The second part of a review article devoted to a detailed consideration of the issues of diagnostic semiotics of acute disorders of cerebral circulation using CT and MR perfusion study techniques. We consider the physiological aspects of formation of the basic parameters of tissue perfusion: of cerebral blood Șow (CBF), cerebral blood volume (CBV), mean transit time (MTT) and time to peak (TTP) contrast, as well as patterns of pathological changes in these parameters (hypo-, hyper- and aperfusion), developing in various degrees of brain ischemic damage and penumbra areas. It is noted that the improvement of MRI using for tissue classi⠇cation of perfusion-diநusion (PWI/DWI) mismatch has a better chance of primary development due to the fact that it non-radiation exposure and is not connected with the need to introduce a large contrast volume, and with the introduction of non-contrast arterial spin labeled technique (ASL). Variants of events in the dynamics of perfusion as a result of reperfusion therapy. There were discussed the problems limiting the use of perfusion techniques in clinical practice.

The cerebral venous congestion is the primary factor in damaging the brain with cerebral venous thrombosis. Ischemia in stroke associated with cerebral venous sinusthrombosis (CVST) is secondary, developing as a result of externally induced constriction of the blood vessels feeding the area of stasis in vasogenic edema, which leads to necrosis is less likely than with arterial ischemic stroke. Stroke associating CVST more often accompanied by hemorrhagic transformation than atherothrombotic. Venous congestion is detected in cardioembolic stroke in the perifocal zone of the ischemic focus, and probably plays a role in the courses and outcomes of stroke, contributing to the development of vasogenic edema and early secondary hemorrhage. Identify venous stasis in principle possible using the technique of determining the ultrasound index arteriovenous ratio and sighting in the ischemic focus and perifocal zone as hyperperfusion using perfusion techniques MSCT or MRI of the brain.

Purpose. The study was aimed at detecting the signs of focal and perifocal injury in venous strokes and their differences from those in arterial strokes by urgent CT and MRI. Materials and methods. The diagnosis of a venous stroke was verifi ed by neurovisualization (native MSCT, perfusion CT or CT angiography, conventional MRI and MR-angiography) and during autopsy (in case of a fatal outcome). Results. Patients with venous strokes had a hyperdense (by routine CT) stroke-related vessel, compensatory venous distention on the side of the occlusion, early haemorrhagic transformation, the changes localized in the region of the affected vein. Conclusions. The study allowed to detect CT and MRI signs, which can help to differentiate arterial and venous strokes.