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Leukoaraiosis is a particular abnormal change in appearance of white matter near the lateral ventricles. It is often seen in aged individuals, but sometimes in young adults. On MRI, laukoaraiosis changes appear as white matter hyperintensities (WMHs) On CT scans, laukoaraiosis appears as hypodense periventricular white-matter lesions.
Contents
The term leukoaraiosis was coined in 1986 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 sequences (white matter hyperintensities) performed as part of MRI brain scans.
These white matter changes are also commonly referred to as periventricular white matter disease, or white matter hyperintensities (WMH) due to their bright white appearance on T2 MRI scans. Many patients can have leukoaraiosis without any associated clinical abnormality. However, underlying vascular mechanisms are suspected to be the cause of the imaging findings. Hypertension, smoking, diabetes, hyperhomocysteinemia, and heart disease are all risk factors for leukoaraiosis.
Leukoaraiosis has been reported to be an initial stage of Binswanger's disease but this evolution does not always happen.
Causes
White matter hyperintensities can be caused by a variety of factors including ischemia, micro-hemorrhages, gliosis, damage to small blood vessel walls, breaches of the barrier between the cerebrospinal fluid and the brain, or loss and deformation of the myelin sheath. Multiple small vessel infarcts in the subcortical white matter can cause the condition, often the result of chronic hypertension leading to lipohyalinosis of the small vessels. Patients may develop subcortical dementia syndrome.