title: Post-test probability for pulmonary embolism after ventilation-perfusion scan assessed by nuclear medicine physicians.
abstract: OBJECTIVE
  The objective of this prospective study was to compare assessments of pre- and post-ventilation-perfusion (V/Q) scan probabilities for pulmonary embolism (PE) by the nuclear medicine physician and the referring physician.
  
  
  METHODS
  Seventy-nine patients (41 females, 38 males, mean age 49 years) referred for V/Q scans over a period of 6 months and suspected of PE were included in the study. The pre-test likelihood was determined independently by a consultant nuclear physician and a referring physician prior to the V/Q scan. The scan was performed according to a standard protocol using 8 view technetium-99m diethylenetriamine pentaacetic acid aerosol ventilation study followed by a technetium-99m macroaggregated albumin perfusion study. The scan was interpreted according to prospective investigation of pulmonary embolism diagnosis criteria. The post-scan probability was calculated. The probability of PE was quoted as low, intermediate and high. Agreement or disagreement in assessing the pre- and post-scan probability was classified according to the degree of difference (no difference: 0; minor difference: 1, and major difference: 2 grades).
  
  
  RESULTS
  The agreement between the nuclear medicine and referring physicians on clinical probability of PE was moderate (63%) before the scan and good (90%) after the scan. The disagreement in assessing the clinical probability between the referring physician and the nuclear medicine physician was predominantly minor. Only 5 and 1% of the disagreement was major in pre-scan and post-scan probabilities, respectively.
  
  
  CONCLUSIONS
  The data show that nuclear medicine physicians can use the assessment of pre-scan clinical likelihood to determine the post-scan probability of PE.
authors.affiliation: Department of Medicine, Faculty of Medicine, Kuwait University, Kuwait. aelgazzar49@hotmail.com
authors.forename: Abdelhamid H
authors.initials: AH
authors.lastname: Elgazzar
authors.forename: Issa
authors.initials: I
authors.lastname: Loutfi
authors.forename: Mona
authors.initials: M
authors.lastname: Baqer
authors.forename: M
authors.initials: M
authors.lastname: Farghali
authors.forename: Mousa
authors.initials: M
authors.lastname: Khadada
authors.forename: Sherif
authors.initials: S
authors.lastname: Heiba
authors.forename: Omash
authors.initials: O
authors.lastname: Uza
authors.forename: Suad
authors.initials: S
authors.lastname: Mahussein
authors.forename: Samira
authors.initials: S
authors.lastname: Al-Tailji
mesh_terms: D000328:Adult; D002983:Clinical Competence; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009683:Nuclear Medicine / Q000592:standards*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011877:Radionuclide Imaging / Q000592:standards; D012017:Referral and Consultation; D014692:Ventilation-Perfusion Ratio