MODELING AND OBSERVATION OF TEMPERATURE-CHANGES IN-VIVO USING MRI

Models have been developed for the signal changes occurring in human p eripheral muscle after thermal stress for some methods of measuring te mperature in vivo. These include the dependency of T-1 on temperature, observed by both direct, and magnetization transfer, experiments, and the temperature sensitivity of the diffusion coefficient and the chem ical shift of the water proton line. Results show the relative complex ity of the T-1-dependent models when there are significant variations in, possibly amongst other things, tissue perfusion, and how the predi ctions made using them match the behavior of the practical values quit e well. Using changes in the diffusion coefficient appears less proble matic, although there can still be significant errors in temperature c alibrations. The problems with this approach are likely to be due to t he consequences of anisotropy in tissue.