Abstract WP121: Brain Structures Anormalites Detected By Voxel Based Morphometry In Individuals With Asymptomatic Carotid Stenosis

Background: Studies of patients with asymptomatic carotid stenosis have shown significant cognitive decline in this individuals compared to groups without stenosis. Our study aims to investigate the occurrence of subtle gray and white matter decrease in patients with asymptomatic carotid stenosis through Voxel Based Morphometry (VBM) analysis. Methods: Twenty-seven patients (7 women, mean age of 71 years, range 51- 78 years) with unilateral asymptomatic carotid stenosis (>70%) or occlusion, defined by angiotomography (CTA), were submitted to MRI and images were analyzed with VBM. MR images were acquired on a 3T-MR scanner, with sequence 3D sagittal T1-weighted (voxel size 1x1x1 mm,TR = 22 ms, TE = 9 ms, flip angle = 35°, matrix = 256x220). Images of patients with left carotid stenosis were flipped in the right-left orientation thus all hemispheres ipsilateral to the stenosis were aligned. For statistical comparisons, we used images of 27 healthy control subjects matched for sex and age with patient group (7 women, mean age of 68 years, range 54-82). VBM analysis was performed with VBM8/SPM8 toolbox (two-sample T-Test, P Results: VBM analysis demonstrated significant and diffuse gray matter reduction in both hemispheres of patient group. However, these abnormalities were more pronounced in the area correspondent to the anterior circulation of the hemisphere ipsilateral to the carotid stenosis. In contrast, white matter abnormalities detected by VBM were less evident and with symmetrical distribution in both hemispheres. Conclusion: Our findings suggest that asymptomatic carotid stenosis/occlusion is associated with subtle gray matter reduction predominantly in the ipsilateral hemisphere. This is in accordance with previous data demonstrating cognitive decline in these patients and it may imply that there is significant hemodynamic disturbance secondary to these stenosis.