First in‐human evaluation of [<scp>1‐<sup>13</sup>C</scp>]pyruvate in <scp>D<sub>2</sub>O</scp> for hyperpolarized <scp>MRI</scp> of the brain: A safety and feasibility study
Bibliographic record
Abstract
Abstract Purpose To investigate the safety and value of hyperpolarized (HP) MRI of [1‐ 13 C]pyruvate in healthy volunteers using deuterium oxide (D 2 O) as a solvent. Methods Healthy volunteers ( n = 5), were injected with HP [1‐ 13 C]pyruvate dissolved in D 2 O and imaged with a metabolite‐specific 3D dual‐echo dynamic EPI sequence at 3T at one site (Site 1). Volunteers were monitored following the procedure to assess safety. Image characteristics, including SNR, were compared to data acquired in a separate cohort using water as a solvent ( n = 5) at another site (Site 2). The apparent spin–lattice relaxation time (T 1 ) of [1‐ 13 C]pyruvate was determined both in vitro and in vivo from a mono‐exponential fit to the image intensity at each time point of our dynamic data. Results All volunteers completed the study safely and reported no adverse effects. The use of D 2 O increased the T 1 of [1‐ 13 C]pyruvate from 66.5 ± 1.6 s to 92.1 ± 5.1 s in vitro, which resulted in an increase in signal by a factor of 1.46 ± 0.03 at the time of injection (90 s after dissolution). The use of D 2 O also increased the apparent relaxation time of [1‐ 13 C]pyruvate by a factor of 1.4 ± 0.2 in vivo. After adjusting for inter‐site SNR differences, the use of D 2 O was shown to increase image SNR by a factor of 2.6 ± 0.2 in humans. Conclusions HP [1‐ 13 C]pyruvate in D 2 O is safe for human imaging and provides an increase in T 1 and SNR that may improve image quality.
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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 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| 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".