[Measurement of cerebral blood volume by reflections spectrophotometry: methodological improvement and quantitative...

The authors described methodological improvement and quantitative evaluation in measurement of cerebral blood volume (CBV) by reflectance spectrophotometry. The measurement of blood volume by this method has not been applied to the brain tissue because of the methodological difficulties. In order to obtain the accurate CBV values with this method, it is necessary to keep the proper contact between the sensor for the measurement and the brain tissue to be measured. For this purpose we developed a balance arm. A sensor for CBV measurement was fixed with the one side of the arm and a weight was installed to the other side. The pressure of the sensor to the brain can be adjusted by moving the weight, and the sensor was placed on the brain tissue with the proper pressure. Moreover, the sensor was attached with an acryl-made cap to make the pressure adjustment easier by enlarging the contact surface and to enable to observe the vasculature on the surface of the brain. With this improved method the reasonable changes of CBV could be obtained when the CO2 gas was inhalated and cerebral ischemia was produced in cats. The possibility of the quantitative evaluation was investigated using the homogenized brain tissue of cats. After the elimination of the blood from the brain by the perfusion with the saline, the brain was removed and homogenized. Then, the definite volume of blood, of which hemoglobin volume was already known, was added and measured by this method.(ABSTRACT TRUNCATED AT 250 WORDS)