Background: Stress only SPECT myocardial perfusion imaging (MPI) is a validated strategy to streamline cardiac diagnostic imaging. The potential use of Rb82 PET stress only MPI has not been investigated.
Methods and results: Stress images from 200 Rb82 PET-MPI were reviewed by two blinded readers and categorized as not requiring additional rest images (normal) or requiring additional images (abnormal or equivocal). No additional images were deemed necessary for 95 (48%) and 99 (50%) by the two blinded readers. The stress only interpretation was compared to the previous read of the complete rest-stress study. The rate of detecting a normal result with stress only reading was 76%-79% with a negative predictive value of 94%-95%. Clinical predictors of a normal stress only PET-MPI included lower age, the absence of CAD, and female gender, but not body mass index. Blinded reads of 50 additional consecutive PET-MPI from patients with selected clinical predictors (age <65 years, no known CAD) were then performed. Of these, 40 (80%) were normal by previous rest-stress reading, and 34 (68%) were categorized as not requiring additional images after stress only reading. PET stress only imaging would have resulted in a mean reduction of radiation exposure of 2.4 mSv per study according to a published radiation estimate.
Conclusion: Stress only Rb82 PET-MPI is a feasible strategy to reduce resource utilization and radiation exposure associated with MPI. This strategy would be most applicable to patients with a lower pretest likelihood.