双源CT肺灌注血池容积成像诊断外周性肺栓塞的价值研究

Diagnostic value of lung perfusion blood volume quantification by dual-energy CT in patients with peripheral pulmonary embolism

目的探讨双源CT肺灌注血池容积(PBV)成像对于外周性肺栓塞的诊断价值。方法对临床诊断肺栓塞的57例患者分别行CT肺动脉造影(CTPA)、肺段PBV成像及肺核素灌注显像(SPECT),所得图像以肺段为评价单位,计算肺段PBV成像灌注兴趣区的平均CT值,CTPA所得的栓塞肺段数、位置,SPECT灌注评分;所得肺段PBV成像结果分别与CTPA及SPECT结果进行相关性分析,对肺段PBV成像平均CT值进行ROC曲线分析。结果存在肺栓塞的肺段PBV成像平均CT值(16.70±3.34)Hu,低于无肺栓塞肺段(28.8±4.62)Hu,差异有统计学意义(t=37.3,P<0.01)。PBV成像平均CT值与CTPA所得的栓塞肺段数呈正相关(r=0.44,P<0.01),PBV成像平均CT值与SPECT肺栓塞灌注评分呈正相关(r=0.72,P<0.01)。ROC曲线分析提示PBV成像定量分析对肺栓塞具有良好的诊断效能,曲线下面积(AUC)为0.932。当PBV成像平均CT值<23.9Hu临界值时,诊断肺栓塞的灵敏度、特异度、阳性预测值、阴性预测值分别为95.5%、86.9%、66.1%、98.6%。结论双源CT肺PBV成像可提高外周性肺栓塞诊断的灵敏度和特异度。

Objective To assess the diagnostic value of lung perfusion blood volume （PBV） quantification by dual-energy CT in patients with peripheral pulmonary embolism （PE）. Methods Fifty seven patients with peripheral pulmonary embolism underwent PBV, CTPA and SPECT. All images were based on subbranches, the number and location of PE in CTPA, Average CT value of PBV in regions of interest and ranking in SPECT were determined. Correlation of lung PBV with CTPA and SPECT were analyzed. Receiver operating characteristic （ROC） curve was used to assess the diagnostic value of PBV in patients with PE. Results There was significant difference in CT value of PBV between patients with and without peripheral PE （t=37.3, P〈0.01）. The average CT value in PBV was significantly correlated with numbers of pulmonary segments with pF shown by CTPA （r=0.44, P〈0.01）. There was a significant correlation between average CT value in PBV and ranking in SPECT with PE （r=0.72, P〈0.01）. ROC analyses demonstrated moderator discriminatory power for using quantification of lung PBV to differentiate patients with and without PE.The area under the curve （AUC） is 0.932.With Hu〈23.9 as the threshold for diagnosis PE, the sensitivity, specificity, positive predictive value and negative predictive value were 95.5%, 86.9%, 66.1%, 98.6%, respectively. Conclusion Quantification of lung perfusion by dual-energy CT can improve the sensitivity and specificity in diagnosis of patients with peripheral pulmonary embolism.