PQCT MEASUREMENTS OF BONE MASS, DENSITY, GEOMETRY AND STRUCTURE AT THE DISTAL RADIUS: PREDICTION OF BONE STRENGTH, AND THE IN VIVO EFFECTS OF PHARMACOLOGICAL TREATMENTS FOR OSTEOPOROSIS
Bibliographic record
Abstract
This work encompasses two primary studies utilizing peripheral quantitative computed tomography (PQCT) in the assessment of bone characteristics at the distal radius. PQCT enables separate analyses of cortical, trabecular and total bone density, content and geometry. Further analysis of the pQCT image with specialized software permits in vivo trabecular structure assessment. The first study is a two-year prospective trial evaluating the effects of five different medication regimens (hormone replacement therapy (HRT), etidronate , alendronate, etidronate plus HRT and alendronate plus HRT) used for the treatment of osteoporosis in 123 postmenopausal women with low bone mass. Results of analyses on baseline data found that trabecular structure indices could significantly discriminate between osteoporotic and osteopenic groups of women. Longitudinal data at the lumbar spine (LS) and femoral neck (FN) for women taking any medication ('Any-Tx') showed similar results to those of large clinical trials. For example, the 'Any-Tx' group gained significant bone mineral density (BMD) over baseline at 2 years at the LS (5.5%, p<0.001) and FN (1.6%, p<0.05). Women on combination therapy gained significantly more BMD than women taking one medication over 2 years at the LS and FN. Data suggests that alendronate plus HRT may produce the largest BMD gains at the LS and FN at 2 years. Longitudinal pQCT data for total, cortical and trabecular compartments at the distal radius in the control group over the 2 years suggest endocortical resorption and trabecular thinning with age. PQCT data in the 'Any-Tx' group show gains in total and cortical bone density and cortical content, but losses in trabecular density, content and area. This suggests that anti-resorptive medications promote endocoritcal apposition and reduce intracortical porosity. The second study evaluated five different clinical measurement tools in the prediction of in vitro failure load at the distal radius and found that cortical content measured by pQCT was a significantly better predictor than ultrasound or digital x-ray radiogrammetry.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".