title: Diagnostic evaluation of planar and tomographic ventilation/perfusion lung images in patients with suspected pulmonary emboli.
abstract: Planar lung ventilation/perfusion scintigraphy (V/P(PLANAR)) is a standard method for diagnosis of pulmonary embolism (PE). The goals of this study were to test whether the diagnostic information of ventilation/perfusion tomography (V/P(SPET)) applied in clinical routine might enhance information compared with V/P(PLANAR) and to streamline data processing for the demands of clinical routine. This prospective study includes 53 patients suspected for PE referred for lung scintigraphy. After inhalation of (99m)Tc-DTPA planar ventilation imaging was followed by tomography, using a dual-head gamma camera. (99m)Tc-MAA was injected i.v. for perfusion tomography followed by planar imaging. Patients were examined in supine position, unchanged during V/P tomography. Two reviewers evaluated V/P(PLANAR) and V/P(SPET) images separately and randomly. Mismatch points were calculated on the basis of extension of perfusion defects with preserved ventilation. Patients were followed up clinically for at least 6 months. With V/P(SPET) the number of patients with PE was higher and 53% more mismatch points were found. In V/P(SPET) interobserver variation was less compared with V/P(PLANAR). Ancillary findings were observed by both techniques in half of the patients but more precisely interpreted with V/P(SPET). V/P(SPET) shows more and better delineated mismatch defects, improved quantification and less interobserver variation compared with V/P(PLANAR). V/P(SPET) is amenable to implementation for clinical routine and suitable even when there is demand for a high patient throughput.
authors.affiliation: Center for Medical Imaging and Clinical Physiology, University Hospital Lund, 221-85 Lund, Sweden. marika.bajc@klinfys.lu.se
authors.forename: Marika
authors.initials: M
authors.lastname: Bajc
authors.forename: Carl-Gustav
authors.initials: CG
authors.lastname: Olsson
authors.forename: Berit
authors.initials: B
authors.lastname: Olsson
authors.forename: John
authors.initials: J
authors.lastname: Palmer
authors.forename: Björn
authors.initials: B
authors.lastname: Jonson
mesh_terms: D000280:Administration, Inhalation; D006801:Humans; D007275:Injections, Intravenous; D008168:Lung / Q000000981:diagnostic imaging*; D015588:Observer Variation; D049268:Positron-Emission Tomography / Q000379:methods; D011655:Pulmonary Embolism / Q000175:diagnosis / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013668:Technetium Tc 99m Aggregated Albumin / Q000008:administration & dosage; D016284:Technetium Tc 99m Pentetate / Q000008:administration & dosage; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014692:Ventilation-Perfusion Ratio
chemical_list: D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D016284:Technetium Tc 99m Pentetate