Journal of Nuclear Cardiology

, Volume 20, Issue 1, pp 64–75

Validation of an axially distributed model for quantification of myocardial blood flow using 13N-ammonia PET


    • Department of RadiologyUniversity of Washington
  • James B. Bassingthwaighte
    • Department of RadiologyUniversity of Washington
    • Department of BioengineeringUniversity of Washington
  • Robb Glenny
    • Department of MedicineUniversity of Washington
    • Departments of Physiology and BiophysicsUniversity of Washington
  • James H. Caldwell
    • Department of RadiologyUniversity of Washington
    • Department of BioengineeringUniversity of Washington
    • Department of MedicineUniversity of Washington
Original Article

DOI: 10.1007/s12350-012-9632-8

Cite this article as:
Alessio, A.M., Bassingthwaighte, J.B., Glenny, R. et al. J. Nucl. Cardiol. (2013) 20: 64. doi:10.1007/s12350-012-9632-8



Estimation of myocardial blood flow (MBF) with cardiac PET is often performed with conventional compartmental models. In this study, we developed and evaluated a physiologically and anatomically realistic axially distributed model. Unlike compartmental models, this axially distributed approach models both the temporal and the spatial gradients in uptake and retention along the capillary.


We validated PET-derived flow estimates with microsphere studies in 19 (9 rest, 10 stress) studies in five dogs. The radiotracer, 13N-ammonia, was injected intravenously while microspheres were administered into the left atrium. A regional reduction in hyperemic flow was forced by an external occluder in five of the stress studies. The flow estimates from the axially distributed model were compared with estimates from conventional compartmental models.


The mean difference between microspheres and the axially distributed blood flow estimates in each of the 17 segments was 0.03 mL/g/minute (95% CI [−0.05, 0.11]). The blood flow estimates were highly correlated with each regional microsphere value for the axially distributed model (y = 0.98x + 0.06 mL/g/minute; r = 0.74; P < .001), for the two-compartment (y = 0.64x + 0.34; r = 0.74; P < .001), and for three-compartment model (y = 0.69x + 0.54; r = 0.74; P < .001). The variance of the error of the estimates is higher with the axially distributed model than the compartmental models (1.7 [1.3, 2.1] times higher).


The proposed axially distributed model provided accurate regional estimates of MBF. The axially distributed model estimated blood flow with more accuracy, but less precision, than the evaluated compartmental models.


Myocardial blood flowcardiac PETquantitative PETdynamic imagingNH3

Copyright information

© American Society of Nuclear Cardiology 2012