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[Neuroradiological aspects of encephalitis disseminata]
W Reiche1, S Merkelbach, W Reith
1Abteilung für Neuroradiologie der Radiologischen Klinik, Universitätskliniken des Saarlandes, Homburg/Saar. nrwrei@med-rz.uni-saarland.de
Abstract:
Magnetic resonance imaging (MRI) has developed without doubt to the most important investigation method in multiple sclerosis. MRI is very sensitive to detect MS lesions but unfortunately of limited specificity. The purpose of this review is 1. to work up the MRI characteristics of MS lesions, 2. to derive recommendations for MRT-protocolls for daily radiological work and 3. to discuss new MR developments. MS lesions in the acute inflammatory stage show first an enhancement of GD-DTPA due to break down of the blood brain barrier and develop a T2-hyperintensity due to an edema. The following disease course is categorized in a phase of reparation and remyelinisation respectively, of gliosis and a defect stage. MS-plaques in the remyelinisation and gliotic phase appear as hyperintens lesions on T2-weighted scans. Chronic MS lesions with a defect are also T2-hyperintens and demonstrate additionally due to severe axonal loss a hypointensity on short TR SE scans. MS lesions exhibit a characteristic distribution. They are found typically periventricular, in the corpus callosum and at the calloso-septal interface, cortico-subcortical and infratentorial. The most important MR criteria to predict conversion from suspected (CSMS) to clinical definite MS (CDMS) are GD-DTPA enhancement and juxtacortical lesion localisation followed by the parameter periventricular and infratentorial localisation. Based on guidelines for the use of MRI in drug studies and on equivalent recommendations for the routine diagnostic we suggest rational and economic MRT protocols for cerebral, spinal, and N. opticus investigations. Such standardised protocols shall help to make MRI investigations more efficient and better comparable. New MR developments include measurement of magnetisation transfer and T2-relaxation, diffusion weighted imaging, proton MR spectroscopy, and quantification of lesion load. These methods can analyse more specifically tissue changes in MS plaques and yet can reveal changes in normal appearing white matter.
Insights
Magnetic resonance imaging (MRI) is crucial for multiple sclerosis (MS) diagnosis, offering high sensitivity but limited specificity. This review details MS lesion characteristics, recommends MRI protocols, and explores new developments for improved specificity and tissue analysis.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Context:
- Multiple sclerosis (MS) diagnosis heavily relies on magnetic resonance imaging (MRI).
- MRI demonstrates high sensitivity for detecting MS lesions but faces challenges with specificity.
- Understanding MRI characteristics is vital for accurate MS assessment and management.
Purpose:
- To delineate the specific MRI characteristics of multiple sclerosis lesions.
- To establish evidence-based recommendations for MRI protocols in routine radiological practice.
- To review and discuss emerging advancements in MRI technology for MS investigation.
Summary:
- MS lesions exhibit distinct MRI features based on disease stage: acute inflammatory lesions show contrast enhancement (GD-DTPA) and T2-hyperintensity (edema); reparative/gliotic phases present as T2-hyperintense lesions; chronic lesions with axonal loss appear T2-hyperintense with short TR SE hypointensity.
- Characteristic lesion distributions include periventricular, corpus callosum, calloso-septal interface, cortico-subcortical, and infratentorial regions.
- Key MRI criteria for predicting conversion from suspected to definite MS include GD-DTPA enhancement, juxtacortical, periventricular, and infratentorial lesion locations.
Impact:
- Standardized MRI protocols enhance diagnostic efficiency and comparability across different centers.
- Advanced MRI techniques like magnetization transfer, T2-relaxation, diffusion-weighted imaging, MR spectroscopy, and lesion load quantification offer more specific tissue change analysis.
- These novel methods can detect subtle changes in normal-appearing white matter, potentially improving early diagnosis and monitoring of MS progression.