Comparison of two ultrasound contrast agents for left ventricular opacification
Bibliographic record
Abstract
Abstract Background Several ultrasound contrast agents have been approved and used for measurement of left ventricular (LV) ejection fraction (EF). However, there has been no direct comparison between these agents. Purpose To compare left ventricular imaging parameters between two widely used ultrasound contrast agents for LV opacification when imaged with a low power contrast specific imaging modality. Methods In this retrospective study of patients undergoing echocardiography during anti-cancer treatment were included who underwent follow-up echocardiograms (3 months) with two different ultrasound contrast agents - Definity® and SonoVue® - if there were only minor changes in the LV ejection fraction (EF) between the studies (< 5%). Qualitative and quantitative analysis of the contrast effect was performed in apical four- and two chamber views (4CV,2CV). For quantitative analysis of the LV opacification, square regions of interest (ROI) were placed in the apical and basal ventricular lumen and the arithmetic mean and standard deviation of pixel intensity within each ROI was recorded throughout the entire loop. Qualitative visual assessment was performed using a visual score to assess the endocardial border delineation, basal attenuation and apical swirling. Results 41 female patients with a mean EF of 61 ± 9% (mean ± standard deviation, SD) fulfilled the inclusion criteria. Both contrast agents provided intensive LV opacification in the basal and apical cavities. The video intensities (mean + standard deviation) in the apical and basal cavities were comparable across both contrast agents in the 2CV apical ROI (219.96 ± 21.42 vs 224.69 ± 20.23), the 2CV basal ROI (114.55 ± 42.02 vs 112.79 ± 42.57), the 4CV apical ROI (228.02 ± 17.80 vs 225.51 ± 20.37), and the 4CV basal ROI (100.05, 41.11 vs 92.84, 42.54). Visual assessment revealed no statistical difference between the contrast agents in terms endocardial delineation. Conclusion In patients with normal LV function both ultrasound contrast agents, no clinically relevant differences were found regarding LV opacification and endocardial border delineation.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".