NONINVASIVE QUANTIFICATION OF REGIONAL CE REBRAL BLOOD-FLOW AND BLOOD-VOLUME WITH DYNAMIC MR-IMAGING - PRELIMINARY-RESULTS IN VOLUNTEERS AND PATIENTS WITH CEREBROVASCULAR DISORDERS

Purpose: A non-invasive MR-method for the quantification of regional c erebral blood flow (rCBF) and blood volume (rCBV) is used to examine h ealthy volunteers and patients with cerebrovascular disorders. Materia ls and methods: 20 healthy volunteers and 10 patients with severe cere brovascular disorders were examined, MR imaging was performed on a 1.5 T imaging system. Before, during and following brief antecubital vein bolus injection of Gd-DTPA, a series of 32 rapid T2-weighted gradien t echo images of two different slices were simultaneously acquired in order to measure the concentration-time-curves in the brain tissue and the arterial input function in the brain feeding arteries, From these series of images the concentration-time-curves were computed. Princip les of indicator dilution analysis were applied to compute rCBF and rC BV. The volunteers underwent one examination each. All patients underw ent two examinations, one before and the second after azetazolamide st imulation. Results: In volunteers the measured rCBF and rCBV values ar e in good agreement with data from positron emission tomography studie s, In patients with cerebrovascular disorders in the asymptomatic hemi sphere a mean increase of rCBF of 43,45 +/- 18,04 % was observed after azetazolamide stimulation. In the affected areas of the symptomatic h emisphere in 8 from 10 patients the acetazolamide test reveals a signi ficantly reduced response to azetazolamide stimulation, indicating an exhausted cerebrovascular reserve capacity. Conclusion: Dynamic MR-Ima ging can provide quantitative information about rCBF and rCBV. In pati ents with cerebrovascular disorders, this method can be applied to est imate the cerebrovascular reserve capacity.