低剂量对比剂双能量肺灌注成像评估肺动脉内血栓与灌注缺损间的关系

摘要

目的:应用双源CT低剂量对比剂双能量肺灌注成像评估急性肺动脉栓塞患者血管内血栓与肺灌注缺损间的关系,以提高对肺动脉栓塞诊断的准确性.方法:随机选择无肺动脉栓塞患者的低剂量与常规剂量双能量肺灌注成像各15例,对比分析其图像质量；收集20例疑肺动脉栓塞患者行低剂量双能量肺灌注成像；同时获得肺动脉CTA及肺灌注图像.分析肺动脉内有无血栓.以及血栓的部位、数量及形态特征.用双能量肺灌注分析软件判断有无灌注缺损及缺损的部位、形态及范围.对比分析并统计肺动脉内血栓与肺灌注缺损间的关系.结果:肺动脉栓塞患者的低剂量与常规剂量双能量肺灌注成像质量无明显差异(P＞0.05).20例疑似病例中,15例诊断为肺动脉栓塞,其中13例患者肺灌注图像中出现102个肺叶、肺段、或亚段灌注缺损,4例共6个灌注缺损CTA无明确血栓；11例肺动脉CTA显示43个血栓,其中9例血栓与灌注缺损同时存在,2例CTA共5个血栓肺内无灌注缺损.75个灌注缺损与栓塞肺动脉供血范围一致,21个灌注缺损(8段、13亚段)与肺动脉供血范围无关.结论:综合分析双源CT低剂量双能量肺灌注图与CTPA,可以提高肺动脉栓塞诊断的准确性.%Objective: To assess the relation between intravascular clots of pulmonary artery and lung perfusion defects with dual source CT low-dose contrast perfusion imaging so as to elevate the accuracy of diagnosis of PE. Methods: The image quality of low-dose and conventional dose dual energy lung perfusion imaging (DEPI) of patients without pulmonary embolism (PE). With 15 cases in each sose, were analyzed. Twenty consecutive patients with suspected PE underwent dual source CT low-dose contrast perfusion imaging and CT pulmonary angiography (CTPA) and lung perfusion images were aquired at the same time. The intravascular clots of pulmonary artery if or not, including the clots location, number and morphology, were analyzed by the axial image and three-dimensional reconstruction of CTPA. Lung perfusion defects and its location, extent were evaluated with lung PBV software on the workstation. The relationship between intravascular clots of pulmonary artery and lung perfusion defects were statistically analyzed. Results:The image quality of low-dose and conventional dose DEPI of patients without PE had no significant difference ( P >0. 05). PE was diagnosed in 15 patients. 13 patients were found 102 perfusion defects by pulmonary perfusion imaging, including lobes, segmental and subsegmen-tal perfusion defects. 6 perfusion defects of 4 cases had no clear intravascular clots. Images of axial CTPA and three-dimensional reconstruction showed 43 intravascular clots in 11 patients. Two cases of 5 intravascular clots depicted by CTPA showing no perfusion defects. 9 cases were simultaneously appeared intravascular clots and perfusion defects, which had 21 perfusion defects unrelated to the blood supply areas of pulmonary artery (8 segments, 13 subsegments). The remaining 75 perfusion defects were consistent with the blood supply areas of pulmonary artery. Conclusion: Comprehensive analysis of the perfusion maps and CTPA of dual source CT low - dose contrast perfusion imaging will improve theaccuracy of diagnosis of PE.