Abstract 95: Longitudinal In Vivo Quantification of Infarct Size and Cardiac Function in a Murine Model of Myocardial Infarction using Novel Compact High-Performance MRI
Bibliographic record
Abstract
Intro: Delayed Enhancement Imaging (DEI) characterizes MI and predicts therapeutic efficacy following coronary revascularization, stem cell transplantation, or other procedures. Typically gadolinium-based (Gd) contrast agents are injected intravenously and accumulate in the lesion, differentiating between normal and diseased myocardium. Traditionally, DEI has been explored using superconducting high-field MRI. Using a novel compact MRI at 1 Tesla, there is increased sensitivity to Gd-based contrast agents compared with higher-field MRI systems. Hypothesis: In this study, DEI on a compact MRI system was employed with spatial intensity analysis to measure infarct size. Tagged cine MRI assessed myocardial strain using the HARP method. Post-mortem histology of Masson Trichrome staining estimated infarct size. Correlation analysis determined relationships between infarct size measured via DEI and histology. Methods: C57BL/6 MI mice had ligation of the left anterior descending artery. Four sham control and five MI mice we imaged using compact MRI (ICON compact MRI, Billerica, MA) and monitored longitudinally over 21 days for infarct progression and cardiac function in vivo. DE imaging was performed 10-20 minutes post injection of 2 μL Gd contrast agent (ProHance, 0.5 mmol/ml). Images were acquired in short axis, 1 mm superior to the apex. Post-processing analysis (pcVirtue, Diagnosoft, Morrisville, NC) measured cardiac function and infarct size. Results and Conclusions: Analyses of DEI data indicate an average infarct size of 24.85 +/- 15.09 % in the left ventricle. One week after MI induction, a much lower EF was observed in MI mice with respect to control (35.3 +/- 7.567% vs. 67.3 +/- 1.6 %), with a slight recovery of cardiac function in MI mice by week 3 (EF = 45.5 +/- 3.1%). Strain analysis also indicated significantly lower average peak strain in MI vs control mice (6.9 +/- 4.3 vs. 21.5 +/- 0.4 %). Preliminary results demonstrate successful monitoring of cardiac function while performing DEI to visualize and quantify MI at 1 Tesla and leverage the benefits of the increased sensitivity of Gd-based contrast imaging with novel compact MRI. Such imaging and analysis techniques could be used to test efficacy of multiple therapeutic interventions.
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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 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".