title: Quantitative assessment of myocardial perfusion abnormality on SPECT myocardial perfusion imaging is more reproducible than expert visual analysis.
abstract: BACKGROUND
  Current guidelines of Food and Drug Administration for the evaluation of SPECT myocardial perfusion imaging (MPI) in clinical trials recommend independent visual interpretation by multiple experts. Few studies have addressed whether quantitative SPECT MPI assessment would be more reproducible for this application.
  
  
  RESULTS
  We studied 31 patients (age 68 +/- 13, 25 male) with abnormal stress MPI who underwent repeat exercise (n = 11) or adenosine (n = 20) MPI within 9-22 months (mean 14.9 +/- 3.8 months) and had no interval revascularization or myocardial infarction and no change in symptoms, stress type, rest or stress ECG, or clinical response to stress on the second study. Visual interpretation per FDA Guidance used 17-segment, 5-point scoring by two independent expert readers with overread of discordance by a third expert, and percent myocardium abnormal was derived from normalized summed scores. The quantitative magnitude of perfusion abnormality was assessed by the total perfusion deficit (TPD), expressing stress, rest, and ischemic perfusion abnormality. High linear correlations were observed between visual and quantitative size of stress, rest, and ischemic defects (R = 0.94, 0.92, 0.84). Correlations of two tests were higher by quantitative than by visual methods for stress (R = 0.97 vs R = 0.91, P = 0.03) and rest defects (R = 0.94 vs R = 0.82, P = 0.03), respectively, and statistically similar for ischemic defects (R = 0.84 vs R = 0.70, P = ns).
  
  
  CONCLUSIONS
  In stable patients having serial SPECT MPI, quantification is more reproducible than visual for magnitude of perfusion abnormality, suggesting its superiority for use in randomized clinical trials and monitoring the effects of therapy in an individual patient.
authors.affiliation: Department of Imaging (Division of Nuclear Medicine), Cedars-Sinai Heart Institute, 8700 Beverly Boulevard, Room 1258, Los Angeles, CA 90048, USA. bermand@cshs.org
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Berman
authors.forename: Xingping
authors.initials: X
authors.lastname: Kang
authors.forename: Heidi
authors.initials: H
authors.lastname: Gransar
authors.forename: James
authors.initials: J
authors.lastname: Gerlach
authors.forename: John D
authors.initials: JD
authors.lastname: Friedman
authors.forename: Sean W
authors.initials: SW
authors.lastname: Hayes
authors.forename: Louise E J
authors.initials: LE
authors.lastname: Thomson
authors.forename: Rory
authors.initials: R
authors.lastname: Hachamovitch
authors.forename: Leslee J
authors.initials: LJ
authors.lastname: Shaw
authors.forename: Piotr J
authors.initials: PJ
authors.lastname: Slomka
authors.forename: Ling De
authors.initials: LD
authors.lastname: Yang
authors.forename: Guido
authors.initials: G
authors.lastname: Germano
mesh_terms: D000368:Aged; D000465:Algorithms; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D017202:Myocardial Ischemia / Q000150:complications / Q000000981:diagnostic imaging*; D015588:Observer Variation; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000000981:diagnostic imaging*