Tissue temperature monitoring using magnetic resonance imaging

It is known that the longitudinal-relaxation time, T₁, 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°C-50°C to determine the optimal temperature sensitivity and resolution by testing various T₁ weighted MRI protocols. The three best MRI protocols were also tested within the temperature range of 30°C-40°C on in vitro tissues. In the phantom study, Turbo Spin Echo (TSE) sequence with a T_R of 425 msec obtained best results with 0.72°C temperature resolution and 12.7/°C temperature sensitivity. In tissue studies, TSE sequence obtained 4.41°C, 7.60°C, 4.81°C temperature resolutions and 5.90/°C, 5.20/°C, 6.73/°C temperature sensitivities for liver, spleen and kidney respectively. Moreover, it was shown that temperature dependence of tissues can be used in tissue discrimination