Neuroimaging of Multiple Sclerosis: An Update

Conventional magnetic resonance imaging (MRI) techniques have become an important tool for supporting a diagnosis of multiple sclerosis (MS), for ruling out MS mimickers, and for monitoring disease evolution in clinical trials. MRI is able to demonstrate spatial and temporal dissemination of demyelinating plaques in the brain and spinal cord and is able to detect clinically silent lesions. This is why MRI is integrated in the diagnostic scheme of MS and used to monitor treatment efficacy in clinical trials. Although conventional MRI is an important tool in the diagnosis and management of MS, the ability of conventional MRI techniques to accurately assess inflammatory and neurodegenerative changes is limited. To increase the detection of cortical lesions, the three-dimensional double inversion recovery imaging (3D-DIR) is probably the most effective technique today. Other 3D sequences using high-resolution T1-weighted images, such as T1-weighted 3D-spoiled gradient-recalled-echo (SPGR) [24], T1-weighted phase-sensitive inversion recovery (PSIR) [25], or 3D magnetization-prepared rapid acquisition gradient echo (MPRAGE) [26], also allow the detection of cortical lesions and their classification as purely intracortical, mixed GM and WM, or juxtacortical. These sequences have high spatial resolution and contrast between GM and WM and provide a clearer delineation of the GM-WM boundary than DIR sequences. Lesions appear hypointense on these T1 sequences.