HETEROGENEITY OF CEREBRAL HEMODYNAMICS AND METABOLISM IN CAROTID-ARTERY DISEASE

Methods: Eight patients with severe unilateral carotid stenosis (>70%) were evaluated using PET to assess parametric changes in cerebral blo od flow, blood volume, metabolic rate for oxygen, metabolic rate for g lucose, oxygen extraction fraction and glucose extraction fraction, We performed these examinations because clinical history and physical ex am results suggested possible cerebral vascular disease, Four patients were neurologically asymptomatic with other signs of peripheral vascu lar disease (e,g,, episodic vertigo, TIA and claudication), All patien ts had normal neurologic examinations and normal CT or MRI studies, PE T images were analyzed by two methods, First, regions of interest were used for the entire hemisphere, vascular territories and borderzones, Regions ipsilateral to the carotid stenosis were compared to respecti ve regions in the contralateral hemisphere using Student's t-test, Sec ond, visual inspection of each image was performed, Results: Statistic al analysis demonstrated no significant differences between hemodynami c and metabolic parameters for regions ipsilateral to the carotid sten osis and contralateral homotopic reference regions. Upon visual examin ation, however, all patients had focal changes in either cerebral bloo d flow, blood volume, glucose extraction fraction and/or oxygen extrac tion fraction. Conclusion: Visual inspection is important in the evalu ation of pathophysiological changes caused by unilateral carotid steno sis, Clinical decisions in patients with carotid artery disease should be based on careful visual examinations and statistical analyses of a ppropriately selected regions.