الفهرس 
introduction and aim of workOnly 14 pages are availabe for public view
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Abstract
One of the most common questions in daily radiological practice, when we see multiple white matter lesions, ’Do we have to think of Multiple Sclerosis or vascular disease, for instance in a hypertensive patient or vasculitis? In order to be able to answer that question, we have to realize that when we study white matter lesions (WMLs): Many neurological diseases can mimic MS both clinically and radiologically. Most incidentally found WMLs will have a vascular origin. The list of possible diagnoses of WMLs is long. A stroke is the rapid developing loss of brain function(s) due to disturbance in the blood supply to the brain. This can be due to ischemia (lack of blood supply) caused by thrombosis or embolism or due to a hemorrhage. The ischemic penumbra is defined as the functionally compromised, but structurally intact tissue surrounding a core of infarcted area. Multiple sclerosis (MS) is the most common inflammatory demyelinating disease of the central nervous system in young and middle-age adults, but also affects older people. It is an autoimmune disease in which body’s immune response attacks and damages the myelin. When myelin is lost, the axons can no longer effectively conduct signals. Diffusion Weighted Imaging is an MRI-based imaging modality that measures the free diffusion of water molecules (Brownian motion) enabling the detection of imaging information beyond the resolution of conventional MRI techniques. Diffusion weighting enables one to distinguish between rapid diffusion of protons (unrestricted diffusion) and slow diffusion of protons (restricted diffusion). The ADC maps are used to exclude (T2 shine through) as the cause of increased signal on DWI. MR spectroscopy (MRS) is a non-invasive means of obtaining metabolic information. It enables tissue characterization on a biochemical level and detection of metabolic abnormalities. During the first 2 weeks after onset of disease , the diffusion can be used as a reliable tool by using the ADC values which is above normal in multiple slerosis and below normal in cerebral infarction before pseudonormalization. MRS also assisst differentiation as well as staging of the disease through different metabolic patterns. Both MRS and diffusion are comlemetary in this issue. Differentiation can be summarized in the following tables: MR diffusion and MRS should be performed in any controvrsal case of hyperintense white matter lesions. Never use diffusion map intensity , because both lesions appear hyperintense, dt T2 shine-through effect. (Can be eliminated by using ADC maps).