The Role Of Mri In Understanding Ms Pathophysiology

Tcuadro Clinico Tumores Cerebrales

CMRI is not only important for diagnosing MS but also in giving clues about MS pathophysiology, as outlined by the following findings 1. The patterns of MRI activity vary significantly in individual patients over time, from one patient to another, and across the different clinical pheno-types of MS. Disease activity tends to decline with patients' age (105) and is very low in patients with PPMS (106,107). 2. The harvest of enhancing MS lesions can be markedly increased when administering a TD...

Introduction

Multiple sclerosis (MS) is the most common chronic inflammatory-demyelinating disease affecting the central nervous system (CNS) of young adults in the western countries, leading, in the majority of cases, to severe and irreversible clinical disability (1). Since its clinical introduction, conventional magnetic resonance imaging (cMRI-dual-echo and postcontrast Tl-weighted scans) has greatly improved our ability to diagnose MS and to monitor its evolution, either natural or modified by...

The Active MS Lesion

On gross inspection, the active MS plaque appears as a cheesy soft area of irregular pink or gray color. Microscopically, active inflammatory demyelination is characterized by an intimate admixture of lipid-laden macrophages and large reactive astro-cytes, accompanied by variable perivascular inflammation. The involved areas demonstrate marked pallor of myelin staining with relative preservation of axons, although where damage is most severe, axons may be lost or fragmented and display...

References

The prevalence of multiple sclerosis in the world an update. Neurol Sci 2001 22(2) 117-139. 2. Jersild C, Fog T, Hansen GS, et al. Histocompatibility determinants in multiple sclerosis, with special reference to clinical course. Lancet 1973 2(7840) 1221-1225. 3. Ebers GC, Sadovnick AD, Risen NJ. Canadian Collaborative Study Group. A genetic basis for familial aggregation in multiple sclerosis. Nature 1995 377(6545) 150-151. 4. Sadovnick AD, Armstrong H, Rice G, et al. A...

Humoral Immunity As Indirect Evidence For Autoimmunity In Ms

The humoral arm of the immune system has been implicated in the pathogenesis of MS. The findings of oligoclonal bands (OCBs) and increased levels of intrathecal immunoglobulins (Igs) in more than 90 of MS patients strongly suggest involvement of B-cells in MS. The Igs found in MS CSF include IgG, IgA, IgM, and IgD (92). B-cells, plasma cells, and Ig are typically present in MS lesions, and at times have been identified in normal-appearing white matter of MS patients (93,94). Even in the very...

Brief Review Of Basic Aspects Of Nonconventional Mr Techniques

Magnetisation Transfer Weighted Images

MT MRI is based on the interactions between protons in a relatively free environment and those where motion is restricted. Off-resonance irradiation is applied, which saturates the magnetization of the less mobile protons, but this is transferred to the mobile protons, thus reducing the signal intensity from the observable magnetization. Thus, a low MT ratio (MTR) indicates a reduced capacity of the macromol-ecules in the CNS to exchange magnetization with the surrounding water molecules,...

Somatosensory Symptoms

Sensory complaints are frequent among the earliest symptoms of MS with a recent survey indicating that they were the first manifestation in 43 of patients, but this figure may have included visual as well as somatosensory phenomena (47). The symptoms are often perplexing for the clinician, especially during the onset bout, because they are frequently unassociated with objective signs on the neurological examination. In addition, the anatomical distribution is often peculiar, not corresponding...

Neuromyelitis Optica Devic Disease

Neuromyelitis Optica

NMO is an idiopathic inflammatory CNS demyelinating disease characterized by either monophasic or relapsing attacks of optic neuritis and myelitis. Pathologically, NMO lesions demonstrate extensive demyelination across multiple spinal cord levels, associated with necrosis and cavitation, as well as acute axonal damage in both gray and white matter. There is a pronounced loss of oligodendrocytes within the lesions, and inflammatory infiltrates are comprised of large numbers of macrophages...

The Chronic Inactive MS Lesion

Multiple Sclerosis Lesions

The MS lesion may evolve differently during early and chronic phases of the disease. Different stages and types of demyelinating activity can be identified within these phases. Most neuropathological studies of MS are based on tissue from individuals with long-standing disease. Pathologically, these late chronic cases are characterized by the presence of multiple sharply demarcated plaques of demyelination typically ranging from lt 1 mm to several centimeters in size. Plaques are present in...

Types of MS Lesions

Lesion Medicale

On the basis of topographical distribution of macrophages, and the type of myelin degradation products present within the macrophage, four types of MS plaques can be distinguished Figure 4 . The acute active plaque'' is characterized by the presence of macrophages containing early and late myelin degradation products, distributed throughout the extent of the lesion. The radially expanding ''active rim'' shows the accumulation of numerous macrophages, containing both early and late myelin...