In vivo characterization of rodent cyclic myocardial perfusion variation at rest and during adenosine-induced stress using cine-ASL cardiovascular magnetic resonance

Abstract

Background: Assessment of cyclic myocardial blood flow (MBF) variations can be an interesting addition to the characterization of microvascular function and its alterations. To date, totally non-invasive in vivo methods with this capability are still lacking. As an original technique, a cine arterial spin labeling (ASL) cardiovascular magnetic resonance approach is demonstrated to be able to produce dynamic MBF maps across the cardiac cycle in rats. Method. High-resolution MBF maps in left ventricular myocardium were computed from steady-state perfusion-dependent gradient-echo cine images produced by the cine-ASL sequence. Cyclic changes of MBF over the entire cardiac cycle in seven normal rats were analyzed quantitatively every 6ms at rest and during adenosine-induced stress. Results: The study showed a significant MBF increase from end-systole (ES) to end-diastole (ED) in both physiological states. Mean MBF over the cardiac cycle within the group was 5.5 ± 0.6 mL g -1 min-1 at rest (MBFMin = 4.7 ± 0.8 at ES and MBFMax = 6.5 ± 0.6 mL g-1 min-1 at ED, P = 0.0007). Mean MBF during adenosine-induced stress was 12.8 ± 0.7mL g-1 min-1 (MBFMin = 11.7±1.0 at ES and MBFMax = 14.2 ± 0.7 mL g-1 min-1 at ED, P = 0.0007). MBF percentage relative variations were significantly different with 27.2 ± 9.3% at rest and 17.8 ± 7.1% during adenosine stress (P = 0.014). The dynamic analysis also showed a time shift of peak MBF within the cardiac cycle during stress. Conclusion: The cyclic change of myocardial perfusion was examined by mapping MBF with a steady-pulsed ASL approach. Dynamic MBF maps were obtained with high spatial and temporal resolution (6ms) demonstrating the feasibility of non-invasively mapping cyclic myocardial perfusion variation at rest and during adenosine stress. In a pathological context, detailed assessment of coronary responses to infused vasodilators may give valuable complementary information on microvascular functional defects in disease models. © 2014 Troalen et al.; licensee BioMed Central Ltd.