Effect of Age on Active and Structural Magnetic Resonance Imaging Lesions in Sacroiliac Joints of Healthy Individuals and Patients With Nonspecific Back Pain
Bibliographic record
Abstract
OBJECTIVE: To assess the effect of increasing age on the frequency of inflammatory and structural magnetic resonance imaging (MRI) lesions in the sacroiliac joints (SIJ) in 3 independent cohorts of healthy individuals and patients with nonspecific back pain (NSBP). METHODS: We assessed MRI SIJ lesions in 3 cohorts (A, B, and C) of healthy individuals (cohort A, n = 79; cohort B, n = 78) and patients with NSBP (cohort A, n = 87; cohort C, n = 46) aged ≤ 45 years referred with back pain suspicious of axial spondyloarthritis (axSpA). MRI lesions were recorded on consecutive slices in SIJ quadrants or halves through the cartilaginous SIJ. Lesions were ascertained by 2-7 central readers according to standardized lesion definitions. Lesions recorded concordantly by the majority of readers were analyzed according to age categories (18-29, 30-39, and 40-50 yrs) and previously reported data-driven MRI cutoffs indicative of inflammatory or structural lesions typical of axSpA. RESULTS: Only 3.8% (in both cohort A and cohort B) of healthy individuals and 5.7% (cohort A) and 4.3% (cohort C) of patients with NSBP had erosion in ≥ 1 SIJ quadrant, and progressive increases of erosion with age categories were not evident. None of the healthy individuals and 2.3% and 4.3% of cohort A and cohort C, respectively, of the patients with NSBP showed erosion in ≥ 3 SIJ quadrants, the cutoff indicative of axSpA; not a single individual met this cutoff in the highest age category. Fat metaplasia was slightly increased with age among healthy individuals and patients with NSBP in cohort A, but not in cohorts B or C. CONCLUSION: SIJ MRI data from healthy individuals and NSBP controls did not indicate progressive increases in structural lesions with increasing age categories when standardized definitions for axSpA lesions were adopted. MRI cutoffs for structural lesions denoting axSpA discriminated equally well between axSpA and NSBP across all age categories.
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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 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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".