[en] To establish data about prevalence, number and topography of ''unspecific'' white matter lesions as seen on MRI, the T2-weighted MRI scans of 83 patients with hyperintense focal white matter changes were reviewed. Patients with known inflammatory central nervous system disease were excluded. There was an approximately linear increase in prevalence and number of lesions with age. Prevalence ranged from 18% in the third decade to over 90% in those over 70 years. We found a close correlation with concomitant periventricular hyperintensity. However, rating of Virchow-Robin spaces did not correlate with the number of white matter lesions. Both hemispheres were involved nearly equally with a minimal non-significant right side preponderance. Lesions showed a strong predilection for the frontal and parietal paraventricular ''watershed'' areas. (orig.)