Abstract Body (Do not enter title and authors here): Background: How the human body coordinates cerebral blood flow (CBF) and multi-organ inflammation during recovery of an acute myocardial infraction (AMI) is difficult to study and poorly understood. This is in part due to a lack of noninvasive measuring techniques for both blood flow (BF) and total-body (TB) inflammation per organ in treated survivors. Conventional PET imaging can either resolve organ-specific BF or tissue inflammation with a singular tracer injection but not both.
Hypothesis: We hypothesize that early kinetics and delayed static images from a single tracer injection for PET scans will simultaneously evaluate and connect, for the first time, CBF abnormalities and remote vascular (i.e. aorta) and/or solid organ inflammation at a singular time point.
Methods: Here, we expand our prior work on multiparametric TB-PET with high-temporal resolution dynamic imaging (1-2 s/frame for the first ~2 mins of scanning) for CBF modeling with a no-flow radiotracer (i.e. ¹⁸F-FDG) based on early vascular transit time (VTT) in the gray and white matter, brainstem, and cerebellum. The whole aorta, by target–to–blood pool ratio (TBR) at 40-60 min, and solid organs, by standardized uptake value (SUV) at 60-90 min, were evaluated for inflammation based on glucose uptake.
Result: Eleven revascularized survivors (~10 days post event) and 22 non-AMI subjects were studied. CBF was primarily reduced, when compared to controls, in subcortical gray matter (0.353 vs. 0.434 mL/min/cm³, p=0.0121) with a lesser reduction trend in cortical gray matter (0.414 vs. 0.449, p= 0.0677). This was accompanied by a gray matter subcortical increase in mean VTT (6 vs. 4.3 sec, p=0.0121) and to a lesser extend a cortical increase (5.5 vs. 4.5 sec, p=0.0253). The TBR and SUVs of extra-cardiac, non-cerebral organs were increased 1.9 vs. 1.23, p<0.0001 in the whole aorta, 2.9 vs. 2.2 p=0.0435 in the bone marrow and 3.1 vs. 2.1 p=0.0015 in the spleen respectively.
Conclusion: When simultaneously evaluating extra-cardiac organs in survivors, we found a widespread pattern of multi-organ inflammation and a restricted-to-regional hypoperfusion of subcortical > cortical gray matter using dynamic and static total-body ¹⁸F-FDG PET/CT imaging per organ, per patient and with a singular non-flow tracer injection. Hence, future longitudinal PET imaging on AMI survivors as shown offers a unique opportunity to unravel the complex process of recovery and the multiorgan contribution to resilience post MI.