Clinicians' interpretation of ventilation/perfusion lung scan reports: Where are we today?

Abstract

Background: Clinicians' interpretation of lung scan reports will determine which further management decisions are taken when potentially fatal pulmonary embolism (PE) is suspected.

Objectives: To assess current referring clinicians' interpretation of the terminology used in ventilation/perfusion (V/Q) scan reports, whether this interpretation is affected by experience level, and how it affects clinical management decisions.

Methods: This was a questionnaire-based cross-sectional study. Between September 2020 and May 2021, 300 questionnaires were distributed among clinicians who refer patients for V/Q scans.

Results: Of the 162 clinicians who responded, 94% thought that there is >85% likelihood of PE or definitely PE present when a scan is reported as 'high probability of PE'; 87% interpreted 'low probability of PE' as <10% likelihood of PE or definitely no PE present. Overall, >70% of clinicians across all experience levels correctly interpreted the intended meaning of probability categories according to the Modified Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II criteria. Of the respondents, 77% agreed that clinically significant PE is ruled out by a normal scan. Further investigation for inconclusive findings, features of parenchymal lung disease and cardiomegaly were selected by 72%, 93% and 98% of clinicians, respectively.

Conclusion: The findings of this study regarding high-probability scan results were in line with existing literature on lung scan report interpretation. However, our findings regarding low-probability scan results and negative V/Q scan specificity contrasted with the findings in these articles, suggesting that clinicians are now more familiar with lung scan interpretation guidelines. Experience level did not significantly affect interpretation of reports. Although most clinicians agreed that a negative scan excludes clinically significant PE, two-thirds of them would still subject the patient to further unnecessary investigations to exclude PE.

Study synopsis: What the study adds. Our findings regarding a low-probability ventilation/perfusion (V/Q) scan and the specificity of a negative V/Q scan contrasted with previous articles on lung scan interpretation, suggesting that clinicians are now more familiar with lung scan interpretation guidelines.Implications of the findings. Although most clinicians understood the negative predictive value of a V/Q scan, 20% would still investigate further with computed tomography pulmonary angiography or treat as confirmed pulmonary embolism. Education of clinicians about the negative predictive value of V/Q scans is important to avoid unnecessary radiation or anticoagulation.

Keywords: Pulmonary embolism; clinician’s interpretation; lung scan.

Fig. 1

Interpretation of V/Q scan reported as high probability for PE V/Q = ventilation/perfusion PE = pulmonary embolism

Fig. 2

Interpretation of V/Q scan reported as low probability for PE. V/Q = ventilation/perfusion PE = pulmonary embolism

Fig. 3

Interpretation of V/Q scan reported as high probability for PE, by experience in years. V/Q = ventilation/perfusion PE = pulmonary embolism

Fig. 4

Interpretation of V/Q scan reported as low probability for PE, by experience in years. V/Q = ventilation/perfusion PE = pulmonary embolism

Fig. 5

Normal V/Q scan rules out PE. V/Q = ventilation/perfusion PE = pulmonary embolism