Is ultra-short ECG gated acquisition of C-11 acetate PET reliable for simultaneous MBF, oxidative metabolism and myocardial function assessment?

Objectives C-11 acetate PET has a potential to evaluate three essential myocardial parameters, flow, metabolism and function in single acquisition. Dynamic-gated-dynamic sequential acquisition protocol was performed to evaluate this potential.

Methods Six patients (age 85-40, 3males and 3 females) with acute myocardial infarction (within one month after onset) were studied. Under fasting condition, C-11 acetate PET images were acquired using 3 min dynamic - 4min ECG gated - 12 min dynamic acquisition protocol following 700MBq of C-11 acetate intravenous injection. Then, oral glucose loading with additional intracutaneous insulin administration was performed. Injected dose of insulin was determined using blood sugar level measured just before insulin administration. About 1 hour after glucose loading, 180 MBq of FDG was injected. After 50 min waiting period, 10min ECG gated acquisition were performed. Gated images of 4min Acetate PET and 10min FDG PET imaging were analyzed with automated gated SPECT analysis program (pFAST2), then calculated left ventricular ejection fractions (EF) were compared. Using first 3 minute and last 12 min data of acetate PET, parametric images of absolute myocardial blood flow and washout rate of acetate were also created using previously reported methods.

Results EF measured with EGG gated C-11 acetate PET and FDG PET were 39.8±8.4 % and 42.8±9.1 % respectively. Those measurement ware significantly correlated (p=0.013), and no significant difference was found between two measurement although EF measured with FDG tends to show larger value. R-square of these two measurement was 0.816.

Conclusions C-11 acetate has a potential to measure absolute flow, metabolism and function in one single acquisition protocol even with very short duration of ECG gated acquisition