LOCALIZED PROTON MR SPECTROSCOPY OF THE HUMAN KIDNEY IN-VIVO BY MEANSOF SHORT ECHO TIME STEAM SEQUENCES

In order to obtain proton magnetic resonance spectra from the normal h uman kidney in vivo, we employed a STEAM sequence with delay times TE = 10 ms and TM = 30 ms. Signals are attenuated during STEAM sequences by J-coupling effects and by macroscopic movement of the sample. The c ombination of short echo times and respiratory triggering ensured that the kidney was stationary during the pulse sequence, and allowed us t o detect strongly coupled resonances between 3 and 4.2 ppm. Analysis o f spectra of extracts of bovine kidneys suggested that the renal MR-vi sible metabolites could include the osmolytes betaine, myo-inositol, a nd glycerophosphocholine. Four volunteers were subjected to overnight dehydration followed by rehydration, and we found that these signals i ncreased significantly after dehydration, and decreased significantly 4 h after rehydration, thus supporting the assignment of the resonance s as osmotically active metabolites.