Time trend analysis of pulmonary embolism diagnosis with single-photon emission computed tomography ventilation/perfusion imaging
Bibliographic record
Abstract
OBJECTIVE: Following the implementation of single-photon emission computed tomography ventilation/perfusion (SPECT V/Q) in our department, we previously carried out an observational study over the period 2011-2013 that showed the safety of SPECT V/Q to rule out pulmonary embolism (PE). However, PE prevalence (28%) was high compared with some studies. Our hypothesis was that the use of SPECT V/Q may be responsible for an overdiagnosis of PE, especially at the implementation phase of the test. The aim was to carry out a time trend analysis of the evolution over the years of PE diagnosis with SPECT V/Q. PATIENTS AND METHODS: To evaluate the time trend of SPECT V/Q results, the conclusions of all SPECT V/Q scans performed for a suspected acute PE in our department from April 2011 to December 2016 were collected. To confirm the safety of a diagnostic management on the basis of SPECT V/Q to rule out PE, a retrospective observational study of the outcome of patients assessed with SPECT V/Q for suspected acute PE was carried out during the period 2014-2016. SPECT V/Q was interpreted using a diagnostic cutoff of one segmental or two subsegmental mismatches. The final diagnostic conclusion was established by the physician responsible for patient care. The safety of SPECT V/Q was assessed by monitoring the risk of thromboembolic events during the 3-month follow-up period in patients left untreated on the basis of a negative SPECT V/Q. RESULTS: Over the period 2011-2016, an average 16% (95% confidence interval: 10-22%) annual reduction in the proportion of positive SPECT V/Q results was observed. The percentage of positive SPECT V/Q results was 25.3% over the period 2011-2013 compared with 16.3% in 2014-2016 (P<0.0001). Out of the 696 patients analyzed over the period 2014-2016, the SPECT V/Q was positive, indeterminate, and negative in 118, 3, and 575 patients, respectively. The 3-month thromboembolic risk in patients in whom PE was deemed absent according to the SPECT V/Q was 3/543=0.55% (95% confidence interval 0.19-1.61). CONCLUSION: A continuous decrease in the annual proportion of positive SPECT V/Q results was mainly observed while maintaining the safety of the test to rule out PE. Explanatory factors include the introduction of a combined SPECT/CT scan, increased experience and familiarity with the test, and an increased awareness of the risks and consequences of overdiagnosing PE.
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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 | 0.003 | 0.010 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".