Growth patterns of abdominal atherosclerotic calcified deposits from lumbar lateral X-rays

The aim of this study is to investigate new methods for describing the progression of atherosclerosis based on novel information of the growth patterns of individual abdominal aortic calcifications (AACs) over time. Lateral X-ray images were used due to their low cost, fast examination time, and wide-spread use, which facilitates a large statistical model (n > 100) based on longitudinal data. The examined cohort consisted of 103 post-menopausal women aged 62.4 years (± 7.0 years) with an average number of AACs of (4.7 ± 8.0) at baseline. The subjects had X-ray images taken in 1992-1993 (baseline) and again in 2000-2001 (follow-up). The growth patterns of the individual AACs were derived based on registered baseline and follow-up images. Area, height, width, centre of mass position, and movement of the centre of mass, and upper and lower boundary of the matched AACs were measured. The AACs occurred first, mainly, on the posterior aortic wall. The AACs grew on average 41 in the longitudinal direction and 21 in the radial direction. A correlation of 0.48 (P < 0.001) between growth in width and height of the AACs was present. The centre of mass of the AACs moved 0.60 mm (P < 0.001) downstream in the aorta, on average. The growth patterns of AACs may give new insights into the progression of atherosclerosis. The downstream asymmetry in the growth patterns indicates variability in microscopic environments around the AACs.