Abstract
The cerebral hemodynamics was studied in 5 patients with cerebral arteriovenous aneurysms using the nitrous oxide method and the dye-dilution method, and special reference was made to shunted blood flow. Cerebral blood flow measured by the nitrous oxide method tended to increase generally, while cerebral vascular resistance decreased. Dye-dilution curve from the internal jugular bulb following the injection into the carotid artery was characterized by the shortness of the appearance time and abnormal hump on the build-up slope. It was assumed that the first part of the curve represented shunted flow and the second wave normal cerebral blood flow. The proportion of dye passing through the shunt was obtained by the ratio of the area of shunt curve to the summed areas cf both curves on semilogarithmic paper. The shunt calculated from single dilution curve varied significantly according to experimental conditions of dye injection into the right or left carotid artery and dye recording from the right or left jugular bulb. The per cent values of the shunt in 4 cases estimated by averaging the right and left shunt ratios of the brain were 72, 53. 8, 33. 5 and 17. 6%. There existed a rough correlation between the shunt ratio of the brain and cerebral blood flow measured by the nitrous oxide method. In 2 cases, in which the tumors were surgically extirpated, pre-and postoperative studies were made.
