Introduction Aortic valve calcification (AVC) has been proposed as the main force driving progression of aortic stenosis. Non-contrast computed tomography (CT) can reproducibly quantify AVC and correlates well with echocardiographic measures of severity. However, contrast-enhanced CT presents the opportunity to quantify AVC whilst also providing important information about spatial distribution of calcium and non-calcific thickening of leaflets.

Methods CT scans of 113 consecutive patients assessed for transcatheter aortic valve implantation (TAVI) at the Edinburgh Royal Infirmary were analysed. Contrast-enhanced CT images were reconstructed in the short-axis plane of the aortic valve to measure valve dimensions, quantify AVC (volume, mm³) and document spatial distribution of calcium. Three methods were compared for defining the radiodensity threshold above which calcium was detected and a scoring system was applied to describe calcium distribution.

Results AVC can be detected using contrast-enhanced CT and is likely to benefit from a threshold adjusted according to contrast load. Males were found to have higher AVC volume than females (mean 1069mm³ vs. 817.7 mm³, p=0.0058), even when adjusted for annular diameter (p=0.0435). The non-coronary cusp was the most heavily calcified cusp (p<0.001) and a correlation was seen between increasing cusp calcification and progressive involvement of the free edge tending toward a complete arc of calcium.

Conclusions Contrast-enhanced CT allows for quantification of AVC and the optimal method must now be validated against non-contrast CT. Contrast CT provides valuable additional information about valve anatomy and AVC location which are likely to contribute to the haemodynamic severity of aortic stenosis.