Gadolinium‐free extracellular MR contrast agent for tumor imaging
Bibliographic record
Abstract
PURPOSE: To evaluate a new formulation of manganese porphyrin as a potential gadolinium (Gd)-free extracellular magnetic resonance imaging (MRI) contrast agent for dynamic contrast-enhanced (DCE) MRI of tumors. MATERIALS AND METHODS: A previously reported new contrast agent, MnTCP, was evaluated in six female tumor-bearing nude rats. MRI was performed on a 3 T clinical scanner 3 to 4 weeks after inoculation of breast tumor cells in the mammary fat pads. Gd-DTPA was injected intravenously, followed by injection of MnTCP at least 2 hours later (both at 0.05 mmol/kg). T1 relaxation time measurements and DCE-MRI were performed. RESULTS: Enhancement and clearance patterns were visually similar between MnTCP and Gd-DTPA. However, relative R1 increases in all 11 tumors were larger for MnTCP over 60 minutes postcontrast, the difference being significant as late as 20 minutes (R1post /R1pre = 1.42 ± 0.15 for MnTCP vs. 1.20 ± 0.08 for Gd-DTPA, P < 0.05). R1 -related effects for MnTCP were largely reduced after 60 minutes (R1post /R1pre = 1.13 ± 0.07) and completely gone within 24 hours (R1post /R1pre = 0.97 ± 0.06). DCE-MRI revealed a consistently larger (1.5 to over 2-fold) peak enhancement and higher values of the steepest slope, time-to-peak, and AUC60 in all tumors with MnTCP (P < 0.01). CONCLUSION: MnTCP is an alternative to extracellular Gd agents for tumor imaging, offering sensitive detection and rapid renal clearance.
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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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".