Prevalence of and Factors Associated with Dural Thickness in Patients with Mild Cognitive Impairment and Alzheimer's Disease.

BACKGROUND AND PURPOSE We performed this study to evaluate the prevalence of and factors associated with dural thickening in patients with mild cognitive impairment and Alzheimer's disease. METHODS Alzheimer's disease neuroimaging initiative participants with axial FLAIR sequence magnetic resonance imaging (MRI) images were analyzed. Dural thickness was defined by a linear strip of hyperintense tissue signal along the dura mater observed in at least two different images without evidence of leptomeningeal involvement. RESULTS Dural thickening was seen in 83 (34%) of 242 persons analyzed (mean age [±SD] 74±7 years: 150 were men) with either mild cognitive impairment or Alzheimer's disease. The mini mental score was not different in persons with (26±0.3) and without (26±0.2) dural thickening (p = 0.6). The proportion of patients with moderate or severe cognitive impairment (defined by mini mental status score) was similar at baseline and at 12-month evaluations. The rates of annual progression according to Alzheimer's disease assessment scale (p = 0.06) and clinical dementia scale (p = 0.001) were higher in persons without dural thickening. The annual rate of volume loss in entorhinal cortex was higher among persons with dural thickening. CONCLUSIONS We found relatively high prevalence of dural thickening in patients with mild cognitive impairment and Alzheimer's disease.