), diffusion coefficient from the perfused compartment (D*) and perfusion fraction (f) of all lesions was calculated.The diagnostic efficiency of each parameter of ROC curve is plotted.Results:The D,D* and f value of malignant group was (0.64± 0.16)× 10-3 mm2/s, (19.77± 6.16)× 10-3 mm2/s and (29.62± 9.74)%, And the benign group was (0.67± 0.14)× 10-3 mm2/s, (21.14± 8.32)× 10-3mm2/s and (47.62± 11.46)%respectively. There was no significant difference between malignant group and benign group for D and D*(P>0.05), but the value of f was significantly lower in malignant group comparing with benign group(P<0.01). The cut-off of f values was 38.42%,and the area under the ROC of the f values was 0.94, The specificity,sensitivity, Positive predictive value and Negative predictive value in the diagnosis of lung cancer was 0.89, 0.93, 0.92, 0.89 respectively.Conclusion:The f value of IVIM-DWI is helpful in diagnosis of lung cancer fromlobar collapse.