CT ‘likely a more accurate measure’ of volumetric BMD
Dr. Pickhardt said the differences in osteoporosis prevalence observed between DXA and CT-derived measures in men likely reflect the greater accuracy of CT.
“DXA is a planar technique with a number of drawbacks,” he said in an interview. “CT provides a more direct volumetric measure and is likely a more accurate method for BMD assessment.”
He speculated that the greater differences between DXA versus CT seen in men than women “may relate to sex differences in cortical bone of vertebral bodies, which cannot be separated from the underlying trabecular bone with DXA (whereas CT directly measures the inner trabecular bone).”
The authors note that, although areal BMD (aBMD) derived from DXA is required for osteoporosis diagnosis according to World Health Organization criteria, “trabecular vBMD derived from CT can be also used for diagnosis based on thresholds published by the American College of Radiology of 120 mg/cm3 and 80 mg/cm3 to define osteopenia and osteoporosis, respectively, thresholds that were subsequently confirmed for the Chinese population.”
Furthermore, vBMD has been shown in some studies to be more strongly related to fracture risk, compared with DXA aBMD measures.
Importantly, in another recent study involving 9,223 adults, Dr. Pickhardt and colleagues reported that bone and muscle biomarkers derived from CT were comparable to the Fracture Risk Assessment Tool score for the presymptomatic prediction of future osteoporotic fractures.
Dr. Pickhardt is an advisor to Bracco Imaging and Zebra Medical Vision. Dr. Therkildsen has reported no relevant financial relationships.
This article first appeared on Medscape.com.