Picturing Multiple Sclerosis: Conventional and Diffusion Tensor Imaging

Robert Fox
2008 Seminars in neurology  
Magnetic resonance imaging (MRI) has provided an unparalleled window into understanding multiple sclerosis (MS). Through recognition of relatively specific characteristics of MS, MRI has become an integral part of patient initial evaluation and longterm management. MRI has now been integrated into the formal diagnostic criteria, whereby new lesions can fulfill either dissemination in space or dissemination in time criteria. Long-term MS therapies significantly reduce the development of new
more » ... ns as measured by MRI, and clinical trial methodology now routinely uses MRI as the primary outcome in Phase I/II MS trials. Despite the advantages provided by MRI, conventional imaging indicates only the presence of injury to the central nervous system, providing little information on either the severity of injury or its later recovery. Several advanced imaging methodologies such as diffusion tensor imaging (DTI) provide a greater dynamic range for evaluating tissue integrity. DTI has provided useful insights into the pathogenesis of MS, both within lesions as well as within the white matter which appears normal on conventional imaging. Evidence from animal models suggests that DTI may differentiate axonal injury from demyelination and therefore may be useful in the evaluation of neuroprotective therapies. Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease affecting the brain, spinal cord, and optic nerves. Originally described through pathological studies by Charcot in the nineteenth century, it wasn't until the development of advanced imaging techniques that the full extent and recurrent nature of MS was appreciated, particularly at the early stages of disease. The hallmark of MS is recurrent demyelination of the central nervous system (CNS), disseminated in space and time. The original diagnostic criteria relied exclusively on clinical relapses to fulfill the dissemination requirement, but more recent diagnostic criteria integrate imaging into the formal diag-nostic process. Multiple sclerosis causes characteristic changes on brain and spine imaging, and these characteristics can be helpful in differentiating MS from other disorders. Many imaging reports of MS will list demyelination in the differential diagnosis of any scan with T2 lesions, regardless of lesion characteristics and location. A greater appreciation of the classic imaging characteristics of MS and their relevance to the disease process can help the clinician in both the accurate diagnosis and successful management of patients with MS. This article will discuss the different imaging characteristics of MS and their relevance to its diagnosis and long-term management.
doi:10.1055/s-0028-1083689 pmid:18843574 fatcat:qfz4uhjqqfcxbnoc7gu3xhczdy