An anthropomorphic prostatic urinary tract phantom for Doppler-based assessment of voiding dysfunction
Bibliographic record
Abstract
Direct assessment of urinary flow dynamics during voiding is challenging to perform in vivo. New Doppler ultrasound techniques are being developed for this purpose, but their performance needs to be systematically evaluated using phantoms. Here, we present a new design protocol to fabricate a urinary tract phantom with realistic anatomical, mechanical and urodynamic properties. In this protocol, computer-aided design of the urethra geometry was first drafted and it was physically built using 3-D printing. Subsequently, the flexible urinary tract tube was fabricated from polyvinyl alcohol cryogel (Young’s modulus: 26.6 kPa), while an agar–gelatin mixture (Young's modulus: 17.4 kPa) forms the surrounding tissue mimic. Finally, the urethra phantom was connected to a flow circuit that simulates voiding. Deformable phantoms were devised for a normal urethra and a diseased urethra with benign prostatic hyperplasia (BPH) obstruction. The phantoms’ morphologies were measured with ultrasound imaging and their flow profiles were assessed using Doppler ultrasound. During voiding, short-axis lumen diameter at the obstruction of the BPH-featured phantom was significantly smaller (0.91 vs 2.49 mm) while the maximum flow velocity was higher (59.3 vs 22.7 cm/s) compared to those of the normal urethra. These fabricated phantoms were effective in simulating urethra deformation resulting from urine passage and may promote the development of new Doppler-based urodynamic measurement techniques.
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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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".