Assessment of resting myocardial blood flow in regions of known transmural scar to confirm accuracy and precision of 3D cardiac positron emission tomography

Background Composite invasive and non-invasive data consistently demonstrate that resting myocardial blood flow (rMBF) in regions of known transmural myocardial scar (TMS) converge on a value of similar to 0.30 mL/min/g or lower. This value has been confirmed using the 3 most common myocardial perfusion agents (N-13, O-15-H2O and Rb-82) incorporating various kinetic models on older 2D positron emission tomography (PET) systems. Thus, rMBF in regions of TMS can serve as a reference truth to evaluate low-end accuracy of various PET systems and software packages (SWPs). Using 82Rb on a contemporary 3D-PET-CT system, we sought to determine whether currently available SWP can accurately and precisely measure rMBF in regions of known TMS. Results Median rMBF (in mL/min/g) and COV in regions of TMS were 0.71 [IQR 0.52-1.02] and 0.16 with 4DM; 0.41 [0.34-0.54] and 0.10 with 4DM-FVD; 0.66 [0.51-0.85] and 0.11 with Cedars; 0.51 [0.43-0.61] and 0.08 with EmoryVotaw; 0.37 [0.30-0.42], 0.07 with Emory-Ottawa, and 0.26 [0.23-0.32], COV 0.07 with HeartSee. Conclusions SWPs varied widely in low end accuracy based on measurement of rMBF in regions of known TMS. 3D PET using Rb-82 and HeartSee software accurately (0.26 mL/min/g, consistent with established values) and precisely (COV = 0.07) quantified rMBF in regions of TMS. The Emory-Ottawa software yielded the next-best accuracy (0.37 mL/ min/g), though rMBF was higher than established gold-standard values in similar to 5% of the resting scans. 4DM, 4DM-FDV, Cedars and Emory-Votaw SWP consistently resulted values higher than the established gold standard (0.71, 0.41, 0.66, 0.51 mL/min/g, respectively), with higher interscan variability (0.16, 0.11, 0.11, and 0.09, respectively).

Automated summary

There are variations in low-end accuracy when measuring myocardial blood flow using different software packages. 3D PET with Rb-82 and HeartSee software accurately and precisely measures myocardial blood flow, while other software packages show varying degrees of error and variability.