Quantitative CT Measurement Of Cross-sectionalarea Of Small Pulmonary Vessel In Ards:Does It Work?

Background: Acute respiratory distress syndrome(ARDS)refers to a generalized inflammation of the lung parenchyma,caused by different diseases.Direct or indirect insults result in neutrophil and platelet-dependent dysfunction of the alveolar-epithelial barrier,Induce alveolar edema,alveolar collapse,and destruction of the pulmonary microvascular bed.pulmonary vascular disorders play an important role in the development of ARDS.Now many people think that evaluate vascular Morphology and amounts will open a door for further understanding of ARDS in Pathophysiological changes.AS The Berlin definition of ARDS,CT is a really good way to diagnose and evaluate the conditions of ARDS.Qautative CT allows a sort of quantitative anatomy “in vivo”,provides clinicians with a comprehensive evaluation of lung parenchyma,pleural space,heart and thoracic vessels,soft tissue,and mediastinum.CT angiography used to evaluate the thrombus in lung,but it has some possible harm,such as X-ray exposure and contrast-induced kidney injury.Nowadays,Qautative CT improves its resolution and provides some Slightstructures,therefore some people use it for evaluate the Pathophysiological changes in COPD.A reseach indict that the cross-sectional area(CSA)is significantly correlated with pulmonary perfusion.Objective: Assessing the differences of total cross-sectional area of small pulmonary vessels between the ARDS and normal.Methods:Retrospective analysis of the CT data of the ARDS group and the normal control group by age and sex,then Selecting CT pictures images that can represent the upper,middle,and lower lung fields,finanlly measuring CSA less than 10 mm2 and calculated the percentage of the total CSA for the lung area(%CSA),then analyzes %CSA between all levels.Results: This study comprised 27 subjects who diagnosis ARDS,and matched with 27 controls using age and sex.there was significant difference in ARDS group and control group for every single slices(P<0.001),and also in sum of three slices.the %CSA of ARDS CT levels is 0.027(0.018-0.037)?0.024(0.017-0.036)?0.018(0.013-0.034),the control is 0.113(0.064-0.146)?0.100(0.079-0.130)?0.124(0.092-0.283),and the sum of all levels is 0.067(0.048-0.101)?0.348(0.232-0.627).Conclusions: Quantative CT can detect the pulmonary changes in ARDS,and the %CSA could be an index of pulmonary vascular in ARDS.