title: Diagnosis of pulmonary embolism: ventilation perfusion scintigraphy versus helical computed tomography pulmonary angiography.
abstract: The present study compared the accuracy of ventilation perfusion scintigraphy (VQS) and CT pulmonary angiography (CTPA) for the diagnosis of pulmonary embolism. This was a prospective observational study of 112 patients with suspected pulmonary embolism (PE) who could be studied with both investigations within 24 h. Results were compared to final diagnosis at completion of 6-month follow up, using receiver operating characteristic (ROC) analysis. Pulmonary embolism was diagnosed in 27 referred patients (24%). The sensitivity and specificity of VQS and CTPA were similar to that reported from the literature. A normal VQ scan had the highest negative predictive value (100%), while a high-probability VQ scan had the highest positive predictive value (92%). There was no overall difference (area under the ROC curve (AUC)) between VQS (AUC (95% CI) = 0.82 (0.75,0.89)) and CTPA (AUC = 0.88 (0.81,0.94)) for the diagnosis of PE. Among patients with abnormal chest X-rays, CTPA (AUC 0.90 (0.83,0.97)) appeared somewhat better than VQS (AUC 0.78 (0.68,0.88)) but this difference did not reach statistical significance. In this instance, CTPA is at least as accurate as VQS and may provide an opportunity to make alternative diagnoses.
authors.affiliation: Department of Nuclear Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia. william.macdonald@health.wa.gov.au
authors.forename: W B G
authors.initials: WB
authors.lastname: Macdonald
authors.forename: A P
authors.initials: AP
authors.lastname: Patrikeos
authors.forename: R I
authors.initials: RI
authors.lastname: Thompson
authors.forename: B D
authors.initials: BD
authors.lastname: Adler
authors.forename: A A
authors.initials: AA
authors.lastname: van der Schaaf
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D016009:Chi-Square Distribution; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D012372:ROC Curve; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013668:Technetium Tc 99m Aggregated Albumin; D036542:Tomography, Spiral Computed; D014692:Ventilation-Perfusion Ratio
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D007472:Iohexol