Hippocampal volume in different neuropsychiatric cohorts using a semiautomatic a semiautomatic, stereological and automatic method
Year: 2011
Type: dissertation
Study design: Observational Study
Abstract: Introduction: In the recent literature on the course of different neuropsychiatric disorders, volumetric changes in the hippocampus, a limbic structure with anterior-posterior anatomical and functional segmentation, have been reported. We examined hippocampal volumes in subjects with Cushing’s disease (CD), in female patients with recurrent Familial Pure Depressive Disease (rFPDD) and in a population with mild Traumatic Brain Injury (mTBI), with the hypothesis that cortisol damage on the hippocampus (HC) has an anterior-posterior gradient , depending on the clinical situation and on the interaction between environment and genetic. Additionally, we decided to validate FreeSurfer, an automated software program developed at the Martinos Center for Biomedical Imaging (Harvard University, Boston, USA). This aim is in line with the current research for determining the volume of brain areas, which has been geared towards the development of automated methods of volumetric analysis that are highly reproducible, accurate and potentially more efficient than the current gold standard of the manual technique. I Methods: We used a semi-automated software program (DCM view, Padova Ricerche, Padova, Italy) for Magnetic Resonance Imaging (MRI) to measure hippocampal volumes in ten patients with CD prior to selective surgical resection of the adrenocorticotropic hormone (ACTH)-secreting pituitary micro-adenomas using a trans-sphenoidal approach and after an interval of one year following surgery. This same program was used to measure hippocampal volumes in 15 female patients with familial recurrent Major Depression (MD) and 15 healthy female subjects. We also examined hippocampal volumes using a stereological method, using Analyze software (version 10., Biomedical Imaging Resource, Mayo Foundation, Rochester, MN, USA), in a sample of subjects with mTBI within a month and a year after head injury. In the validation study, the hippocampal volumes of a sample of elderly subjects with unipolar major depression and healthy controls were estimated using a automated method. Using FreeSurfer software, a stereological method (manual) was then used to validate it. Moreover, the accuracy and precision of the automatic delineation of all images acquired were verified. Using ANCOVA with whole-brain volume and age as covariates, volumetric measurements in the two groups with the different disorders were compared. The agreement between the volumetric measures within and between the two methods was determined by calculating Cronbach's alpha coefficient for intra- and inter-rater reliability tests. Results: We found a significant difference in the head of the hippocampus bilaterally 12 months after selective trans-sphenoidal surgical resection of the adrenocorticotropic hormone (ACTH)-secreting pituitary micro-adenomas. The right hippocampal body and tail volumes were significantly smaller in female patients with familial depressive disorder when compared to healthy subjects. No significant differences in hippocampal volumes were found in subjects with mTBI. The test of agreement between the volumetric methods was good, whereas the verification analysis for the quality of the tracing using FreeSurfer was not found to be favourable for segmentation of the hippocampus. Conclusions: The pre-post surgery difference found in our CD patients could contribute to increased the understanding of the pathophysiology of CD as an in vivo model for stress-related hypercortisolemic neuropsychiatric disorders. Our data provide evidence for structural lateralised hippocampal body and tail abnormalities in women with a familial history and recurrent episodes of depression. Although global reductions in hippocampal volume have already been widely reported, data on lateralised regional reductions in samples with familial recurrent depression had not been previously reported. Reductions in right posterior hippocampal volume may be a structural endophenotype for recurrent depressive disorders in women. A bigger sample of subjects and functional neuroimaging studies are necessary to form conclusions concerning changes in the brain structures of subjects with mTBI. The validation data from this study indicate that the automated method should be improved.
Author: Tommaso Toffanin
Language: English
Subfield: Behavioral Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2286056101