Hybrid 18F-labeled Fluoride Positron Emission Tomography/Magnetic Resonance (MR) Imaging of the Sacroiliac Joints and the Spine in Patients with Axial Spondyloarthritis: A Pilot Study Exploring the Link of MR Bone Pathologies and Increased Osteoblastic Activity
Bibliographic record
Abstract
OBJECTIVE: The biologically active molecule used in positron emission tomography (PET) for depiction of osteoblastic activity is 18F-labeled fluoride (18F-F). We examined whether inflammatory or chronic changes on magnetic resonance imaging (MRI) in the sacroiliac joints (SIJ) and the spines of patients with active ankylosing spondylitis (AS) are linked to osteoblastic activity, assessed by PET/MRI. METHODS: Thirteen patients with AS (mean age 37.8 ± 11.4 yrs, Bath AS Disease Activity Index > 4, no anti-TNF treatment) underwent 3-Tesla whole-spine and SIJ PET/MRI. Two independent readers recorded pathologic changes related to vertebral (VQ) or SIJ quadrants (SQ). Final scores were based on reader agreement. RESULTS: A total of 104 SQ and 1196 VQ were examined. In SIJ, bone marrow edema (BME) was seen in 44.2%, fat deposition (FD) in 42.3%, and 18F-F in 46.2% SQ. BME alone was associated with 18F-F in 78.6% and FD alone in only 7.7% SQ, while the combination BME/FD was associated with 18F-F in 72.2% SQ. Erosions, sclerosis, and ankylosis alone were rarely associated with 18F-F. In the spine, BME alone was seen in 9.9%, FD in 18.2%, and 18F-F in 5.4% VQ. BME alone was associated with 18F-F in 14.3% and FD alone in 8.7% VQ, while the combination BME/FD was associated with 18F-F in 40.6% VQ. CONCLUSION: In this study of hybrid 18F-F PET/MRI of patients with active AS, we show that BME rather than chronic changes is associated with osteoblastic activity, while the combination of BME and FD showed the highest 18F-F uptake. The use of PET/MRI in prediction of future syndesmophyte formation in AS needs further exploration in prospective studies.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".