Multiple sclerosis (MS) is the most common demyelinating disease of the central nervous system and the most common cause of non-traumatic neurological disability in young adults. Magnetic resonance imaging (MRI) is the most important paraclinical investigation used in the diagnosis and monitoring of the disease. In the past years, spinal cord MRI has improved significantly and has become an important part of the diagnostic workup for MS. Presently, follow-up imaging of the spinal cord is only performed when spinal cord related symptoms occur. However, there is increasing evidence that asymptomatic spinal cord lesions can occur, independently of brain disease activity. Despite these cord lesions being asymptomatic, they impact disability accrual in the long term. Although this might be an imaging marker for monitoring and treatment, it is not yet applied in the clinical setting. The investigators will prospectively collect spinal cord MRI data (in addition to routine brain MRI), and blood-based biomarkers (plus cerebral spinal fluid markers, if available), in recently diagnosed MS patients, to address the following research questions: * What is the incidence of asymptomatic spinal cord lesions in patients commencing DMT? * And in the absence of radiological progression on brain imaging, how frequently do asymptomatic spinal cord lesions occur? In other words, how often is disease activity solely proven by spinal cord MRI and what is the number-needed-to-scan? * A secondary objective is to investigate which patients are predisposed to developing new spinal cord lesions during follow-up in the early stages of the disease. For this question, factors such as cerebrospinal fluid (CSF) profiles, B-cell composition in blood, soluble blood markers, and clinical features will be focused on.