Noninvasive monitoring of human brain temperature using ¹H magnetic resonance spectroscopy

Abstract

The accurate measurements of human brain temperatures at physiological conditions have not yet been easy. We tried to measure the human brain temperature change in normal adult volunteers during drinking of cold/warm water and exercises. Noninvasive temperature measurements were done using ¹H magnetic resonance spectroscopy (¹H-MRS) at 3.0T. We could detect a transient temperature fall of about 0.5°C with drinking of cold water (500mL/0°C). After drinking, the brain temperature rose gradually. The brain temperature rose about 0.4°C with drinking of warm water (500mL/53°C). These temperature changes were transient and larger than that by heat loss and gain of cold and warm waters. Therefore, these results show that the human brain temperature is affected by the pharyngeal and esophagus temperatures. The brain temperature change was also detected during light exercise such as knee flexion of 1Hz. The brain temperature rose monotonously about 0.5°C with 30min exercise and fell gradually after the end of exercise. This brain temperature change was larger than that of esophagus. These results indicate that the heat balance in the brain changes during exercise. We could measure the human brain temperature changes at physiological conditions using ¹H-MRS. [J Physiol Sci. 2007;57 Suppl:S180]