UBO is the focal area of white matter brain abnormality visualized on T2-weighted MRI scans. They are non-contrast enhancing areas of increased signal intensity. UBOs will appear like demyelinating or dysmyelinating disease on MRI and as structurally distinct lesions on diffusion tensor imaging (DTI) as well as MR Spectroscopy (MRS). Most UBOs are found in the basal ganglia but may also be found in the cerebral hemispheres, brainstem, cerebellum, and thalamus. UBOs are also commonly referred to as white matter hyperintensities (WMHs) due to their bright-white appearance on T2 MRI scans and have also been termed as leukoaraiosis (referring to white matter rarefication).
Underlying vascular mechanisms are suspected. Hypertension, smoking, diabetes, migraine, and heart disease are all risk factors for leukoaraiosis. UBOs/WMLs tend to occur more with age. Histologically, the...