Quantitative assessment of aortic wall thickening disease by dual energy computed tomography angiography

Abstract

A broad spectrum of etiologies can lead to aortic wall thickening. This study aimed to evaluate the utility of quantitative parameters derived from dual-layer computed tomography (CT) in differentiating intramural hematoma (IMH), non-calcified plaques, and aortic thrombosis, and to explore their associations with laboratory inflammatory markers. 365 patients were retrospectively enrolled, including atherosclerosis ( n  = 98), aortic dissection ( n  = 126), and IMH ( n  = 141). Laboratory indicators were collected from the electronic medical record system. Regions of interest (ROI) of non-calcified plaques, thrombi, hematomas, and periaortic adipose tissue around lesions were outlined. The lesion enhancement values and degree of enhancement were calculated from the CT values in polyenergetic and virtual non-contrast image. The slope of the energy spectrum curve was determined using the formula: K = (CT 40keV - CT 100keV ) / 60. Normalization was performed for the effective atomic number (Z), iodine density (ID), and iodine non-water density (IW) using the aortic lumen as the standard reference, resulting in normalized Z values, normalized iodine density (NID), and normalized iodine non-water density (NIW). The enhancement values and degrees of enhancement differed among the three lesions (all P  < 0.05). Differences in Z value, ID, IW, and K were observed among non-calcified plaques, thrombi, and hematomas (all P  < 0.05). The NID of hematoma was the largest, while the NIW of thrombus was the smallest. Normalized Z value of non-calcified plaque was significantly smaller than those of thrombus and hematoma (both P  < 0.05), with no difference between thrombus and hematoma ( P  > 0.05). The Z periaortic fat pre- and post-normalization were significantly smaller around the plaques than around the thrombi and hematomas (both P  < 0.05). Significant correlations were found between aortic wall normalized Z lesion , Z periaortic fat , and laboratory parameters, including neutrophil % and neutrophil count, lymphocyte % and lymphocyte count, C-reactive protein, and D-dimer. Quantitative spectral CT parameters show promise for the non-invasive identification of aortic wall lesions. The weak correlations with laboratory inflammatory markers suggest a potential but limited link between imaging parameters and local inflammation. These exploratory findings require further validation. If confirmed in future studies, this approach may complement conventional CTA and guide targeted therapy. Not applicable.