title: Lung scintigraphy and helical computed tomography for the diagnosis of pulmonary embolism: a meta-analysis.
abstract: To assess the diagnostic value of lung scintigraphy and helical computed tomography (hCT) in patients with suspected pulmonary embolism (PE), all English-language articles that described lung scintigraphy and hCT in patients with suspected PE were retrieved. Articles were assessed for strength of methodology, based on nine a priori-defined criteria. Parameters of diagnostic accuracy and results of management studies were calculated and evaluated. Lung scintigraphy is diagnostic in approximately 50% of patients with suspected PE. A normal perfusion scan has a chance of recurrent PE in two of 693 patients (0.3%; 95% CI: 0.2-0.4%; fatal in 0.15%). A high-probability lung scan is correlated with angiographically proven PE in 308 of 350 patients (88%; 95% CI: 84-91%). Pulmonary embolism was proven in 385 of 1529 patients (25%; 95% CI: 24-28%) with a nondiagnostic lung scan. Helical CT studies were compared with angiography and lung scintigraphy in 1171 patients, with a prevalence of PE of 39%. The sensitivity and specificity of hCT was 283/320 (88%; 95% CI: 83-91%) and 374/408 (92%; 95% CI: 89-94%), respectively. Only one prospective management study using hCT was available. In patients in whom anticoagulants were withheld based on a normal hCT study, recurrent thromboembolic events occurred in six of 109 patients (5.5%; 95% CI: 2-12%), with one fatality (1%; 95% CI: 0.02-4.3%). Lung scintigraphy is evaluated extensively and yields a diagnostic result in 50% of patients. Helical CT has similar positive predictive value to a high-probability lung scan. However, the exact role of hCT in the management of patients with suspected PE needs to be determined in prospective studies.
authors: Section of Academic Radiology, Royal Hallamshire Hospital, Sheffield, UK.
authors: E J
authors: EJ
authors: van Beek
authors: E M
authors: EM
authors: Brouwers
authors: B
authors: B
authors: Song
authors: A H
authors: AH
authors: Bongaerts
authors: M
authors: M
authors: Oudkerk
mesh_terms: D000792:Angiography / Q000592:standards / Q000706:statistics & numerical data; D016001:Confidence Intervals; D006801:Humans; D011655:Pulmonary Embolism / Q000175:diagnosis*; D011877:Radionuclide Imaging / Q000592:standards / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity; D015898:Tomography Scanners, X-Ray Computed / Q000592:standards / Q000706:statistics & numerical data; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000592:standards* / Q000706:statistics & numerical data