Abstract: A method and system for evaluating the cerebral circulation of a patient is described. The arterial network of the brain is partitioned into a plurality of different regions where each region is supplied with blood by particular cerebral arteries. Volume flows into the regions are calculated from the measured volume flows of the cerebral arteries using quantitative magnetic resonance angiography. The cerebrovascular circulation of an individual patient may therefore be evaluated for the presence of disease by comparing the regional blood flows of the patient to normal values as obtained from population data.