Implementation of a biparametric prostate MRI protocol with a recall system for intravenous contrast: an analysis of recall rates and comparison of PI-RADS category distribution
Bibliographic record
Abstract
Abstract ObjectivesThe prostate magnetic resonance imaging (MRI) protocol changed from a contrast multiparametric MRI (mp-MRI) to a non-contrast biparametric (bp-MRI) protocol at a single centre. This study describes the recall rate, median time to recall, and PI-RADS distribution pre-/post-implementation.MethodsThis retrospective descriptive study involved a consecutive sample of all 3 Tesla (3T) prostate bp-MRIs following the protocol change (01April2023-23May2024) to determine the proportion of bp-MRIs recalled, the indications for recall, and the median time until recall MRI (Part 1). A subset of these prostate MRIs was compared to a consecutive sample immediately prior to the change in protocol to compare the distribution of PI-RADS categories (Part 2). The distribution of MRI reporting frequency by radiologists was compared pre-/post-implementation (Part 2). Inclusion criteria: 3T bp-MRI protocol, out-patient, male, and ≥ 18 years of age.ResultsA total of 554 prostate bp-MRIs took place during the study period, 547 (96.8%) were included. Of the 547 subjects, 36 (6.6%) were recalled for intravenous (IV) contrast. Most recalls were for PI-RADS 3 reassessment (33/36, 91.7%). PI-RADS categories were upgraded in 19/36 (52.8%) subjects. The median time between initial and recall MRI was 35 days. There was no statistically significant difference in the distribution of PI-RADS categories before (n = 225) and after (n = 225) implementation of the bp-MRI protocol (X2, p = 0.09). There was no statistically significant difference in the distribution of MRI reporting frequency by radiologists pre-/post-implementation (X2, p = 0.06).ConclusionA small proportion (6.6%) of bp-MRI subjects were recalled for contrast reassessment and the majority of those (52.8%) received PI-RADS category upgrade. There was no statistically significant difference in the distribution of PI-RADS categories following implementation of the bp-MRI protocol. Implementation of a bp-MRI protocol at a single centre reduced patient exposure to IV contrast while not changing PI-RADS distribution.
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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 | 0.011 | 0.040 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".