Perfusion MR I.

There has been an increasing interest in studying microvascular and brain perfusion abnormalities in multiple sclerosis (MS) due to the accumulating evidence regarding the primary vascular pathogenesis in MS [1-4]. Early microscopic investigations demonstrated perivascular inflammatory infiltrates, including macrophages, often found in close contact with the disintegrating myelin sheath [5], which were later described as a T-cell-mediated immune reaction causing the activation of macrophages that contained intracytoplasmic, myelin-reactive degradation products [6]. The intravascular fibrin deposition [7, 8] and venous occlusive changes with hemodynamic impairment have also been demonstrated in active MS lesions [9]. Therefore, not surprisingly, these essential vascular pathologies have effects on the cerebral blood perfusion, which may cause mitochondrial dysfunction and axonal degeneration. However, only recently, due to the major achievements of in vivo perfusion imaging, have we started to understand the mechanisms of hemodynamic changes and neurodegeneration occurring in MS. This chapter focuses on some of the recent developments in the field of vascular pathology and on some ongoing research using perfusion MRI, particularly dynamic susceptibility contrast-enhanced MRI (DSC-MRI), to investigate vascular neuropathology in MS. [ABSTRACT FROM AUTHOR]