Sci—Sat AM: Brachy — 12: Resolving the olefinic lipid resonance from water in proton magnetic resonance spectra of vertebral bone marrow at 3 T
Bibliographic record
Abstract
Proton magnetic resonance spectroscopy (MRS) of vertebral lipids has been shown to be relevant in the study of cancer. The olefinic resonance (≈ 5.4 ppm) yields a measure of lipid unsaturation. However, its measurement with standard short echo time (TE) MRS sequences is difficult due to the large overlapping water signal. The purpose of this work is to optimize the TE of a PRESS (Point RESolved Spectroscopy) sequence to measure the olefinic resonance from spinal bone marrow with minimal losses due to J‐coupling and minimal contamination from water at 3 T, a field strength becoming more common in the clinic. Experiments were conducted on nine oils and on L4 vertebral bone marrow in vivo at 3 T. The methyléne (or methyl + méthyléne), and olefinic resonances were measured with PRESS using multiple TEs. The effects of J‐coupling evolution of the olefinic protons appeared to be minimal when TE = 200 ms. The TE = 200 ms olefinic/methylene peak area ratios calculated for each oil correlated well with ratios deduced from oil compositions in the literature (R2 = 0.92). The TE = 200 ms PRESS spectra obtained from vertebra of four volunteers showed negligible contribution from water to the olefinic resonance, thereby enabling the olefinic peak area to be quantified more accurately. The results of this work demonstrate that a PRESS sequence with TE = 200 ms is suitable for measuring relative levels of lipid unsaturation and for resolving the olefinic resonance from contaminating water signal in spinal bone marrow.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.165 | 0.061 |
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".