Acquired hydrocephalus. IV. Determination of the absorption rate of albumin from the cerebrospinal fluid.

By quantitative isotope ventriculography (QIV), the absorption rate (lambda 2) of albumin in the cerebrospinal fluid (CSF) was determined. Regard was paid to the rate constants for the exchange of the albumin molecule between the serum and extravascular phase. The rate constant lambda 2 and mean biological transit time Tmb-2 were determined in 22 patients suspected of acquired hydrocephalus. QIV revealed that 8 patients were hydrocephalic, while 13 were non-hydrocephalic, and the findings were uncertain in one. In the patients with acquired hydrocephalus, it was demonstrated that lambda 2 and Tmb-2 were significantly reduced as compared with the non-hydrocephalic patients. By means of QIV, a curve was calculated and plotted for the biological decay from the head--the retention curve. From the initial slope of this curve (0--24 hours), the rate constant lambda 2 was calculated. A comparison of lambda 4 and lambd 2 revealed a highly significant correlation, which means that the retention curve gives an acceptable measure of the absorption rate of CSF-albumin.