Detection of abdominal aortic calcification with lateral spine imaging using DXA

Abstract

Radiographic abdominal aortic calcification (AAC) is associated with incident cardiovascular disease and mortality independent of other risk factors. Lateral spine imaging using dual-energy X-ray absorptiometry (DXA) is now available to detect prevalent vertebral fracture (called vertebral fracture assessment), but its potential utility to detect radiographic AAC has not been investigated. Fifty-seven of 205 women age 65 or older who had participated in a prior study of the detection of prevalent vertebral fracture with lateral DXA had technically adequate radiographs and lateral DXA images to assess AAC. Two readers scored both the radiographic and lateral DXA images for AAC using a previously validated 24-point scale, blinded to both of each other's readings and also to their own readings on the other technology. The agreement between radiograph and lateral DXA AAC scores was very good (intra-class correlation coefficient [ICC] of 0.81 (95% confidence interval [CI]: 0.66-0.90) for reader 1 and 0.82 (95% CI: 0.69-0.90) for reader 2). The ICC between the two reader's AAC scores on radiographs was 0.92 (95% CI: 0.88-0.95) and on lateral DXA images was 0.89 (95% CI: 0.80-0.94). Lateral spine imaging with DXA shows very good agreement with standard radiography in the detection of AAC. Lateral imaging of the spine with DXA intended to detect vertebral fracture is a promising technology for the simultaneous assessment of a risk factor for cardiovascular disease incidence and death.