Simultaneous quantification of myocardial perfusion, oxidative metabolism, cardiac efficiency and pump function at...

PET using 1-(11)C-acetate (ACE-PET) applied at rest is used for measuring absolute myocardial blood flow (MBF) and oxidative metabolic rate (k(mono)). We evaluated the feasibility of quantitative ACE-PET during exercise.

Five endurance athletes underwent dynamic PET scanning at rest and during supine bicycle stress. Exercise was maintained at a workload of 120 Watt for 17 min. The rate-pressure product (RPP) was recorded repeatedly. MBF, k(mono) in left (LV) and right (RV) ventricular wall, cardiac output (CO), cardiac efficiency and a lung uptake value reflecting left heart diastolic pressures were calculated from the PET data using previously validated models.

MBF increased from 0.71 +/- 0.17 to 2.48 +/- 0.25 ml min(-1) per ml, LV-k(mono) from 0.050 +/- 0.005 to 0.146 +/- 0.021 min(-1), RV-k(mono) from 0.023 + 0.006 to 0.087 + 0.014 min(-1), RPP from 4.7 +/- 0.8 to 13.2 +/- 1.4 mmHg x min(-1) x 10(3) and Cardiac Output from 5.2 +/- 1.1 to 12.3 +/- 1.2 l min (-1) (all P < 0.001). Cardiac efficiency was unchanged (P = 0.99). Lung uptake decreased from 1.1 +/- 0.2 to 0.6 +/- 0.1 ml g(-1) (P < 0.001).

A number of important parameters related to cardiac function can be quantified non-invasively and simultaneously with a short scanning protocol during steady state supine bicycling. This might open up new opportunities for studies of the integrated cardiac physiology in health and early asymptomatic disease.