Prevalence of intracranial artery stenosis in a general population using 3D-time of flight magnetic resonance angiography.

BACKGROUND:Data on prevalence of intracranial artery stenosis (ICAS) in Western populations is sparse. The aim of the study was to assess the prevalence and risk factors for ICAS in a mainly Caucasian general population. METHODS:We assessed the prevalence of ICAS in 1847 men and women aged 40 to 84 years who participated in a cross-sectional population-based study, using 3-dimensional time-of-flight 3 Tesla magnetic resonance angiography. ICAS was defined as a focal luminal flow diameter reduction of ≥50 %. The association between cardiovascular risk factor levels and ICAS was assessed by multivariable regression analysis. RESULTS:The overall prevalence of ICAS was 6.0 % (95 % confidence interval (CI) 5.0-7.2), 4.3 % (95 % CI 3.1-5.7) in women and 8.0 % (95 % CI 6.3-10.0) in men. The prevalence increased by age from 0.8 % in 40-54 years age group to 15.2 % in the 75-84 years age group. The majority of stenoses was located to the internal carotid artery (52.2 %), followed by the posterior circulation (33.1 %), the middle cerebral artery (10.8 %) and the anterior cerebral artery (3.8 %). The risk of ICAS was independently associated with higher age, male sex, hypertension, hyperlipidemia, diabetes mellitus, current smoking and higher BMI. CONCLUSIONS:The prevalence of ICAS in a general population of Caucasians was relatively high and similar to the prevalence of extracranial internal carotid artery stenosis in previous population-based studies.