Chapter 12 Susceptibility weighted imaging in multiple sclerosis

Multiple sclerosis (MS) is a disease of the central nervous system characterized by widespread demyelination, axonal loss, gliosis, and neurodegeneration. Susceptibility weighted imaging (SWI) is a relatively simple magnetic resonance imaging application that can directly image cerebral veins by exploiting venous blood deoxyhemoglobin. It uses phase information to enhance T2* contrast by using a mask determined from the local susceptibility. With the advent of parallel imaging and the greater availability of clinical 3T MR scanners, it is now possible to image the entire brain with SWI in roughly 4minutes. SWI has been found to provide clinically useful information that is often complementary to conventional MR imaging sequences. SWI has also given rise to emerging biomarkers for MS pathology such as the central vein sign and paramagnetic rim lesions that can accurately differentiate MS from other diseases and, hence, can improve MS diagnosis. In this chapter, we cover the use of SWI, fluid-attenuated inversion recovery, quantitative susceptibility mapping, strategically acquired gradient echo, and microscopic in vivo contrast revealed origins imaging and their associated biomarkers to study MS lesions and their tissue properties.