Abstract 4141861: Detecting Acute Ischemia Prior to Troponin-I Rise Using Hyper-Acute Native T1 Mapping with Ultrastructural Tissue Validation: Implications for Rapid Diagnosis of Non-ST-Elevation Myocardial Infarction
Bibliographic record
Abstract
Background and Hypothesis: Early detection of acute ischemia in non-ST-elevation MI (NSTEMI+) patients is crucial for timely treatment. Traditional biomarkers like high sensitivity cardiac troponin-I level [hs-cTnI] can take hours after myocardial injury to rise in NSTEMI+ patients and potentially delay diagnosis and treatment. We hypothesized that hyper-acute native T1 mapping with cardiac MRI (CMR) can rapidly identify ongoing ischemia. We studied this in canine models of ischemia and then in patients suspected of NSTEMI+. Methods: We performed LAD coronary artery ligation inside a CMR system to induce no-flow ischemia in a canine model (n=18) and performed repeat T1 and T2 mapping every 5 min. We also biopsied myocardial tissue at baseline and at defined time points from ischemic and remote areas. We used transmission electron microscopy (TEM) to analyze cardiac ultrastructure. Patients suspected of NSTEMI+ (n=16) underwent native cine, T1, and T2 CMR 3T. Results: T1 values increased significantly from 1182±51ms (baseline) to 1265±56ms (5 to 10 min after onset of ischemia), p<0.05; and continue to rise through 90 min (1327±56ms), while T2 values showed no significant changes over the first 90 min. TEM showed that the mitochondrial cristae density in ischemic zones was significantly decreased: 100±9.8%(baseline) vs 54±4.4% (5 min of ischemia), p<0.01, and decline to 40.6±9.8% by 90 min. After 5 min of ischemia, both mitochondrial width and circuity index showed no difference compared to baseline, but both paraments increased significantly: (a) mitochondrial width: 990.4±118.6nm (15 min of ischemia) vs 577±61nm (baseline), p<0.01; (b) circuity index: 0.87±0.04 (15 min of ischemia) vs 0.8±0.04 (baseline), p<0.01, and continued to rise and persist at high levels at 90 min: 1091±148 nm (mitochondrial width) and 0.94±0.01 (circuity index), respectively. Cristae number was significantly reduced 13.8±2.7 (baseline) vs 24.4±2.9 (5 min of ischemia), p<0.01, and remained low and reduced to 7.6±1.8 by 90 min. ΔT1 value in patients were significantly higher in NSTEMI+ than in NSTEMI- (11.51±3.7% vs 2.06±1.7%, p<0.0001), while [hs-cTnI] levels from NSTEMI+ gradually increased over time and were only significantly higher than NSTEMI-, several hours after CMR and peaked at 24 h (12.6±7.3% (24 h) vs 0.03±0.02% (baseline), p<0.05). Conclusions: Hyper-acute native T1 mapping has the potential to rapidly identify ongoing ischemia even in the absence of troponin-I rise.
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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 | 0.000 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".