Do petite women get over-diagnosed with osteoporosis?

The discrepancy can be as much as 20% because the imaging is 2d (areal) which can't detect the difference between small dense bone and large sparce bone. Dexa's TBS attempts to quantify bone homogeneity to address this discrepancy.
The doctor I see ordered a special CT scan. The results were the same as dexa.

@gently What was the special CT scan called? I have 2 vertebrae that were eliminated due to sclerosis and I found this "If only two vertebrae are left, because the other vertebrae have been eliminated or both hips have been excluded because of hip replacements, then a lateral vertebral assessment (LVA) — a DXA of the mid and upper back or lateral thoracic x-ray — should be done." Has anyone had a LVA done?

loplady, hi,
https://nyimaging.com/news/understanding-quantitative-computed-tomography-qct-for-bone-density-testing

I've wondered about this myself, as I've been diagnosed with severe osteoporosis (-4.1 in spine and -2.7 in hips) and am petite at 5'3" and 120 lbs..

Here is one article about this: https://betterbones.com/osteoporosis/bone-density-testing-do-small-boned-women-get-a-fair-shake/

@daisy17 Thanks for this!

@gently
hello are you then saying that since your CT scan gave same results as DEXA, that then negates the questionable discrepancy with small boned people?

laren3, W
the discrepancy in inherent in the 2-dimensional dexa measurement. With a dexa score, the actual bmd would be higher in a small bone than it would be in a large bone because dexa doesn't register volume of the bone.
The numbers generated through dexa and QCT can't be directly compared.
Because I have an older spine, the concern was that dexa might be giving me a better T score by including bone spurs. With a lower score, I might have chosen a different medication (Tymlos instead of Forteo).
QCT measures trabecular bone the more delicate inner portion of the vertebrae and femoral neck. Dexa measures both cortical and trabecular bone

@gently Are you saying the DEXA score would show worse osteoporosis for smaller bones vs larger bones? Wouldn't a worse DEXA score indicate less BMD in the smaller bones?

@daisy17, I see the sense of what you are saying.
But, the dexa score would be the same no matter the size of the bone. The dexa score might be sufficient in a small bone where the same score would be insufficient in a larger bone. So, without calculating for bone size, a person with small bones might be (over) diagnosed as osteoporotic.
A large glass of water needs more sugar to be as sweet as a small glass of water. If you count the particles of sugar in a glass without assessing how full the glass is the count of sugar particles doesn't account for the dilution.
Ten particles of sugar in a full glass will be less sweet than ten particles in glass that is half full.
TBS uses a grey scale to calculate the space between particles giving us a fracture risk based on homogeneity.

@gently Thank you for your reply and especially that last sentence was very helpful