Figure 1

Example of intracranial blood pressure-dependent flow velocity changes. (a) M1-MCA segment (b) P3-PCA segment. Placement of the Doppler sample volume is marked by red circles in the original colour-mode image and in a corresponding schematic drawing (right). The white dotted lines indicate the location of the midbrain. The individual systolic flow velocities at the above blood pressure values were for the MCA (a): 125 mmHg - 28/21 cm/s; 150 mmHg - 39/26 cm/s; 165 mmHg - 45/26 cm/s and for the PCA (b): 100 mmHg - 81/31 cm/s; 125 mmHg - 96/38 cm/s; 150 mmHg - 119/46 cm/s.