Cerebral vasomotor reactivity and cerebral white matter lesions in the elderly

Objective: The pathogenesis of white matter lesions is still uncertain, but an ischemic-hypoxic cause has been suggested. Cerebral vasomotor reactivit y reflects the compensatory dilatory mechanism of the intracerebral arterio les to a vasodilatory stimulus and provides a more sensitive hemodynamic in dex than the level of resting now. Methods: The authors determined the asso ciation between vasomotor reactivity and white matter lesions in 73 consecu tive individuals from the Rotterdam Scan Study who also participated in the Rotterdam Study, a large population-based prospective follow-up study of i ndividuals greater than or equal to 55 years old. Vasomotor reactivity was measured by means of CO2-enhanced transcranial Doppler, and in all individu als axial T1*-, T2*'-, and proton density (PD)-weighted MRI scans (1.5 T) w ere obtained. White matter lesions were scored according to location, size, and number by two independent readers. Results: Vasomotor reactivity was i nversely associated with the deep subcortical and total periventricular whi te matter lesions (OR 0.5, 95% CI 0.3 to 1.1; and OR 0.7, 95% CI 0.4 to 1.1 , respectively). A strong association was found between impaired vasomotor reactivity and periventricular white matter lesions adjacent to the lateral ventricular wall (OR 0.6, 95% CI 0.4 to 1.0; p = 0.001). No association wa s found with periventricular white matter lesions near the frontal and occi pital horns. Conclusions: Our data confirm the association between vasomoto r reactivity and white matter lesions and support the hypothesis that some white matter lesions may be associated with hemodynamic ischemic injury to the brain.