[Depiction of evoked regional brain activity using magnetic resonance tomography]

After brief summary of the various parameters determining contrast behaviour in diagnostic magnetic resonance imaging, special attention is paid to recent developments in its application to the study of brain perfusion and oxygenation. With and without extrinsic contrast media, it is now possible to image regional tissue perfusion and brain oxygenation and thus the evoked activation of regions of the brain with a high spatial resolution of about 1 mm and a temporal resolution of about 50 ms. The blood oxygenation dependent magnetic properties of hemoglobin are used as sensitive endogenous indicators of the oxygenation state of blood. In dependence upon evoked local brain activity, contrast changes of up to 30% have already been observed. Possible future developments with respect to the application of MRI to even more complete functional studies of the brain and other organs will be mentioned.