How to assess aortic stenosis using computed tomography: Current and emerging tools

Abstract Aortic stenosis (AS) is the most common valvular heart disease characterized by progressive calcific degeneration of the aortic valve leaflets, ultimately leading to severe left ventricular (LV) outflow obstruction. Accurate assessment of AS severity is critical for appropriate clinical decision-making. While echocardiography remains the cornerstone of AS evaluation, it can yield discordant results in around a quarter of patients often leading to diagnostic uncertainty. In patients with discordant echocardiography, non-contrast computed tomography aortic valve calcium scoring (CT-AVC) has emerged as a powerful adjunctive modality that offers load-independent, highly reproducible quantification of valvular calcification and a complementary assessment of AS severity. In addition, contrast-enhanced computed tomography (CT) has become the gold standard for preprocedural assessment in transcatheter aortic valve implantation (TAVI) patients, providing a comprehensive anatomical visualization of the cardiovascular system which is essential for optimal planning. It allows for precise measurement of the aortic annulus, identification of coronary artery origins, assessment of peripheral vascular access, and evaluation of the aortic root and ascending aorta. This detailed anatomical assessment facilitates accurate prosthesis sizing and selection, reducing the risk of complications such as paravalvular leak and coronary artery obstruction. Advanced CT imaging techniques are being developed to further advance the assessment of patients with AS. In particular, contrast-enhanced CT techniques allow for the quantification of both fibrotic and calcific aortic valve thickening, while CT-derived strain imaging and extracellular volume (ECV) quantification provide a better assessment of the myocardial remodeling response (Figure 1).