Cerebrovascular reactivity to acetazolamide in alert patients with cerebral infarction: usefulness of first-pass radionuclide angiography using Tc-99m-HMPAO in monitoring cerebral haemodynamics

Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were studied in 75 patients with cerebral infarction. All patients were alert with the symptoms of hemiparesis and/or aphasia, and were divided into two groups: 4 2 patients had occlusion or stenosis of >75% at the internal carotid artery or main trunk of middle cerebral artery; and 33 patients did not. Hemisphe ric mean CBF was measured by performing first-pass radionuclide angiography using Tc-99m-hexamethylpropylene amine oxime. CVR was measured as the perc entage change from the baseline mean CBF value after the administration of 500 mg acetazolamide. The CVR in both groups was significantly impaired (5. 2 +/- 6.3%, P < 0.001 and 7.7 +/- 6.1%, P<0.01, respectively) compared with normal controls (14.7+/-3.3%), although the mean CBF was not significantly reduced compared with age-matched controls. In the 12 patients with unilat eral carotid occlusion, five patients with good collateral flow via the ant erior communicating artery showed preserved CVR (11.0 +/- 7.8%),but those w ithout did not (1.6+/-7.0%). CVR is impaired in alert patients with cerebra l infarction, although the mean CBF is riot reduced, and good collateral fl ow via the anterior communicating artery in patients with carotid occlusion may be a sign of well-preserved haemodynamic status. ((C) 2001 Lippincott Williams & Wilkins).