NEFL and Atrophy: A long-term follow-up study has found a close correlation between serum NfL levels and MRI lesions and degree of atrophy measured 10 years later (Chitnis et al., 2018), while another found that patients with higher baseline serum NfL levels showed significantly more brain and spinal cord volumes over the 2 and 5 years follow-up (Khalil et al., 2018).