CHARACTERIZATION IN-VIVO OF MUSCLE-FIBER TYPES BY MAGNETIC-RESONANCE-IMAGING

Magnetic resonance imaging has been used to characterize muscle fiber types, Here, T-1 and T-2 values were determined in pure slow-twitch an d fast-twitch rabbit muscles and in rabbit muscles with mixed fiber ty pes, The muscles with high proportions of oxidative slow-twitch fibers had higher T-2 values than the others, Echo time, orientation of musc le fibers in B-0, and moving spins had no effect on relaxation paramet ers, The results are discussed in terms of slow myosin isoform content and oxidative metabolism. (C) 1998 Elsevier Science Inc.