Foci on an MRI are periventricular white matter lesions, evidence of changes in a patient's brain that appear on the MRI as white spots, states Timothy C. Hain, M.D. From one-third to 80 percent of MRI scans performed on patients older than 65 show T2 hyperintense foci as of 2015.
Periventricular white matter lesions have various causes, such as the normal aging process. In these cases, the spots are called unidentified bright objects. Other causes include multiple sclerosis-related disorders, minor strokes and vitamin B6 deficiency, notes Dr. Hain, a Chicago-based neurologist. Patients who have the lesions display symptoms of impaired balance, a slower walk and reduced mental abilities. Treatments for the condition include taking vitamin supplements and controlling hypertension.