Tissue temperature monitoring using magnetic resonance imaging

It is known that the longitudinal-relaxation time, T/sub 1/, is tissue specific and dependent on temperature. Hence, tissue characteristics under thermally changing conditions were investigated by using Magnetic Resonance Imaging and a new method for discriminating tissues was proposed. Phantom studies were performed within the temperature range of 30/spl deg/C-50/spl deg/C to determine the optimal temperature sensitivity and resolution by testing various T/sub 1/ weighted MRI protocols. The three best MRI protocols were also tested within the temperature range of 30/spl deg/C-40/spl deg/C on in vitro tissues. In the phantom study, Turbo Spin Echo (TSE) sequence with a T/sub R/ of 425 msec obtained best results with 0.72/spl deg/C temperature resolution and 12.7//spl deg/C temperature sensitivity. In tissue studies, TSE sequence obtained 4.41/spl deg/C, 7.60/spl deg/C, 4.81/spl deg/C temperature resolutions and 5.90//spl deg/C, 5.20//spl deg/C, 6.73//spl deg/C temperature sensitivities for liver, spleen and kidney respectively. Moreover, it was shown that temperature dependence of tissues can be used in tissue discrimination.