Abdominal aortic calcification and its distribution in normal-sized and aneurysmatic abdominal aortas

Abstract

Multi-detector computed tomography (MDCT) is more and more used for evaluation and quantification of coronary artery calcification, but correlation between the degree of calcification and occurrence of clinical events is also known for other vascular beds such as the aorta. To assess possible differences in amount and pattern of calcification in aneurysmatic and non-aneurysmatic abdominal aortas. Thirty-four subjects displayed infrarenal abdominal aneurysm (AAA) and were compared to 33 patients with normal-sized aortas using MDCT. Quantitative and qualitative analysis was performed by two radiologists. Calcium scores were assessed for the whole abdominal aorta as well as separately for the supra- and infrarenal segments. Moreover, plaque patterns were evaluated and classified according to their thickness and size. Furthermore, calcium scores were correlated with a number of cardiovascular risk factors. Total calcium scores were comparable in patients with and without AAA (1,213 ± 1,351 and 1,211 ± 1,535, respectively), but significant differences were found regarding plaque density that was considerably higher both in the supra- and infrarenal segments in the non-aneurysmatic group (AAA: suprarenal, 0.01, infrarenal, 0.07; non-AAA: suprarenal, 0.06, infrarenal, 0.16). Plaque pattern were considerably different in the infrarenal segments in aneurysmatic aortas: they were thinner (1 and 2 mm) and smaller (< 100 mm2) than in normal-sized aortas (mainly > 3mm and > 100 mm2). Distribution of risk factors was similar in both groups with the highest mean calcium score being present in patients with 4 risk factors. Pearson's correlation coefficient indicating correlation between total calcium score and number of risk factors was almost the same in both groups: AAA, r = 0.67; non-AAA, r = 0.65. Compared to normal-sized aortas thinner and smaller plaques are present in AAA, which may be due to degenerative processes.