OBJECTIVE: We focused on cerebral imaging findings in a large cohort of young patients with a symptomatic ischemic cerebrovascular event (CVE) to extract relevant pathophysiologic and clinical information.

METHODS: We analyzed the scans of 2,979 patients (aged 18-55 years) enrolled in the sifap1 project with clinical evidence of ischemic stroke (IS) or clinically defined TIA in whom MRI, including diffusion-weighted imaging, was obtained within 10 days of the CVE. Age groups were categorized as 18-34, 35-44, and 45-55 years. We compared age- and sex-specific proportions of infarct features, white matter hyperintensities, and old microbleeds.

RESULTS: Acute infarcts were identified in 1,914 of 2,264 patients (84.5%) with IS and 101 of 715 patients (14.1%) with TIA. Among patients with IS, younger age was significantly associated with acute infarcts in the posterior circulation, while anterior circulation infarcts and acute lacunar infarcts were more frequent in older age groups. One or more old infarcts were present in 26.8% of IS and 17.1% of TIA patients. This rate remained high even after excluding patients with a prior CVE (IS, 21.7%; TIA, 9.9%). The prevailing type of old infarction was territorial in patients younger than 45 years and lacunar in those aged 45 years or older. The frequency of white matter hyperintensities (46.4%) and their severity was positively associated with age. Old microbleeds were infrequent (7.2%).

CONCLUSIONS: Young adults show a high frequency of preexisting and clinically silent infarcts and a relative preference for acute ischemia in the posterior circulation. Findings suggesting small-vessel disease become apparent at age 45 years and older.