Cerebral white matter lesions in patients with dementia - from MCI to severe Alzheimer's disease.

BACKGROUND

Brain images of patients with Alzheimer's disease (AD) on magnetic resonance imaging (MRI) show white matter lesions (WML), which are attributed to degenerative changes of small vessels. These lesions are supposed to be among the factors supporting the diagnosis of probable AD; however their correlation with the severity of dementia requires further studies.

METHODS

We examined four groups of patients with cognitive impairment: Ten patients with amnestic-MCI (Mild Cognitive Impairment), 11 with mild AD (21-24 points in MMSE), 17 with moderate AD (11-20 points in MMSE) and 15 with severe AD (3-10 points in MMSE). The T2 and FLAIR MRI sequences of the brain of each patient were assessed using the White Matter Lesions Semiquantitive Rating Scale, taking into consideration the amount, size and distribution of WML.

RESULTS

WML of the brain were seen in almost all patients with AD and MCI on T2 and FLAIR sequences. The positive correlation between the patients' age and the amount and size of WML, in subcortical (T2: p<0.01, r=0.39; FLAIR: p<0.05, r=0.31) and in the periventricular region (T2: p<0.05, r=0.28; FLAIR: p<0.05, r=0.35) has been shown on both sequences. There was no correlation between the size or distribution of lesions and either hypertension or homocysteine blood level. The analysis revealed also that in both sequences, the severity of lesions in the periventricular region increased with the progression of the disease (T2: p=0.038; FLAIR: p=0.02).

CONCLUSIONS

A significant factor correlating with the location of WML in patients with MCI and AD is the age of patient. The amount and size of WML in the periventricular and subcortical regions of the brain correlates with the severity of dementia. Hypertension and hyperhomocysteinemia have no influence on the presence of described lesions.