Mismatched perfusion defect on V/Q scan associated with PAPVC
Bibliographic record
Abstract
1252 Learning Objectives 1. Present a case of V/Q scan findings of absent perfusion in the right upper lobe in a young adult with history of repaired ASD and PAPVC. 2. Review types of PAPVC and possible complications leading to perfusion defects. 3. Provide a list of common and uncommon differential diagnosis of mismatched perfusion defects on V/Q scan. The presence of partial anomalous pulmonary venous connection (PAPVC) is probably under diagnosed as most patients are asymptomatic. Depending on the severity of the condition, definitive treatment for PAPVC is surgical repair, which may lead to complications such as baffled obstruction. In this poster we present an incidental finding of a mismatched perfusion defect with normal ventilation on V/Q scan in a patient with history of PAPVC. The patient is a 31 year old female 14 weeks pregnant who presented with sudden onset of left sided pleuritic chest pain. Chest X-ray is normal. A V/Q scan shows a mismatched perfusion defect involving the entire right upper lobe. On the follow up chest CT, no identifiable venous drainage of the right upper lobe to the left atrium is identified. The heart is normal in size.The patient has a history of ASD and PAPVC, which was surgically repaired 10 years prior to the V/Q scan, with the right upper pulmonary vein sacrificed. The mechanism of perfusion defect will be discussed. The most common form of PAPVC is one in which a right upper pulmonary vein connects to the right atrium or the superior vena cava. This form is almost always associated with a sinus venosus type of ASD. Other types of PAPVC will be discussed. The types and the seririty of PAPVC may have varied findings on V/Q scan. A V/Q scan is primarily used to evaluate pulmonary embolism. The diagnosis is based on mismatched perfusion defects, which could also be seen with other causes, including the uncommon cause presented in this poster. Knowledge of common and uncommon causes of mismatched perfusion defects is important to trainees in nuclear medicine and radiology. The differential for mismatched perfusion defects on V/Q scan will be presented in this poster.
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.006 | 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".