Table 2. Diagnosis of osteoporosis using QCT measurement of lumbar spine bone density.

Diagnosis	Lumbar spine bone density value*
Normal	Volumetric bone density >120 mg/cm3
Low bone density	80 mg/cm3 ≤ volumetric bone density ≤120 mg/cm3
Osteoporosis	Volumetric bone density <80 mg/cm3
Severe osteoporosis	Volumetric bone density <80 mg/cm3 with an insufficiency fracture

*, lumbar spine bone mineral density value is the average value of the volumetric bone mineral density measurements obtained from cancellous bone in two lumbar spine vertebral bodies. This standard is suitable for use in post-menopausal women and elderly men. When there is decreased BMD in younger patients, further evaluation should be conducted to exclude secondary causes. When using QCT to diagnose osteoporosis, measuring one area is sufficient and the choice is between spine and hip based on clinical need.