Streamlined quantification of absolute MBF at rest and stress with flurpiridaz F-18 injection PET in normal subjects and patients with coronary artery disease (CAD)

Objectives Flurpiridaz F-18 is a new PET myocardial perfusion tracer that is currently undergoing clinical evaluation. We investigated the feasibility of streamlined quantification of rest (R) and stress (S) myocardial blood flows (MBFs) and coronary flow reserve (CFR) with this tracer for clinical use in normal subjects (NS) and CAD patients (Pts).

Methods Ten Pts [6 NS; 4 with CAD (>50% stenosis) and reversible defects] received flurpiridaz F-18 injection at R and at peak adenosine S followed by 10-min dynamic scan. The R-S imaging was same-day in 5 Pts and separate-day in 5 Pts. R and S polar maps (PM) were generated from summed image ( 0.5-2 min) and the 3 coronary territories (LAD, RCA, LCX) and the left ventricular blood pool (LV) were defined. Reversible defects were manually assigned on PM, from which time activity curves (TACs) were generated. A compartment model that included an irreversible uptake constant (K) and a spillover from blood pool was used to fit the tissue TACs (0-2 min). LV TAC was the input function. Partial volume effect of tissue was estimated as (1-spf), with spf denoting the blood spillover fraction obtained from fitting. The first-pass extraction fraction for flurpiridaz F-18 was assumed to be 0.94 based on pre-clinical studies. CFR was calculated as S/R MBF.

Results MBF and CFR were compared between 18 normal territories ( in 6 NS) and 5 reversible defect regions (Table, * indicates p<0.05). The results agree with the published results using N-13 ammonia PET.

Conclusions Quantification of MBF using flurpiridaz F-18 injection cardiac PET can be streamlined in clinical settings to give robust MBF results

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