Simultaneous quantification of myocardial perfusion, oxidative metabolism, cardiac efficiency and pump function at rest and during supine bicycle exercise using 1-11C-acetate PET - a pilot study

P>Background: PET using 1-11C-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. Methods: 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. Results: MBF increased from 0 center dot 71 +/- 0 center dot 17 to 2 center dot 48 +/- 0 center dot 25 ml min-1 per ml, LV-k(mono) from 0 center dot 050 +/- 0 center dot 005 to 0 center dot 146 +/- 0 center dot 021 min-1, RV-k(mono) from 0 center dot 023 + 0 center dot 006 to 0 center dot 087 + 0 center dot 014 min-1, RPP from 4 center dot 7 +/- 0 center dot 8 to 13 center dot 2 +/- 1 center dot 4 mmHg x min-1 x 103 and Cardiac Output from 5 center dot 2 +/- 1 center dot 1 to 12 center dot 3 +/- 1 center dot 2 l min -1 (all P < 0 center dot 001). Cardiac efficiency was unchanged (P = 0 center dot 99). Lung uptake decreased from 1 center dot 1 +/- 0 center dot 2 to 0 center dot 6 +/- 0 center dot 1 ml g-1 (P < 0 center dot 001). Discussion: 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.