Fast (<5 minutes), Heart-Rate-Independent, Whole-Heart, Free-Breathing, Three-Dimensional Myocardial BOLD MRI at 3T and 13N-ammonia PET at Rest and Under Adenosine Stress in Canines with LAD Coronary Stenosis. Panel A shows representative basal, mid and apical short-axis T2 maps at rest and under stress, from a canine with LAD coronary stenosis. Panel D shows the corresponding quantitative myocardial blood flow (MBF) maps determined from 13N-ammonia PET. Note the close correspondence in the MBF distribution and T2 maps, particularly under adenosine stress. Specifically, the remote territories on PET images showed increased T2 values on T2 maps acquired under adenosine. Conversely, the affected territories on PET images (anterior wall corresponding to LAD territory; white arrows in zoomed-in images) showed markedly diminished increase in T2 (black arrows in zoomed-in images) compared to remote segments. Corresponding polar maps for BOLD and PET are shown in Panels B and E, respectively. Affected segments identified with change analysis from QPET are labeled with ‘+’ in the polar maps. Both BOLD Response and PET MPR showed significantly lower values in the affected territories compared to the remote segments (Panels C and F, respectively).