title: Acute pulmonary embolism detection with ventilation/perfusion SPECT combined with full dose CT: What is the best option?
abstract: OBJECTIVE
  To compare diagnostic accuracy of Ventilation/Perfusion (V/P) single-photon emission computed tomography (SPECT) combined with simultaneous full-dose CT with a hybrid SPECT/CT scanner versus planar ventilation/perfusion (V/P) SPECT and CT angiography (CTA) in patients suspected with acute pulmonary embolism (PE).
  
  
  METHODS
  Between 2009 and 2011, consecutive patients suspected of acute PE were referred for V/P SPECT/CT (reviewed board approved study). A contrast agent was administered to patients who had no contraindications. Non-contrast V/P SPECT/CT was performed on the remaining patients. All patients were followed-up for at least 3 months.
  
  
  RESULTS
  A total of 314 patients were available during the study period, with the diagnosis of PE confirmed in 70 (22.29%) of them. The overall population sensitivity and specificity was 90.91% and 92.44%, respectively for V/P SPECT, 80% and 99.15%, respectively, for CTA, and 95.52% and 97.08% for V/P SPECT/CT. SPECT/CT performed better than V/P SPECT (AUC differences=0.0419, P=0.0043, 95% CI; 0.0131-0.0706) and CTA (AUC differences=0.0681, P=0.0208, 95% CI; 0.0103-0.1259)). Comparing imaging modalities when contrast agent could be administered, sensitivity and specificity increased and V/P SPECT/CT was significantly better than CTA (AUC differences=0.0681, P=0.0208, 95% CI; 0.0103-0.1259) and V/P SPECT (AUC differences=0.0659, P=0.0052, 95% CI; 0.0197-0.1121). In case of non-contrast enhancement, there was non-significant increase of specificity. Secondary findings on CT impacted patient management in 14.65% of cases.
  
  
  CONCLUSIONS
  Our study shows that combined V/P SPECT/CT scanning has a higher diagnostic accuracy for detecting acute PE than V/P SPECT and CTA alone. When feasible, V/P SPECT/CT with contrast enhancement is the best option.
authors.affiliation: Department of Nuclear Medicine (ICS-IDI), Hospital Universitari Germans Trias i Pujol, Badalona, Spain. Electronic address: mamila_13@hotmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Milà
authors.affiliation: Department of Radiology, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Bechini
authors.affiliation: Applied Statistics Service, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Vázquez
authors.affiliation: Department of Nuclear Medicine (ICS-IDI), Hospital Universitari Germans Trias i Pujol, Badalona, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Vallejos
authors.affiliation: Department of Radiology, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Tenesa
authors.affiliation: Applied Statistics Service, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Espinal
authors.affiliation: Department of Nuclear Medicine (ICS-IDI), Hospital Universitari Germans Trias i Pujol, Badalona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Fraile
authors.affiliation: Department of Internal Medicine, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Monreal
mesh_terms: D000208:Acute Disease; D000368:Aged; D000072226:Computed Tomography Angiography; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014692:Ventilation-Perfusion Ratio
keywords: Angiografía por TC; CT angiography; Contraste yodado; Iodinated contrast; Pulmonary embolism; SPECT de V/P; SPECT/CT; SPECT/TC; Tromboembolismo pulmonar; V/P SPECT