Toward proton MR spectroscopic imaging of stimulated brain function

With the objective of complementing local cerebral metabolic studies of PET (positron emission tomography), and as a prelude to spectroscopic imaging, a localized proton spectroscopic study of the stimulated human auditory cortex was performed. Water suppressed localized spectroscopy (voxel size 3 cm*3 cm*3 cm enclosing the auditory cortex, T/sub e/=272 ms, T/sub r/=3 s) was performed on a 1.5-T MRI/MRS system, and spectra were acquired during stimulation with a 1 kHz tone presented at 2 Hz. Measurements were conducted for 30-40 min with a temporal resolution of 3.2 min (64 averages per time block). Results from six subjects show a lactate peak which increases during stimulation compared to baseline values. These results suggest an increase in anaerobic glycolysis during stimulation and provide valuable information that should complement glucose metabolism and blood flow studies of PET.<>