Association of intracranial atherosclerotic stenosis with severity of white matter hyperintensities

Background and purpose White matter hyperintensities ( WMH s) on magnetic resonance imaging ( MRI ) have been linked to small‐vessel disease, but the precise pathogenesis underlying WMH s remains unclear. Studies about an association of WMH s with extracranial atherosclerotic stenosis ( ECAS ) showed conflicting results and the relationship of WMH s with intracranial atherosclerotic stenosis ( ICAS ) is uncertain. Methods A cross‐sectional study of 679 consecutive Korean patients with acute ischaemic stroke (mean age 67.8 ± 12.6; 395 males) who underwent brain MRI /MR angiography was conducted. Severity of deep WMH s (d‐ WMH s, n  = 560) and periventricular WMH s (p‐ WMH s, n  = 590) was rated separately and compared across three groups: ICAS ( n  = 318), ECAS ( n  = 71) and no cerebral atherosclerotic stenosis ( NCAS ) ( n  = 290). Results The ICAS group showed a higher d‐ WMH /p‐ WMH score (1.62 ± 0.85/1.65 ± 0.79) than both the ECAS (1.25 ± 0.87/1.23 ± 0.78) and NCAS (1.19 ± 0.92/1.24 ± 0.81) groups ( P  <   0.001 for all). Patients with a greater number of ICAS were more likely to have higher scores of d‐ WMH /p‐ WMH ( P  <   0.001 for all). Patients with higher scores of d‐ WMH /p‐ WMH had a higher incidence of ICAS ( P  <   0.001 for all), but not of ECAS or NCAS . In multivariable analysis, a dose−response relationship was observed between the extent of ICAS versus WMH s. Compared with one ICAS lesion, for d‐ WMH s the odds ratio ( OR ) = 2.61 [95% confidence interval ( CI ) 0.95–7.20] for two ICAS lesions and OR  = 3.37 (1.10–10.32) for ≥3 ICAS lesions; whilst for p‐ WMH s (score ≥2) OR  = 1.70 (95% CI 0.96–2.98) for two ICAS lesions and OR  = 2.02 (1.15–3.55) for ≥3 ICAS lesions. Conclusion ICAS is independently associated with progressively greater WMH burden. The association of ICAS with WMH severity appears to be stronger than that of ECAS / NCAS in the Korean (Asian) stroke population.