MR microscopy on rats in vivo at 4.7 T using surface coils

MR microscopy on intact rats using a single surface coil is reported. The use of the same coil for excitation and detection is experimentally very simple and results in a smaller field-of-view than the conventional setup using homogeneous excitation (whole-body coil or a large surface coil) and a small receiver surface coil. Images at 4.7 T with 60 X 60-microns pixels and an 800-microns slice thickness have been obtained from the eye and ankle joint of a living rat with good anatomical definition. This corresponds to a four- to eightfold reduction in voxel size as compared to high-resolution images obtained with a 30-mm resonator probe. Many of the basic MRI experiments (spin-echo, FLASH, chemical-shift selective MRI) may be carried out in a straightforward way with this one-coil setup. Sequences relying on a homogeneous flip angle distribution require a whole-body excitation coil.