Quantified T <sub>1</sub> As An Adjunct To Apparent Diffusion Coefficient For Early Infarct Detection: A High-Field Magnetic Resonance Study in a Rat Stroke Model
Bibliographic record
Abstract
BACKGROUND: Thrombolytic treatment for acute stroke has focused attention on accurate identification of injured vs. salvageable brain tissue, particularly if reperfusion occurs. However, our knowledge of differences in acute magnetic resonance imaging changes between transient and permanent ischemia and how they reflect permanently damaged tissue remain incomplete. AIMS AND/OR HYPOTHESIS: Magnetic resonance imaging characteristics vary widely following ischemia and, at acute times, T1, T2 or apparent diffusion coefficient quantification may differentiate viable tissue from that destined to infarct. METHODS: High-resolution magnetic resonance imaging was performed at 9.4 T following permanent or transient (90 min) middle cerebral artery occlusion in spontaneously hypertensive male rats or Wistar rats. Within 30 min, quantified maps of the apparent diffusion coefficient, T1, and T2 were performed and measures determined for sequences in the infarct and compared with that in the contralateral region. Lesion area for each magnetic resonance imaging sequence (T1, T2, apparent diffusion coefficient, and perfusion maps) was delineated for different time points using quantitative threshold measures and compared with final histological damage. RESULTS: Early extensive changes in T1 following both transient and permanent middle cerebral artery occlusion provided a sensitive early indicator of the final infarct area. Following reperfusion, small but measurable early T2 changes indicative of early development of vasogenic edema occurred in the transient but not permanent groups. In transient middle cerebral artery occlusion, at 70 min apparent diffusion coefficient decreased (P<0.001) and then pseudonormalized at 150 min. In permanent middle cerebral artery occlusion, apparent diffusion coefficient declined over time. Lesion area detected using T1 maps exceeded that with T2 and apparent diffusion coefficient at 70 and 150 min in both groups (P<0.001). CONCLUSIONS: The results indicate that, independent of reperfusion, quantified T1 is superior for detecting early ischemic changes that are not necessarily detected with T2 or apparent diffusion coefficient.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".