Characteristic values of MR examinations of cerebral perfusion with high spatial and temporal resolution

Purpose: Different parameters for the evaluation of perfusion studies with dynamic MR-measurements after the administration of paramagnetic contrast a gent were compared. Method: An echo planar imaging (EPI) sequence was devel oped that allows dynamic multi-slice data acquisition. Evaluations of the m easurements were performed by calculating parameter maps. Phenomenological quantities such as maximal signal reduction and time to peak as well as der ived quantities such as approximations of the regional cerebral blood volum e were used as parameters. Patients with a low grade astrocytoma, with an a cute cerebral infarction and with stenoses of the carotid arteries were exa mined. Results: On comparison of the derived parameters with the phenomenol ogical parameters no major differences were found in qualitative comparison s of the parameter maps. The comparison of relative parameter values in sel ected regions within the datasets of 20 patients show a high correspondence between phenomenological and derived parameter values. Conclusions: Using EPI measurement techniques with high temporal resolution, parameter maps of simple values like maximal signal reduction and time-to-peak are sufficien t to visualize relative differences of perfusion within the selected slices . However, the calculation of relative rCBV and rCBF values might be helpfu l for the detailed characterization of signal courses in selected regions.