Abstract 12052: Myocardial Extracellular Matrix Expansion Detected With Cardiac MRI: A Biomarker of Cardiomyopathic Disease in Duchenne Muscular Dystrophy
Bibliographic record
Abstract
Introduction: Duchenne muscular dystrophy (DMD) cardiomyopathy is a progressive disease for which standard heart failure therapies have limited efficacy. Disease-specific therapies are needed that can be initiated before irreversible myocardial damage ensues. In order to evaluate therapeutic efficacy, surrogate endpoints other than ejection fraction must be found. Hypothesis: The study hypothesis is that T1 and extracellular volume fraction (ECV) mapping using cardiac magnetic resonance imaging (CMR) can detect diffuse extracellular matrix expansion in DMD patients with normal left ventricular ejection fraction (LVEF) and without late gadolinium enhancement (LGE). Methods: 28 DMD and 11 healthy control participants were prospectively enrolled. CMR using a modified Look-Locker (MOLLI) sequence was performed before and after contrast administration. T1 and ECV maps of the mid left ventricular myocardium were generated and regions of interest were contoured using the standard 6-segment AHA model. Global and segmental values were compared between DMD and controls using a Wilcoxon rank-sum test. Results: DMD participants had significantly higher mean native T1 compared with controls (1045ms vs 988ms, p<0.001) (Fig 1A). DMD participants with normal LVEF and without evidence of LGE also demonstrated elevated mean native T1 (1036ms vs 988ms, p<0.001, and 1039ms vs 988ms, p=0.001) (Fig 1C, 1E). Mean post-contrast T1 values were not significantly different between DMD participants and controls. DMD participants had a significantly greater mean ECV than controls (0.31 vs 0.24, p<0.001), even in the settings of normal LVEF (0.29 vs 0.24, p<0.001) and negative LGE (0.30 vs 0.24, p<0.001) (Fig 1B, 1D, 1F). Conclusions: DMD participants have elevated native T1 and ECV in left ventricular myocardium, even in the setting of normal LVEF and in the absence of LGE. T1 and ECV mapping in DMD have potential to serve as surrogate cardiomyopathy outcome measures for clinical trials.
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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) | 0.003 | 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".