Quantitative Assessment of Abdominal Aortic Calcifications Using Lateral Lumbar Radiograph, Dual-Energy X-ray Absorptiometry, and Quantitative Computed Tomography of the Spine

Abstract

Abdominal aortic calcifications (AACs) represent an independent determinant of cardiovascular events and are strongly associated with cardiovascular disease. To our knowledge, a comparison between lateral lumbar radiography, lateral spine dual-energy x-ray absorptiometry (DXA), and quantitative computed tomography (QCT) in the assessment of AAC has not been performed. Our objective was to compare those methods in the detection and quantification of AAC using a simplified 8-point score system (AAC-8). Three hundred twenty-three postmenopausal women underwent lateral lumbar radiography, lateral spine DXA, and QCT for osteoporosis screening and were scored for AAC using the AAC-8. Lateral lumbar radiographs, lateral spine DXA, and QCT detected AAC in 58%, 55%, and 60% of the subjects, respectively. The nonparametric intraclass correlation coefficient between lateral lumbar radiograph and lateral spine DXA and lateral lumbar radiograph and QCT were 0.699 (95% confidence interval [CI]: 0.638–0.752) and 0.829 (95% CI: 0.783–0.865). Area under operating curve (receiver operating characteristic [ROC]) for lateral spine DXA was 0.826 (95% CI: 0.764–0.888), whereas for QCT was 0.948 (95% CI: 0.922–0.974) considering lateral lumbar radiograph as gold standard. AAC has been shown to be a significant predictive marker of overall cardiovascular disease. DXA may be a screening tool among asymptomatic patients with low radiation exposure to identify an important cardiovascular disease risk factor. QCT represents a reliable technique that may be applied as a future standard to facilitate the detection of abdominal aortic calcification as well as to provide more accurate measurement of bone densitometry.