STUDY OF EVOKED CEREBRAL BLOOD FLOW UNDER PHYSIOLOGICAL AND PATHOLOGICAL CONDITIONS

Evoked cerebral blood flow (ECBF) is important for cerebral metabolism and normal brain function. Transcranial Doppler sonography (TCD) enables monitoring of ECBF in the middle and posterior cerebral arteries. Functional magnetic resonance imaging (fMRI) enables approximate measurements of the volume of activated brain tissue. With a combination of TCD and fMRI we could find out what the ECBF per unit of activated brain tissue is and investigate the function of neurovascular units. Hemodynamically important internal carotid artery stenosis can cause impairment of neurovascular unit function. Similar kind of impairment can be seen in migraine patients. So far it is not clear if carotid angioplasty with stenting (CAS) improves the function of the neurovascular unit. Therefore, the aim of our study was to find out if combination of TCD and fMRI enables detection of neurovascular units function in healthy subjects, if patients with hemodynamically important internal carotid artery stenosis have impairment of neurovascular unit function and if this function improves after carotid endarterectomy. The records will be made from 40 patients with hemodynamically important internal carotid artery stenosis before and after CAS and 10 healthy volunteers of similar age, gender and dexterity. During TCD and fMRI the patients will grip their hands with frequency that will be 50 % of the maximal frequency.