Aortic stenosis is a common clinical condition that is set to increase in prevalence with an ageing population. However, reliable methods for predicting disease progression and effective medical therapies are lacking. Inflammation and calcification are believed to have a key role but until recently the relative contributions of these processes at the different stages of the disease process were unknown. Recent studies have suggested that combined positron emission tomography and computed tomography (PET/CT) is a feasible and reproducible method for measuring the degree of inflammation and calcification in the valves of patients with aortic stenosis. For the first time this provides us with a potential method of measuring disease activity, which might then allow prediction of progression and act as a surrogate endpoint in studies of novel therapies. In this review, we will examine the basis for PET/CT scanning and discuss the studies that have investigated its use in aortic stenosis. We will cover the work that is still required in order to validate this technique and how it might impact on future clinical research and practice. Finally, we will examine alternative imaging methods that might also provide insight in to the underlying pathogenesis of this important and common clinical condition.