A ccurate anatomical localization, highly desirable in neuroanatomic imaging, is critical in surgical applications. We recently showed that spin echo sequences tend to indicate activation in gray matter because of a presumed sensitivity to capillary changes, whereas the more conventional gradient echo sequences tend to indicate activation in the cerebral spinal fluid spaces, probably because they are more sensitive to changes occurring in the draining veins. The sensitivity of spin echo sequences to gray matter activation make them a more natural vehicle for functional magnetic resonance imaging (fMRI). We evaluate the use of mixed spin echo-gradient echo sequences for this purpose, which should have a more general applicability at the 3-Tesla field strengths that will shortly become available at NYU School of Medicine.

Using positron emission tomography (PET) in collaboration with North Shore University Hospital, we propose to investigate the neuroanatomical circuitry of movement disorders. We use a novel approach in which a glucose metabolism brain scan is performed in the waking state and compared with a metabolic scan in the sleeping state, making it possible for the first time to define particular neuronal circuits involved in a syndrome of cranial dystonia. We apply this technique to study the various fragments of movement disorder found at different times in a patient with Parkinson disease, including hyperkinesia, akinesia, and tremor. We will compare scans of these states to a sleep study as a reference state, using principal component analysis. In addition to exploring the physiology of the movements, we expect to reveal possible sites for ablative surgical treatments of these disorders.