Optimizing U-Net to Segment Left Ventricle from Magnetic Resonance Imaging
Bibliographic record
Abstract
Left ventricle segmentation is an important medical imaging task to measure several diagnostic parameters related to the heart such as ejection fraction and stroke volume. Recently, convolutional neural networks (CNN) have shown great potential in achieving state-of-the-art segmentation results for such applications. However, most of the existing research is focusing on building complicated variations of the neural networks with modest changes to their performance. In this study, the popular U-Net architecture is optimized by analyzing its behaviour once fully trained from which one can simplify its architecture by fixing layers weights or eliminating some of them completely. For instance, by performing a Fourier analysis of the convolution at each layer, we were able to discover that some early layers can be approximated by simple uniform filters. Furthermore, in a separate experiment by removing the middle layers of the U-Net one can reduce the number of U-Net parameters from 31 million to 0.5 million weights without compromising its performance. The experimental evaluations show that the new optimized U-Net achieves 0.93 for the Dice score in comparison to manual ground truth.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".