Assessment of disease activity in Takayasu arteritis based on perivascular fat CT values from aortic CTA

OUYANG Meixiang; CHEN baojin; LI Ju; WANG Xinyi; ZOU Yuting; WANG Cuiyan

doi:10.20258/j.cnki.1006-9011.2025.05.007

Abstract：Objective To evaluate the value of perivascular fat CT values based on aortic CT angiography(CTA)in assess-ing disease activity in Takayasu arteritis(TAK).Methods Clinical data and aortic CTA images of 55 TAK patients were retro-spectively analyzed.Based on the ITAS-A scoring criteria,patients were divided into an active group(n=25)and an inactive group(n=30).The arterial lumen changes(including stenosis,occlusion,and dilation)and arterial wall characteristics(includ-ing wall thickness,low-density ring sign,delayed enhancement,and calcification)were assessed on CTA images.Additionally,the CT values and relative values of perivascular fat were measured at the thickest part of the arterial wall.Receiver operating characteristic(ROC)curve analysis was performed to evaluate the predictive value of perivascular fat CT values and relative val-ues for disease activity in ATK.Results The proportions of lumen stenosis and occlusion in different arterial segments were consistently higher than those of lumen dilation/aneurysm.The left common carotid artery and left subclavian artery were the most commonly involved segments,while coronary artery and pulmonary artery involvement were relatively rare.Both groups exhibited circumferential wall thickening,with the active group demonstrating significantly greater wall thickness,higher prevalence of low-density ring signs,and more frequent delayed wall enhancement compared to the inactive group(all P<0.01).The active group showed significantly higher perivascular fat CT values and lower relative perivascular fat values than the inactive group(both P<0.01).ROC curve analysis revealed that perivascular fat CT values predicted TAK disease activity with 83.3%of sensi-tivity and 92.0%of specificity,while relative perivascular fat values showed 86.7%of sensitivity and 88.0%of specificity.The AUC values for perivascular fat CT values and relative values in predicting TAK disease activity were 0.896(95%CI:0.807-0.985,P<0.001)and 0.909(95%CI:0.828-0.990,P<0.001)respectively,with both superior to those of arterial wall character-istics.Conclusion The perivascular fat CT values are elevated in patients with active TAK and the perivascular fat CT values based on aortic CTA are effective indicators for predicting TAK activity.