Figure 2. Normal and abnormal L3 vertebral attenuation measurements using the simple ROI method.
A. Non-angled transverse CTC image with vertebral ROI at the L3 level shows a trabecular attenuation of 204.5 HU, well above the 145 HU level-specific threshold for 100% osteoporosis sensitivity (Table 1). L-spine DXA T-score was 0.6.
B. L3 vertebral ROI shows an attenuation of 80.5 HU in a patient with osteoporosis at DXA (L-spine T-score=−2.9), which is well below the 145 HU threshold.