title: Assessment of transient ischemic dilation (TID) ratio in gated SPECT myocardial perfusion imaging (MPI) using regadenoson, a new agent for pharmacologic stress testing.
abstract: BACKGROUND
  Abnormal values of the transient ischemic dilation (TID) ratio are associated with severe and extensive coronary artery disease (CAD). The objective of this study was to determine the relationship between TID, determined from stress and rest ventricular volumes during regadenoson gated single-photon emission computed tomography myocardial perfusion imaging (MPI) dual isotope studies, and the extent of CAD found during coronary angiography.
  
  
  METHODS
  195 patients who underwent dual isotope MPI with regadenoson and cardiac angiography between March 2009 and February 2010 were analyzed. TID was calculated using commercially available software, Emory Cardiac Toolbox. Mean TID values were compared across disease types. A threshold for abnormal TID was determined by adding two standard deviations (SDs) to the mean TID of the "non-obstructive CAD" subgroup.
  
  
  RESULTS
  In the 195-patient group analyzed, the mean TID ratio for non-obstructive CAD (n = 104) was found to be 1.09 with a SD of 0.15. In a subgroup of patients whose angiogram was within 3 months of MPI (n = 155), the mean TIDs for non-obstructive disease (n = 81), single-vessel disease (n = 35), and multi-vessel disease (n = 39) were 1.09, 1.15, and 1.19 with SDs of 0.16, 0.19, and 0.26, respectively. Those with an abnormal TID had a crude and adjusted odds ratio of 3.4 for multi-vessel disease which was statistically significant. History of diabetes was not found to be a significant confounder, effect modifier, or mediator of the relationship between the TID and the vessel disease.
  
  
  CONCLUSIONS
  The mean TID ratio in patients with multi-vessel disease was 1.19. The threshold for an abnormal TID was 1.39 with specificity of 95% and sensitivity of 15% for determining multi-vessel CAD status. We conclude that the level of TID in gated SPECT MPI using regadenoson is associated with the degree of CAD on angiography.
authors.affiliation: Department of Medicine, Beth Israel Medical Center, Manhattan Campus of the Albert Einstein College of Medicine, New York, NY, USA. jkatz@chpnet.org
authors.forename: J S
authors.initials: JS
authors.lastname: Katz
authors.forename: M
authors.initials: M
authors.lastname: Ruisi
authors.forename: K N
authors.initials: KN
authors.lastname: Giedd
authors.forename: M
authors.initials: M
authors.lastname: Rachko
mesh_terms: D058908:Adenosine A2 Receptor Agonists / Q000494:pharmacology*; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000473:pathology*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D016017:Odds Ratio; D011687:Purines / Q000494:pharmacology*; D011720:Pyrazoles / Q000494:pharmacology*; D019275:Radiopharmaceuticals / Q000494:pharmacology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D058908:Adenosine A2 Receptor Agonists; D011687:Purines; D011720:Pyrazoles; D019275:Radiopharmaceuticals; C430916:regadenoson