🦴 Bone Density Interpretation (DXA T/Z-score, QCT, Opportunistic CT HU)
UseBone density imaging: DXA, QCT and opportunistic routine CT — osteoporosis diagnosis and referral.
SourceWHO. Assessment of fracture risk and its application to screening for postmenopausal osteoporosis. …
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
Paste the link in Slack, Teams, X, or LinkedIn — the preview image comes from this page’s Open Graph card.
Methodology · worked example, guidelines & full notes
DXA: lowest T-score of L1–L4 (exclude fractured / degenerated levels, keep ≥ 2), femoral neck and total hip; T-score for postmenopausal women and men ≥ 50, Z-score for premenopausal women, men < 50 and children.
When to use
Bone density imaging: DXA, QCT and opportunistic routine CT — osteoporosis diagnosis and referral.
How it works
T-score (lowest site) ≤ −2.5: osteoporosis T-score (lowest site) −2.5 < T < −1: low bone mass (osteopenia) T-score (lowest site) ≥ −1: normal Z-score ≤ −2.0: below expected range for age (avoid 'osteoporosis'; look for secondary causes) Z-score > −2.0: within expected range for age QCT lumbar vBMD < 80: osteoporosis QCT lumbar vBMD 80–120: low bone mass QCT lumbar vBMD > 120: normal L1 attenuation < 100 HU: osteoporosis likely — recommend DXA L1 attenuation 100–150 HU: low bone mass possible — consider DXA L1 attenuation ≥ 150 HU: osteoporosis unlikely
Key points
- DXA: lowest T-score of L1–L4 (exclude fractured / degenerated levels, keep ≥ 2), femoral neck and total hip; T-score for postmenopausal women and men ≥ 50, Z-score for premenopausal women, men < 50 and children.
- Each value is graded against published reference ranges.
- Measurement technique and positioning change the numbers — compare like with like on follow-up.
- Part of the YuanDoctor MSK measurement topic.
References
- [Guideline / primary source]WHO. Assessment of fracture risk and its application to screening for postmenopausal osteoporosis. Technical Report Series 843, 1994
- [Guideline / primary source]ACR–SPR–SSR Practice Parameter for the Performance of Quantitative CT Bone Densitometry (2018)
- [Guideline / primary source]中国定量 CT（QCT）骨质疏松症诊断指南（2018）
- ISCD Official Positions — Adult 2023
- Pickhardt PJ, et al. Opportunistic screening for osteoporosis using abdominal CT scans obtained for other indications. Ann Intern Med 2013;158:588-595
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Method | QCT (mg/cm³) |
|---|---|
| Fragility fracture (hip / vertebra, etc.) | No |
| QCT lumbar vBMD | 95 mg/cm³ |
→QCT lumbar vBMD95mg/cm³
- QCT lumbar vBMD：95 mg/cm³ → 80–120: low bone mass
| Method | DXA |
|---|---|
| Population (DXA) | Postmenopausal women / men ≥ 50 (T-score) |
| Fragility fracture (hip / vertebra, etc.) | No |
| T-score (lowest site) | -2.7 |
→T-score (lowest site)-2.7
- T-score (lowest site)：-2.7 → ≤ −2.5: osteoporosis
Verification & sources · governance
FAQ
Frequently asked questions
- What are the limits and cautions when using Bone Density Interpretation (DXA T/Z-score, QCT, Opportunistic CT HU)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- Does Bone Density Interpretation (DXA T/Z-score, QCT, Opportunistic CT HU) upload patient data? Where is it calculated?
- Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
- How is Bone Density Interpretation (DXA T/Z-score, QCT, Opportunistic CT HU) calculated in practice? Can you show a worked example?
- Inputs: Method QCT (mg/cm³), Fragility fracture (hip / vertebra, etc.) No, QCT lumbar vBMD 95 mg/cm³ → Result: QCT lumbar vBMD 95 mg/cm³（QCT lumbar vBMD: 95 mg/cm³ → 80–120: low bone mass） Inputs: Method DXA, Population (DXA) Postmenopausal women / men ≥ 50 (T-score), Fragility fracture (hip / vertebra, etc.) No, T-score (lowest site) -2.7 → Result: T-score (lowest site) -2.7（T-score (lowest site): -2.7 → ≤ −2.5: osteoporosis）