Purpose: To determine the prevalence and anatomic characteristics of infarctlike lesions seen on cranial magnetic resonance (MR) images.
Materials and methods: The study cohort consisted of 5,888 community-living individuals aged 65 years and older enrolled in a longitudinal, population-based study of cardiovascular disease. MR images were obtained from 3,658 participants and evaluated by trained readers. Lesion size, anatomic location, and signal intensity were recorded. Infarctlike lesion was defined as a nonmass, hyperintense region on spin-density- and T2-weighted images and, in cerebral white matter and brain stem, a hypointense region on T1-weighted images.
Results: Infarctlike lesions were depicted on MR images of 1,323 (36%) participants. Eighty-five percent (1,128 participants) had lesions 3 mm or larger in maximum dimension, although 70.9% (1,320 of 1,861) of these lesions were 10 mm or less. Lesion prevalence increased with age, especially with lesions 3 mm or larger, which increased from 22.1% (86 of 389) in the 65-69-year age group to 42.9% (88 of 205) in the over-85-year age group (P < .0001). Lesion prevalence was slightly greater in men (497 of 1,527 [32.5%]) than in women (631 of 2,131 [29.6%]), but did not differ between blacks and non-blacks. The deep nuclei were the most commonly affected anatomic sites, with 78.2% (1,451 of 1,856) of lesions. Lesions that involved the cerebrum and posterior fossa accounted for 11.7% (218 of 1,856) and 10.1% (187 of 1,856) of lesions, respectively.
Conclusion: If the lesions reported in this study indicate cerebrovascular disease, subclinical disease may be more prevalent than clinical disease, and the prevalence of disease may rise with age. Also, infarctlike lesions have a distinctive anatomic profile.