Ha. Smith et al., CORRELATION OF XENON-ENHANCED COMPUTED TOMOGRAPHY-DEFINED CEREBRAL BLOOD-FLOW REACTIVITY AND COLLATERAL FLOW PATTERNS, Stroke, 25(9), 1994, pp. 1784-1787
Background and Purpose A chronic compromise of cerebral hemodynamics h
as been shown to identify a group of patients at an increased risk for
stroke. Because a ''steal phenomenon'' induced by a vasodilatory chal
lenge has characterized the group at greatest risk, it was hypothesize
d that these individuals would also have a severe compromise of primar
y collaterals and an increased dependence on leptomeningeal collateral
s. Methods Twenty-three patients with symptomatic cerebrovascular dise
ase underwent angiography and xenon-enhanced computed tomographic cere
bral blood flow studies before and after 1 g IV acetazolamide within 6
months of each other. Cerebral blood flow vasoreactivity was classifi
ed by whether cerebral blood flow increased (>5%) or was unchanged (+/
-5%) (group 1) or fell by >5% (group 2) in any vascular territory. Ang
iographic collateralization was classified into four types: normal(typ
e 1), willisian (type 2), ophthalmic (type 3), and leptomeningeal (typ
e 4). Results Twenty percent (2/10) of group 1 patients and 69% (9/13)
of group 2 patients (P=.0009) had leptomeningeal collaterals. Conclus
ions A negative flow reactivity is significantly associated with a dep
endence on leptomeningeal collaterals and implies a state of maximal h
emodynamic compromise.