非肺栓塞灌注缺损的双源CT双能量肺灌注成像表现及原因

目的 分析双源CT双能量肺灌注成像(DEPI)中非肺栓塞引起的灌注缺损(PDs)的原因及其影像学表现特征.方法 回顾性分析行DEPI扫描而确诊无肺栓塞的208例患者的影像学资料.由2位影像科医生分析PDs原因,统计不同原因所致PDs的肺段数量、所占比例、形态、灌注表现类型等,分析各种原因引起PDs的影像特征.结果 208例患者中,共有1 118个肺段出现PDs,引起PDs的原因包括4类:肺内病变、血管性病变、伪影类及原因不明者,受累肺段数目分别为752(67.26%)、36(3.22%)、308(27.55%)、22(1.97%).观察肺内病变、血管性病变以及原因不明者所致PDs,将其灌注表现类型分为3种:楔形分布、不均匀分布、区域性均匀分布.上述病变灌注类型以不均匀、区域性均匀分布为主,与非灌注图像所示病变形态基本一致.伪影类包括2大类:对比剂所致局部线束硬化伪影、运动伪影.不同原因伪影所致PDs常有其特点部位及形态.结论 认识非肺栓塞所致PDs的影像特征有助于提高DEPI诊断肺栓塞的准确性.

The manifestations and causes of non-pulmonary embolism inducedperfusion defects on dual-energy perfusion imaging using dual source CT

Objective To analyze the causes and manifestations of non-pulmonary embolism induced perfusion defects (PDs) on dual-energy perfusion imaging (DEPI) using dual source CT.Methods Consecutive 208 patients without pulmonary embolism who underwent DEPI were reviewed retrospectively.The causes of PDs were analyzed by two radiologists, the pulmonary segment numbers, the proportion and the perfusion patterns of each case were recorded and analyzed respectively.Results 1 118 of 3 716 pulmonary segments showed the PDs.Among them, 752(67.26%), 36(3.22%), 308(27.55%) and 22(1.97%) pulmonary segments had PDs due to intra-pulmonary lesions, vascular diseases, artifacts and unidentifiable causes, respectively.In PDs resulted from intra-pulmonary lesions, vascular diseases and unidentifiable causes, three patterns (wedge-shaped, heterogeneous and regionally homogeneous) were identified,and most of those PDs were heterogeneous and regionally homogeneous, which were largely in accordance with the lesions showed on non-contrast enhanced scans.Artifacts included the beam hardening artifacts and artifacts caused by heart beat or diaphragmatic movement.The PDs caused by artifacts usually had particular locations and shapes.Conclusion Understanding of the manifestations and causes of PDs in patients without pulmonary embolism can improve the diagnosis accuracy of pulmonary embolism on DEPI.