Leukoaraiosis

[1][2] On MRI, leukoaraiosis changes appear as white matter hyperintensities (WMHs) in T2 FLAIR images.

[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 sequences (white matter hyperintensities) performed as part of MRI brain scans.

Hypertension, smoking, diabetes,[3] hyperhomocysteinemia, and heart diseases are all risk factors for leukoaraiosis.

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.

Axial T2 FLAIR sequence MR image of a middle-aged man with leukoaraiosis.
MRI image: Leukoaraiosis in a 90-year-old patient with cerebral atrophy.
Head CT showing periventricular white matter lesions.
The blue arrows indicate leucoaraiosis. In the left image these may well represent transependymal CSF diapedesis due to normal pressure hydrocephalus , which in turn is suggested by the narrowed superior CSF spaces and acute callosal angle. The unilateral occurrence of these alterations in right image suggests they are probably due to vascular encephalopathy.