Comparison of treadmill exercise versus dipyridamole stress with myocardial perfusion imaging using rubidium-82 positron emission tomography.
OBJECTIVE
This study assessed the feasibility of treadmill exercise rubidium-82 ((82)Rb) positron emission tomography (PET) and compared image quality and diagnostic content with dipyridamole (82)Rb PET in patients referred for evaluation of coronary artery disease (CAD).


BACKGROUND
Dipyridamole stress (82)Rb PET myocardial perfusion imaging (MPI) is an accurate imaging modality used to diagnose CAD and determine prognosis. Although pharmacologic stress is used routinely, exercise treadmill stress may be an alternative and provide clinical information helpful to decision making, particularly for patients unwilling or unable to tolerate pharmacologic stress.


METHODS
Fifty patients (mean age, 60 +/- 10 years; 47 men) underwent treadmill exercise and dipyridamole (82)Rb PET. Images were assessed: 1) qualitatively using a 17-segment model and a semiquantitative visual score on a five-point scale and with calculation of summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS); and 2) quantitatively with a 70% threshold for abnormal perfusion and expressed as extent of abnormal perfusion (% left ventricular).


RESULTS
Treadmill exercise was preferred by 74% of patients (37 of 50, p < 0.001). The exercise and dipyridamole (82)Rb PET summed scores and quantitative extent of abnormal perfusion were very similar and highly correlated. Results of Bland-Altman analysis showed no significant bias. Image quality was superior with exercise stress with greater myocardial uptake and higher target to background ratios.


CONCLUSIONS
Treadmill exercise (82)Rb PET is feasible and provides imaging results of similar diagnostic content and superior image quality compared with dipyridamole stress. Treadmill exercise is a reasonable alternative to pharmacologic stress with (82)Rb PET MPI.
Chow
Benjamin J W
BJ
Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
Ananthasubramaniam
Karthikeyan
K
dekemp
Robert A
RA
Dalipaj
Mary M
MM
Beanlands
Rob S B
RS
Ruddy
Terrence D
TD
D003326:Coronary Circulation / Q000502:physiology*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D004176:Dipyridamole; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D011446:Prospective Studies; D012414:Rubidium Radioisotopes; D014665:Vasodilator Agents
D012414:Rubidium Radioisotopes; D014665:Vasodilator Agents; D004176:Dipyridamole