Electron paramagnetic resonance imaging of a model of a beating heart

This paper presents an apparatus that permits synchronization of the signal acquisition from a moving sample in electron spin resonance imaging experiments. The apparatus has been designed to observe a perfused beating heart and includes all the necessary apparatus to stimulate the heart and to synchronize the signal acquisition on this stimulus. The apparatus is completed by a low-frequency electron paramagnetic resonance bridge operated at 1.5 GHz, a re-entrant cavity for the sample and air coils to obtain the field gradients. Tests were carried out on a phantom consisting of a thin-walled silicon rubber tube of the approximate dimensions of a rat heart. The phantom movements are obtained by inflating and deflating the tube with a peristaltic pump that can be reversed by computer. The acquisitions are taken in synchronization with the pump positions. The hardware used to drive the pump and to synchronize the acquisitions is also described.