[Noninvasive quantification of cerebral blood volume and blood flow with dynamic MR tomography. Studies of probands and patients with cerebrovascular insufficiency].

PURPOSE

A non-invasive MR-method for the quantification of regional cerebral blood flow (rCBF) and blood volume (rCBV) is used to examine healthy volunteers and patients with cerebrovascular disorders.

MATERIALS AND METHODS

20 healthy volunteers and 10 patients with severe cerebrovascular 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 gradient echo images of two different slices ere simultaneously acquired in order to measure th 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. Principles of indicator dilution analysis were applied to compute rCBF and rCBV. The volunteers underwent one examination each. All patients underwent two examinations, one before and the second after azetazolamide stimulation.

RESULTS

In volunteers the measured rCBF and rCBV values are in good agreement with data from positron emission tomography studies. In patients with cerebrovascular disorders in the asymptomatic hemisphere a mean increase of rCBF of 43,45 +/- 18.04% was observed after azetazolamide stimulation. In the affected areas of the symptomatic hemisphere in 8 from 10 patients the acetazolamide test reveals a significantly reduced response to azetazolamide stimulation, indicating an exhausted cerebrovascular reserve capacity.

CONCLUSION

Dynamic MR-Imaging can provide quantitative information about rCBF and rCBV. In patients with cerebrovascular disorders, this method can be applied to estimate the cerebrovascular reserve capacity.