EFFECT OF PROFOUND ISCHEMIA ON HUMAN MUSCLE - MRI, PHOSPHORUS MRS ANDNEAR-INFRARED STUDIES

A pressure cuff was applied to the legs of two human volunteers in ord er to stop any blood supply for a period of about 30 min, The affected muscle was monitored using proton magnetic resonance imaging (MRI), p hosphorus magnetic resonance spectroscopy (MRS) and near infrared (NIR ) spectroscopy before, during and after this procedure, The internal t emperature of the tissue was also measured, The phase of water protons in muscle showed changes that were not accounted for by the measured temperature, but which correlated with the large increase in deoxyhaem oglobin and deoxymyoglobin observed with NIR as well as the decrease i n PCr and increase in P-i observed with MRS, Little or no change was f ound in proton density or T-2. These results show that in vivo measur ements of temperature using the chemical shift method may be confounde d by changes in tissue oxygenation, They also show that T-2 is an ins ensitive measure of changes in tissue oxygenation. (C) 1997 by John Wi ley & Sons, Ltd.