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Published on: January 2, 2012
Cortical thickness reduction of normal appearing cortex in patients with polymicrogyria
Pedro Paulo de Magalhães Oliveira1, Kette Dualibi Valente, Sukhwinder S Shergill
1Neuroimagem Funcional (NIF), Departamento de Radiologia da Faculdade de Medicina do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil. ppj@netfilter.com.br
Objective:
To examine cortical thickness and volumetric changes in the cortex of patients with polymicrogyria, using an automated image analysis algorithm.
Methods:
Cortical thickness of patients with polymicrogyria was measured using magnetic resonance imaging (MRI) cortical surface-based analysis and compared with age- and sex-matched healthy subjects. We studied 3 patients with disorder of cortical development (DCD), classified as polymicrogyria, and 15 controls. Two experienced neuroradiologists performed a conventional visual assessment of the MRIs. The same data were analyzed using an automated algorithm for tissue segmentation and classification. Group and individual average maps of cortical thickness differences were produced by cortical surface-based statistical analysis.
Results:
Patients with polymicrogyria showed increased thickness of the cortex in the same areas identified as abnormal by radiologists. We also identified a reduction in the volume and thickness of cortex within additional areas of apparently normal cortex relative to controls.
Conclusions:
Our findings indicate that there may be regions of reduced cortical thickness, which appear normal from radiological analysis, in the cortex of patients with polymicrogyria. This finding suggests that alterations in neuronal migration may have an impact in the cortical formation of the cortical areas that are visually normal. These areas are associated or occur concurrently with polymicrogyria.
