Automated contouring of non-contrast echocardiograms result in similar estimates of left ventricular function to manually contoured contrast-enhanced images in chemotherapy patients
Bibliographic record
Abstract
Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Ultromics Ltd Introduction Transthoracic echocardiography (TTE) assessment of left ventricular (LV) function has a central role in early detection and treatment of cancer-therapy related cardiac dysfunction (CTRCD). Contrast TTE is recommended to aid accurate and reproducible LV contouring , but contrast agents are underused and high variability remains. Using machine learning (ML) to automatically contour the LV reduces variability, and may provide comparable clinical benefit to contrast-enhanced TTE. Purpose Retrospective single site study evaluating agreement between LV volumes and function from manually contoured contrast-enhanced TTE and automated contouring of non-contrast enhanced images. Methods Adults at risk of developing CTRCD who underwent TTE were recruited. LV volumes (end-diastolic and systolic; EDV and ESV, respectively) and function (ejection fraction; EF) were measured from contrast-enhanced images using manual contouring (MAN-CONT), and non-contrast enhanced images using automation (AUTO-NON). Method comparisons were summarised based on: (i) statistical equivalence (two one-sided t-tests), (ii) systematic difference between methods, via root mean-squared error (RMSE; Deming regression), and (iii) average bias (Bland-Altman). Statistical equivalence bounds were conservatively determined from reproducibility estimates in a similar cohort (EDV, 20 mL; ESV, 15 mL; EF, 5%; REF1), and used to interpret RMSE and bias. Results The cohort comprised of patients undergoing treatment for breast cancer, lymphoma, and myeloma. Similar body mass indices were seen between groups (median [IQR]: 26.5 [6.7] kg/m2; Kruskall-Wallace test, p = 0.320), but breast cancer patients were younger (55.0 [14.5], 58.5 [23], 60 [9], respectively; p = 0.034). For estimates of LV volumes and function, statistical equivalence, RMSE, and bias are presented in Table1. Average estimates (mean [SD]) of EDV, ESV, and EF were 121 [33] vs. 112 [33] mL, 50 [23] vs. 44 [19] mL, and 60 [9] vs. 61 [8]%, for MAN-CON and AUTO-NON respectively. Comparing between MAN-CON and AUTO-NON in breast cancer patients, all variables were statistically equivalent (Figure1), and while bias was lower than equivalence bounds, RMSE was only lower for EDV and ESV, not EF. For lymphoma patients, estimates of EDV were statistically equivalent, but not EF and ESV. Bias was lower than equivalence bounds for all variables, whereas RMSE was lower for ESV, but not EDV or EF. For myeloma patients, estimates of ESV and EF were statistically equivalent, but not EDV. While bias was lower than equivalence bounds for all variables, RMSE was not lower for any variable. Conclusions: Estimates of LV function from automated contouring of non-contrast TTE are similar to contrast-enhanced TTE (manually contoured), despite poorer image quality. Automated contouring using ML reduces variability, therefore increasing TTE sensitivity, which is critical when clinical management relies on accurate assessment of LV function. Abstract Table1 Abstract Figure1
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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 | 0.002 | 0.016 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".