1984 Volume 24 Issue 12 Pages 915-921
Local cortical blood flow (LCBF) was measured during extracranial-intracranial (EC-IC) bypass surgery in 14 hemispheres of 12 patients with moyamoya disease, 8 hemispheres of 8 patients with occlusion or stenosis of the internal carotid or middle cerebral artery, and 2 hemispheres of 2 patients with an unruptured internal carotid aneurysm. Measurement of LCBF was performed with the clearance method of hydrogen gas generated by electrolysis (H2-method) and the heat clearance method (heat-method), using the plate type probe in both methods.
LCBF measured by the H2-method was distinctly lower in all the patients with occlusive lesions before the EC-IC bypass, than in one patient without occlusive lesions. LCBF after bypass was increased in the territory of the recipient artery of all the patients with occlusive lesions, including moyamoya disease, except for one patient with stenosis of the middle cerebral artery. LCBF was not always increased after bypass in the area apart from the recipient artery, or the area on the opposite side of the Sylvian fissure of the patients with moyamoya disease. The LCBF measured by the heatmethod was hardly decreased by the clamping of the recipient artery in the part near the recipient artery before the bypass. The LCBF measured by the heat-method was promptly decreased by the clamping of the donor artery and increased by the release of the clamp after bypass. According to this evidence, the patency of the anastomosis and the surface area fed by the donor artery were confirmed after bypass. CO2 reactivity was studied by the heat-method in patients with moyamoya disease. In many of them, LCBF was not increased during hypercapnia but was decreased during hypocapnia. In the patients with unruptured internal carotid aneurysm, the heat-method was useful for determining the influence of clamping of the internal carotid artery on the LCBF before permanent ligation of the internal carotid artery.
The H2-method is quantitative but interrupted, whereas the heat-method is continuous qualitative. It is quite possible that simultaneous LCBF measurements by both methods during bypass surgery are useful not only for the study of the cerebral hemodynamics but also for the monitoring system during operation.
