We performed rapid sequential CT scanning following iv injection of a bolus of contrast medium and generated three functional images relating to intravascular circulation time (rABCT), vascular volume (Vv) density and blood-brain barrier (BBB) unidirectional constant uptake rate (Ki), respectively. This was accomplished by calculating the first mathematical moment of the monitored time-density curves about the injection time and from the multiple time graph analysis described by Patlack and co-workers. A satisfactory resolution was achieved, allowing separate appreciation of changes in rABCT both in large vessels and in tissue small vessels. Combined evaluation of rABCT and Vv images allowed us to differentiate between tumors.