The study of cerebral venous blood flow disturbance peculiarity in the norm and under the extravasal compression of brachiocephalic veins with the use of magnetic resonance venography and ultrasound duplex scanning

The MR-venography of the veins and brain venous sinuses, brachiocephalic veins an internal jugular veins duplex scanning have been performed in order to study the distinctions of cerebral venous hemodynamics of healthy people and the patients with venous encephalopathy caused by the extravasal compression of the brachiocephalic veins at the neck level and the superior sections of mediastinum. It has been revealed that the blood flow reducing in transverse brain sinuses occurs not only in the case of outflow disorder in the distal sections of the venous system, but also in norm. This reducing depends on anatomic constitution of confluens sinuum and the venous angle type of brachiocephalic veins. The three venous angle types of brachiocephalic veins have been distinguished: y-type, mu-type and Y-type. It has been registered that in case of the mu-type angle the blood flow can be reduced in norm due to peripheral resistance increase at the physiological bends of nearly a right angle type. The distinctions of hemodynamics in case of venous obstruction in contrast to arterial obstruction have been described. It has been registered that in case of outflow trouble in one of the internal jugular veins the speed and the volume of the blood flow in it are progressively reduced depending on the duration and the manifestation of compression. All this results in narrowing of the vein diameter from the affected side, and in compensatory distention of the diameter and increase of blood flow volume in the contralateral internal jugular vein, vertebral and external jugular veins, in succession.