Construction and evaluation of a switch‐tuned <sup>13</sup>C ‐ <sup>1</sup>H birdcage radiofrequency coil for imaging the metabolism of hyperpolarized <sup>13</sup>C‐enriched compounds
Bibliographic record
Abstract
PURPOSE: To construct a switch-tuned (13) C - (1) H birdcage radiofrequency (RF) coil system capable of metabolic imaging of hyperpolarized (13) C-enriched metabolic probes for co-registration with MRI morphology using protons. MATERIALS AND METHODS: The switch-tuned coil was constructed using PIN diodes for rapid switching of the resonant frequency of the coil. Identical, single-tuned, (1) H and (13) C birdcage RF coils have also been constructed for comparison of imaging performance. A (13) C receive-only surface RF coil has been integrated with the switch-tuned coil for transmit-only, receive-only operation (TORO) to increase local (13) C signal for improved signal-to-noise ratio (SNR). RESULTS: The SNR achieved with the switch-tuned coil in transmit/receive mode was 87% that of the single-tuned (1) H coil. For (13) C imaging, the SNR for the switch-tuned coil was 55% that of the single-tuned (13) C coil. TORO operation of the switch-tuned coil with the surface coil increased SNR for by a factor of 4.2 over transmit/receive operation of the switch-tuned coil alone. CONCLUSION: A surface coil can be integrated with a switch-tuned (13) C - (1) H coil for (13) C TORO operation producing improved SNR. In vivo metabolic imaging of [1-(13) C]pyruvate in a rat model of glioma is demonstrated using TORO operation, which is co-registered with (1) H-imaged anatomy.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".