what is foci
What is foci on an MRI? A: 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. Keep Learning.