Purpose: The aim of the present study was to validate a simple MRI-procedure for semiquantitative assessment of regional cerebral blood flow. Materials and methods: Unilateral cerebral ischaemia (30 minutes) in the territory of the middle cerebral artery was induced in 14 anesthetised rats. The MRI-experiment consisted in an intravenous bolus injection of gadolinium-DTPA, recording of the cerebral contrast kinetics with a T-2*-weighted pulse sequence, and measurement of the maximal concentration change at a chosen reference point of time. To measure perfusion quantitatively, a microsphere technique, an accepted reference technique was used. With both methods a perfusion index related to the contralateral side was calculated. Results: In all cases decreased perfusion was detected by the MRI technique. The perfusion indices correlated with a coefficient of correlation of r=0.89 (p<0.001). Conclusion: The results demonstrate that contrast-enhanced MRI with bolus injection can be implemented with clinical potential as a semiquantitative instrument for the assessment of cerebral perfusion. Regional cerebral blood volume and collateral blood flow may interfere with the estimate of blood flow.