OPTIMIZING CONVENTIONAL CARDIAC MRI IN THE RABBIT AT 0.3-T

The aim of this study was to define the most efficient way of performi ng cardiac MRI for anatomic information in small experimental animals, using a vertical magnetic field with a strength of 0.3 T (FONAR beta- 3000M). This information may be used to improve cardiac MRI in infants and small children, since the size of a rabbit is considered comparab le to that of a neonate. Experimental axial cardiac MRI studies were p erformed in a rabbit under general anesthesia in order to study the ef fects on image quality of changing various imaging parameters. These a re ECG-gating, number of excitations (averages), number of warp levels , echo time (TE) and repetition time (TR). The effects of changing the size of the field of view (FOV), the slice thickness and the phase-en coding direction were also studied. We found that ECG-gating was cruci al and that three excitations, TE 16 ms, and 257 vertical phase-encodi ng warp levels were adequate. Five-millimeter slice thickness and FOV 20 cm were preferred.