[Quantitative serial computed tomography. Kidney and tumors].

Density-time-functions after intravenous contrast medium injections are simultaneously taken by a computer tomograph in the region of the aorta and the cortex of the kidney or the region of the aorta and a tumor respectively. The differential equation system resulting from this is solved explicitly on the basis of a compartment model. The resulting functions are related to the density-time functions. These functions include the constants of distribution velocity and discharge velocity. They are modified by application of an iteration procedure (computer programme) to ensure the adequate correspondence between the curves and the density-time-trends. Between the constants of inversion velocity and eversion velocity of the cortex of the kidney, there is a linear as well as allometric relationship, the correlation amounts to r = 0.99. In the case of all tumors, only an allometric relationship (r = 0.92) could be found as regards the conversion constants.