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Cerebral perfusion reserve indexes determined by fluoromethane positron emission scanning

Journal Article · · Stroke; (United States)

An index of cerebral perfusion reserve (RES%), defined as the percent change of regional cerebral blood flow over baseline per mm Hg of end-tidal CO/sub 2/ tension, was determined for each middle cerebral artery (MCA) territory in patients with unilateral carotid distribution transient ischemic attacks or minor cerebrovascular accidents and was compared with that of age-matched, neurologically normal volunteers. Vasodilator responses to induced hypercapnia were tested during inhalation of 5% CO/sub 2/ in 95% O/sub 2/ while regional cerebral blood flow was measured by fluoromethane inhalation positron emission tomography. Mean RES% for 24 normal MCA territories was 5.2 +/- 0.8%. Mean RES% for 15 patient nonischemic MCA territories was 3.8 +/- 1.3% and for 15 ischemic MCA territories was 2.8 +/- 1.9% (both p less than 0.001). Individual RES% values and symmetry ratios between ischemic and nonischemic regions were also determined and compared with angiographic data. Areas of diminished, asymmetric, or paradoxical (two patients) CO/sub 2/ reactivity appear to correspond to areas of compensatory vasodilation. We found this technique to be a safe and reproducible method for defining and recording localized areas of cerebral tissue at apparent risk for hemodynamically related damage.

Research Organization:
William S. Middleton Memorial Veterans' Hospital, Madison, WI
OSTI ID:
5470930
Journal Information:
Stroke; (United States), Journal Name: Stroke; (United States) Vol. 19:1; ISSN SJCCA
Country of Publication:
United States
Language:
English