title: In vivo measurement of regional cerebral haematocrit using positron emission tomography.
abstract: A method is described for measuring the regional cerebral-to-large vessel haematocrit ratio using inhalation of carbon-11-labelled carbon monoxide and the intravenous injection of carbon-11-labelled methyl-albumin in combination with positron emission tomography. The mean value in a series of nine subjects was 0.69. This is approximately 20% lower than the value of 0.85 previously reported. It is concluded that previous measurements of regional cerebral blood volume using a haematocrit ratio of 0.85 will have underestimated the value of regional cerebral blood volume by 20%.
mesh_terms: D000418:Albumins; D002248:Carbon Monoxide; D002250:Carbon Radioisotopes; D002560:Cerebrovascular Circulation; D006400:Hematocrit; D006801:Humans; D008433:Mathematics; D008722:Methods; D014055:Tomography, Emission-Computed
chemical_list: D000418:Albumins; D002250:Carbon Radioisotopes; D002248:Carbon Monoxide