Significant improvements and developments in fast scanning techniques for functional magnetic resonance (MR) imaging of the brain have occurred during the past year. We have been able to migrate all rapid imaging and spectroscopic imaging techniques to the 3 Tesla MR units. Improvements in signal to noise are observed with MR-based spin-tagging perfusion to detect cerebral blood flow, and clinical studies are being performed comparing the results of functional imaging studies at 1.5 Tesla and 3.0 Tesla. Evaluation of a newly developed proton spectroscopic imaging (MRSI) involves the acquisition of cerebral metabolites without suppression of the water signal. MRSI without water suppression revealed a low coefficient of variation of 5–13% for intrasubject and intersubject comparisons, which is an improvement over standard MRSI techniques that use water suppression. Improvements in this new non-water-suppressed MRSI technique will allow for the addition of a second echo that may be used to segment the signal originating from cerebral spinal fluid (versus intracellular water) and provide some information about the relaxation properties of the signals from cerebral metabolites.
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