Cerebral blood volume is the blood volume in a given amount of brain tissue.[1]
The typical human adult's skull contains approximately 1500 grams of the brain (including gray matter and white matter), 100-130 milliliters of blood, and 75 milliliters of cerebrospinal fluid. About 15% of the blood volume is present in the arteries, 40% in the veins, and 45% in the nerve tissue and capillaries.[2]
There is a difference between the cerebral blood volume of gray and white matter. The cerebral blood volume value of gray matter is about 3.5 +/- 0.4 ml/100g, and the white matter is about 1.7 +/- 0.4 ml/100g. The gray matter is nearly twice that of white matter.[3] In both white and gray matter, cerebral blood volume decreases by about 0.50% per year with increasing age.[4] Intracranial hematoma and Intracerebral hemorrhage (ICH) will cause an increase in cerebral blood volume.[5] Ischemic stroke will cause a substantial reduction in cerebral blood volume.[6]
The cerebral blood volume maps can be calculated by dynamic magnetic resonance image set obtained by echo planar imaging after intravenous injection of thiol contrast agent.[7] Planar imaging techniques or single high-speed shots provide the necessary resolution for contrast agents to display rapid brain blood movements.[8] These magnetic resonance cerebral blood volume imaging methods can be applied to academic research of normal human brain activities and clinical studies of patients with brain tumors.[9][10]
In vivo studies using emission computed tomography gave coefficients of variation for regional cerebral blood volume and cross-sectional cerebral blood volume over 80 minutes.[11] A clear tomographic depiction of cerebral blood volume distribution in human subjects can achieve by using emission computed tomography, which provides real-time measurements of the cerebral hemodynamic parameters.[12] Carbon monoxide administered by a single inhalation is a reliable and accurate blood tracer for measuring cerebral blood volume with emission computed tomography.[13][14]
Synchrotron Radiation Computed Tomography uses a monochromatic and parallel X-ray beam to measure the value of cerebral blood volume. It allows the sample to be placed away from the detector, thereby avoiding scattering effects.[15] This technique measures absolute contrast concentration with relatively high precision and spatial resolution. Cerebral blood volume measurements are based on methods used in dynamic computed tomography. After a large dose of iodinated contrast agent was injected into the brain tissue, the temporal change in iodine concentration was compared to changes in cerebral arterial input. It is a new method for studying hemodynamic changes in brain pathophysiology, including clinical studies of cerebrovascular diseases or brain tumors.[16]
Cerebral blood volume is one of the parameters that is assessed with CT perfusion, often as part of Ischemic stroke evaluation.[17][18]
Cerebral blood volume has a close and positive correlation with cerebral blood flow. Both cerebral blood volume and cerebral blood flow depend on several important parameters, including cerebrovascular resistance, intracranial pressure, and mean arterial pressure.[1] The ratio between cerebral blood flow and cerebral blood volume can be an accurate predictor of decreased cerebral perfusion pressure, thereby predicting cerebral circulation.[19][20]