Comparative Reassessment of the Gravimetric and the Drying-Weighing Methods

Effective research in brain edema requires a reliable method for the determination of brain water content. The gravimetric technique has apparent advantages over the conventional drying-weighing method, especially in the determination of brain water in small samples of brain. The value of specific gravity (SG) is not a direct measure of water, and some of the factors that affect SG, such as the composition of edema (4) and the cerebral blood volume (CBV) (1) have recently been analysed. In addition, fundamental technical considerations such as linearity of the gradient column and optimisation of measuring conditions must first be satisfied. After establishing the technical bases in this study, the effect of CBV on SG has been investigated. In comparison with the gravimetric technique, the drying-weighing method has further been analysed, yielding a different nature of error factors in both methods.