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[3] [4] On CT scans, leukoaraiosis appears as hypodense periventricular white-matter lesions. [ 5 ] The term "leukoaraiosis" was coined in 1986 [ 6 ] [ 7 ] by Hachinski , Potter, and Merskey as a descriptive term for rarefaction ("araiosis") of the white matter, showing up as decreased density on CT and increased signal intensity on T2/FLAIR ...
The dense MCA sign is often accompanied by other early ischemic changes on CT, including: Loss of gray-white matter differentiation in the MCA territory (insular ribbon sign). [7] Sulcal effacement due to early brain edema. Hypodensity of the lentiform nucleus (basal ganglia involvement of ischemia).
Radiolucency or hypodensity indicates greater passage (greater transradiancy) to X-ray photons [1] and is the analogue of transparency and translucency with visible light. Materials that inhibit the passage of electromagnetic radiation are called radiodense or radiopaque , while those that allow radiation to pass more freely are referred to as ...
The Hounsfield unit (HU) scale is a linear transformation of the original linear attenuation coefficient measurement into one in which the radiodensity of distilled water at standard pressure and temperature is defined as 0 Hounsfield units (HU), while the radiodensity of air at STP is defined as −1000 HU.
White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system. The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons). This myelin is found in almost all long nerve fibers, and acts as an electrical insulation.
CT image showing extensive low attenuation in the right hemispheric white matter due to dilated Type 2 perivascular spaces Axial fat-suppressed T2-weighted MRI image in the same patient as above demonstrating extensive dilated Type 2 perivascular spaces in the right hemisphere Perivascular space is depicted in the inset box.
A first-of-its-kind College Football Playoff officially kicks off Friday at 8 p.m. ET with No. 9 Indiana taking the three-hour-plus drive north US-31 to Notre Dame Stadium looking to upset No. 3 ...
It is known that two parameters of the cortical lesions, fractional anisotropy (FA) and mean diffusivity (MD), are higher in patients than in controls. [28] They are larger in SPMS than in RRMS and most of them remain unchanged for short follow-up periods. They do not spread into the subcortical white matter and never show gadolinium enhancement.