Assessment of cerebral hemodynamics and tissue perfusion in Multiple Sclerosis patients

Abstract

• Cerebral blood flow will be maintained near the desired set point values by autonomic and neurocardiogenic system with regulation of vascular, neuronal and humoral mechanisms after changing from supine to upright position. • TCCD is a non-invasive ultrasound procedure to evaluate the changes in CBFV. Evaluation of the reduction in CBFV by TCCD, after changing from supine to upright position, may provide information about cerebral autoregulation. • Cerebrovascular reactivity synthetizes the compensatory ability of cerebral vasculature to adequate blood flow and preserve perfusion through the vasodilatation of arterioles in response to vasoactive stimuli. • The pathophysiology of hemodynamic impairment in MS patients is reasonably multifactorial and, at least partly, secondary to the downstream effects of the neuro-inflammatory cascades. The changes of endothelial cells induced by inflammatory cytokines and oxidative stress compromise chemoreception and control of vascular tone. • The chronically high levels of vasoactive mediators like nitric oxide can sustain vasodilation, desensitize smooth muscle, induce vascular habituation and, hence, prevent small vessels to further dilate when vasoactive triggers occur.