双源CT双能量肺灌注成像诊断急性肺栓塞的实验研究

目的 评价双源CT(DSCT)双能量肺灌注成像(DEPI)的可行件及其诊断急性实验性肺栓塞的价值.方法 对8只新两兰白兔制备成急性肺栓塞模型的前、后行DSCT平妇及双能量增强扣描,并进行数据后处理,分别得到CT解剖图像(CTPA)、DEPI及两者融合图像,观察肺动脉内有无栓子,分析栓塞前、后的肺灌注影像表现;进行家兔肺大体病理解剖和镜下观察.计算CTPA、DEPI及融合图像的诊断敏感度、特异度、阳性预测值(PPV)、阴性预测值(NPV).应用Kappa系数评价两种检查结果的一致性.结果 7只兔模型制作成功,1只因肺内导管头影响图像评价而排除;6只兔30个肺时数据可用于分析.病理共发现18个肺叶栓塞阳件,12个阴性.与正常肺组织相比,肺柃塞区域DEPI表现为灌注不良或缺损,CTPA表现为相应肺动脉中断或充盈缺损.CTPA诊断的敏感度、特异度、PPV、NPV分别为66.7%(12/18)、100.0%(12/12)、100.0%(12/12)、66.7%(12/18),与病理结果吻合度一般(Kappa=0.651);DEPI诊断的敏感度、特异度、PPV、NPV分别为88.9%(16/18)、91.7%(11/12)、94.1%(16/17)、84.6%(11/13),与病理结果吻合度较强(Kappa=0.795).融合图像结果与DEPI一致.结论 DSCT的DEPI能够反映兔肺部『『fL流分布情况,对肺栓塞的诊断有较高的敏感度,并与病理结果有较强的一致性.

The experimental study on dual-energy imaging for the diagnosis of acute pulmonary embolism using dual-source CT

Objective To evaluate the feasibility and value of dual-energy perfusion imaging (DEPI) of dual-source CT(DSCT) in the diagnosis of acute experimental pulmonary embolism. Methods Acute pulmonary embolism ( PE ) model was made in 8 New Zealand rabbits, and non-enhanced and enhanced DSCT scans were performed before and after embelization. Postprocessing of image data was made on the workstation, and CT pulmonary angiography ( CTPA ), DEal and fusion images were obtained. The location and number of the emboli were recorded. The rabbits were killed immediately after DSCT scan, the location and number of the lung lobes with pulmonary emboli were evaluated pathologically. Based on the pathological results, the sensitivity, specificity, positive predictive value ( PPV), and negative predictive value (NPV) of CTA, DEal and fusion images for the diagnosis of PE were calculated. Weighted Kappa values were calculated to evaluate the consistency between CTPA and DEal. Results PE model was made successfully in 7 rabbits. Six rabbits with 30 lobes were evaluated with one exception because of the catheter affecting the quality of lung peffusian image. PE was found pathologically in 18 lobar arteries. On DEPI, the region with PE showed low peffusion area comparing with the normal parenchyma and CTPA showed the filling defect within corresponding pulmonary artery or interruption of the artery. The sensitivity, specificity, PPVand NPV of CTPA were 66. 7% (12/18), 100.0% (12/12), 100.0% (12/12) and 66. 7% (12/18), respectively. The Kappa value was 0. 651 indicating moderate correlation with pathology. The sensitivity, specificity, aPv, and NPV of DEal were 88. 9% ( 16/18), 91.7% ( 11/12, 94. 1% (16/17) and 84. 6% ( 11/13 ), respectively. The Kappa value was 0. 795 indicating excellent correlation with pathology. Conclusion Dual-energy lung perfusion imaging of DSCT can display the blood distribution of rabbit's lung and has a high sensitivity for the diagnosis of acute pulmonary embolism.