The effect of temperature on MR relaxation times and signal intensities for human tissues

T₁ andT₂ relaxation times were measured on human tissue samples of adipose tissue, muscle, bone marrow and osteolytic skeletal metastases at temperatures ranging from +37°C to –10°C. Relative signal intensities forT₁, proton density andT₂-weighted imaging sequences were also calculated.T₁ andT₂ of adipose tissue decreased almost linearly with decreasing temperature while for muscle, bone marrow and metastasesT₁ andT₂ decreased slightly to moderately, with temperature reduction to about –5 °C at which temperature a sudden marked decrease occurred. Calculated signal intensities showed a decrease in image contrast with temperature reduction and reversal of contrast between adipose tissue and the other tested tissues with all imaging sequences at temperatures around 0°C.