FUNCTIONAL MR OF BRAIN ACTIVITY AND PERFUSION IN PATIENTS WITH CHRONIC CORTICAL STROKE

PURPOSE: (1) To determine whether functional MR can reliably map funct ional deficits in patients with stroke in the primary visual cortex; ( 2) to determine whether functional MR can reliably map perfusion defic its; and (3) to determine whether functional MR can give any additiona l diagnostic information beyond conventional MR. METHODS: Seven patien ts who had had a stroke in their primary visual system were examined u sing two functional MR techniques: (1) dynamic susceptibility contrast imaging, and (2) cortical activation mapping during full-field visual stimulation. Maps of relative cerebral blood volume and activation we re created and compared with visual field examinations and conventiona l T2-weighted images on a quadrant-by-quadrant basis in five of these patients. RESULTS: Visual field mapping matched with both T2-weighted conventional images and activation mapping of 16 of 18 quadrants. In t wo quadrants, the activation maps detected abnormalities that were pre sent on the visual field examination but not present on the T2-weighte d images nor on the relative cerebral blood volume maps, which may ind icate abnormal function without frank infarction. In addition, the act ivation maps demonstrated decreased activation in extrastriate cortex and had normal T2 signal and relative cerebral blood volume but was ad jacent to infarcted primary cortex, mapping in vivo how stroke in one location can affect the function of distant tissue. CONCLUSION: Functi onal MR techniques can accurately map functional and perfusion deficit s and thereby provide additional clinically useful information. Additi onal studies will be needed to determine the prognostic utility of fun ctional MR in stroke patients.