Diagnostic Accuracy of Single-Photon Emission Tomography Ventilation/Perfusion Lung Scan in the Diagnosis of Pulmonary Embolism

Background Planar ventilation/perfusion ( ) lung scintigraphy is a validated tool for the diagnosis of pulmonary embolism (PE). Nevertheless, given the high rate of nonconclusive , further investigation is often necessary. single-photon emission CT (SPECT) scan could improve performance, but sparse data are available on its accuracy. This study assessed the diagnostic performance of SPECT scan in a cohort of consecutive patients with suspected PE. Methods Three hundred twenty-one consecutive patients with a clinical suspicion of PE were prospectively included. Patients suspected of having PE were managed according to a reference diagnostic strategy validated by a 3-month follow-up. In addition to the reference strategy, patients had a SPECT scan, the results of which were compared with the initial work-up results. Results Prevalence of PE was 0 of 41 (0%; 95% CI, 0%–9%), six of 134 (4%; 95% CI, 2%–9%), 15 of 36 (42%; 95% CI, 27%–58%), and 28 of 32 (88%; 95% CI, 72%–95%) in the normal, low, intermediate, and high SPECT scan probability groups, respectively. The combination of SPECT scan with clinical probability was diagnostic in 88% of patients. Conclusions SPECT scan results show satisfactory accuracy for PE diagnosis. Validation of dedicated interpretation criteria is required, followed by outcome studies that use SPECT scan as part of a diagnostic strategy to rule out PE. Trial registry ClinicalTrials.gov ; No.: NCT01183026; URL: www.clinicaltrials.gov