Grillet Franck, Busse-Coté Andreas, Calame Paul, Behr Julien, Delabrousse Eric, Aubry Sébastien
Department of Radiology, Centre Hospitalier Universitaire de Besancon, Besancon, France.
Nanomedecine Laboratory EA4662, University of Franche-Comte, Besancon, France.
Quant Imaging Med Surg. 2020 Sep;10(9):1852-1862. doi: 10.21037/qims-20-708.
Increased prevalence of acute pulmonary embolism in COVID-19 has been reported in few recent studies. Some works have highlighted pathological changes on lung microvasculature with local pulmonary intravascular coagulopathy that may explain pulmonary artery thrombosis found on pulmonary computed tomography (CT) angiography. The objective of our study was to describe lung perfusion disorders assessed by pulmonary dual-energy CT (DECT) angiography in severe COVID-19 patients.
This single center retrospective study included 85 consecutive patients with a reverse transcriptase-polymerase chain reaction diagnosis of SARS-CoV-2 who underwent a pulmonary DECT angiography between March 16 2020 and April 22 2020. Pulmonary DECT angiography was performed when the patient had severe clinical symptoms or suffered from active neoplasia or immunosuppression. Two chest radiologists performed pulmonary angiography analysis in search of pulmonary artery thrombosis and a blinded semi quantitative analysis of iodine color maps focusing on the presence of parenchymal ischemia. The lung parenchyma was divided into volumes based on HU values. DECT analysis included lung segmentation, total lungs volume and distribution of lung perfusion assessment.
Twenty-nine patients (34%) were diagnosed with pulmonary artery thrombosis, mainly segmental (83%). Semi-quantitative analysis revealed parenchymal ischemia in 68% patients of the overall population, with no significant difference regarding absence or presence of pulmonary artery thrombosis (23 . 35, P=0.144). Inter-reader agreement of parenchymal ischemia between reader 1 and 2 was substantial [0.74; interquartile range (IQR): 0.59-0.89]. Volume of ischemia was significantly higher in patients with pulmonary artery thrombosis [29 (IQR, 8-100) 8 (IQR, 0-45) cm, P=0.041]. Lung parenchyma was divided between normal parenchyma (59%, of which 34% was hypoperfused), ground glass opacities (10%, of which 20% was hypoperfused) and consolidation (31%, of which 10% was hypoperfused).
Pulmonary perfusion evaluated by iodine concentration maps shows extreme heterogeneity in COVID-19 patients and lower iodine levels in normal parenchyma. Pulmonary ischemic areas were more frequent and larger in patients with pulmonary artery thrombosis. Pulmonary DECT angiography revealed a significant number of pulmonary ischemic areas even in the absence of visible pulmonary arterial thrombosis. This may reflect microthrombosis associated with COVID-19 pneumonia.
最近的一些研究报道了新冠病毒疾病（COVID-19）中急性肺栓塞患病率增加。一些研究强调了肺微血管的病理变化以及局部肺血管内凝血病变，这可能解释了在肺部计算机断层扫描（CT）血管造影中发现的肺动脉血栓形成。我们研究的目的是描述通过肺部双能CT（DECT）血管造影评估的重症COVID-19患者的肺灌注障碍。
这项单中心回顾性研究纳入了85例连续的经逆转录聚合酶链反应诊断为严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的患者，这些患者于2020年3月16日至2020年4月22日期间接受了肺部DECT血管造影检查。当患者出现严重临床症状或患有活动性肿瘤或免疫抑制时，进行肺部DECT血管造影。两名胸部放射科医生进行肺血管造影分析以寻找肺动脉血栓形成，并对碘色图进行盲法半定量分析，重点关注实质缺血的存在情况。根据HU值将肺实质划分为不同体积。DECT分析包括肺分割、全肺体积和肺灌注分布评估。
29例患者（34%）被诊断为肺动脉血栓形成，主要为节段性（83%）。半定量分析显示，总体人群中68%的患者存在实质缺血，有无肺动脉血栓形成之间无显著差异（23.35，P = 0.144）。读者1和读者2之间关于实质缺血的阅片者间一致性较高[0.74；四分位间距（IQR）：0.59 - 0.89]。肺动脉血栓形成患者的缺血体积显著更高[29（IQR，8 - 100）对8（IQR，0 - 45）cm³，P = 0.041]。肺实质分为正常实质（59%，其中34%灌注不足）、磨玻璃影（10%，其中20%灌注不足）和实变（31%，其中10%灌注不足）。
通过碘浓度图评估的肺灌注在COVID-19患者中显示出极大的异质性，正常实质中的碘水平较低。肺动脉血栓形成患者的肺缺血区域更频繁且更大。即使在没有可见肺动脉血栓形成的情况下，肺部DECT血管造影也显示出大量的肺缺血区域。这可能反映了与COVID-19肺炎相关的微血栓形成。
