title: Evaluating the Role of Routine Prone Acquisition on Visual Evaluation of SPECT Images.
abstract: Attenuation artifacts reduce our ability to evaluate perfusion of affected myocardial segments. The aim of this study was to evaluate the impact of routine prone-position image evaluation within a stepwise visual interpretation of myocardial perfusion studies.
  
  
  METHODS
  We have included 279 consecutive patients who were referred for evaluation of myocardial ischemia. All patients underwent routine electrocardiogram-gated supine SPECT imaging and non-electrocardiogram-gated prone-position SPECT imaging. Three nuclear medicine physicians interpreted the images in the following order: polar maps, supine images, raw images, motion-frozen gated images, and prone images, using a scale of 0-4. Segments with perfusion abnormalities were noted.
  
  
  RESULTS
  All physicians reported lower proportions of equivocal evaluations after evaluating prone images (18.3% vs. 4.7%, 19% vs. 11.1%, and 12.2% vs. 6.1%, P < 0.0001, P = 0.0077, and P = 0.0125, respectively). At the prone stage, normalcy rates were 89%, 87%, and 91%. Two physicians had significantly increased normalcy rates at the prone stage (72%-89%, P = 0.039, and 66%-87%, P = 0.006). At the prone stage, a decision reversal to normal or probably normal was observed in 40% (29/72), 33% (17/51), and 43% (21/48). In men, apical, mid, and basal inferior walls and in women apical and mid parts of anterior walls were more likely to be attributed to attenuation. The 2 steps that increased normalcy rates for interpreters were the review of raw images and of prone images.
  
  
  CONCLUSIONS
  Routine prone imaging increases interpretive certainty and interobserver agreement and changes the final evaluation in a substantial number of patients and significantly decreases the number of equivocal evaluations.
authors.affiliation: Department of Nuclear Medicine, Acibadem University, Istanbul, Turkey leventguner@yahoo.com.
authors.forename: Levent A
authors.initials: LA
authors.lastname: Guner
authors.affiliation: Department of Nuclear Medicine, Bolu Abant Izzet Baysal University, Bolu, Turkey.
authors.forename: Billur
authors.initials: B
authors.lastname: Caliskan
authors.affiliation: Department of Nuclear Medicine, Dumlupinar University, Kutahya, Turkey; and.
authors.forename: Ilknur
authors.initials: I
authors.lastname: Isik
authors.affiliation: Department of Nuclear Medicine, Acibadem University, Istanbul, Turkey.
authors.forename: Tamer
authors.initials: T
authors.lastname: Aksoy
authors.affiliation: Department of Nuclear Medicine, Acibadem University, Istanbul, Turkey.
authors.forename: Erkan
authors.initials: E
authors.lastname: Vardareli
authors.affiliation: Department of Cardiology, Dumlupinar University, Kutahya, Turkey.
authors.forename: Afsin
authors.initials: A
authors.lastname: Parspur
mesh_terms: D016477:Artifacts; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology; D055414:Myocardial Perfusion Imaging; D015588:Observer Variation; D016684:Prone Position; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D035501:Uncertainty
keywords: SPECT; myocardial perfusion; prone imaging