Measurement of Brain Tissue Density Using Pycnometry
A novel method to measure specific gravity (SG) of tissues, pycnometry (PYC), is described. This method utilizes a 2 ml glass pycnometer filled with distilled H2O to determine the displacement volume of a tissue sample and an equation to compute SG from the sample’s weight and the pycnometer’s weight before and after adding the sample. The PYC method was validated using glass SG standards over the range 1.02–1.26, and against the column density gradient (DG) method using brain tissue from 250–300 g male rats. Factors which affect PYC accuracy, i.e. sample size, were also evaluated. Our results indicate that PYC SG values are highly correlated with the glass SG standards (slope = 1.0107, r = 0.9955, p < 0.001), and highly correlated with DG when ~0.120 ml tissue samples are used in the pycnometer. The DG method was preferable to the PYC method, however, when small tissue samples, i.e. 0.60 ml or less, were used.
KeywordsSpecific Gravity Specific Gravity Local Cerebral Blood Flow Small Tissue Sample Vasogenic Brain Oedema
Unable to display preview. Download preview PDF.
- 1.Klatzo I, Chui E, Fujiwara K (1980) Resolution of vasogenic brain oedema. In: Cervos-Navaro J, Ferszt R (eds) Advances in neurology, Vol 28. Raven Press, New YorkGoogle Scholar
- 3.Marmarou A et al (1980) Biomechanics of brain oedema and effects on local cerebral blood flow. In: Cervos-Navarro J, Ferszt R (eds) Advances in neurology, Vol 28. Raven Press, New YorkGoogle Scholar