Biomedical subjects

Hyun-Pil Kim

Publications and source records attributed to Hyun-Pil Kim.

3 recordsLinked to original sources

PubMed2006

An MRI study of structural variations in schizophrenia using deformation field morphometry.

Magnetic resonance imaging (MRI) has an important role in investigating the changes in brain structure that are associated with schizophrenia. In this study, MRI scans of patients diagnosed with schizophrenia (37 males; 19 females; 17-42 years of age) were compared with those of an age- and sex-matched group of normal subjects (37 males; 19 females; 18-40 years of age). Based on the images of the healthy control subjects, we constructed a representative average brain template. Automated image analysis techniques were used to measure differences in the regional nonlinear deformation fields between the two groups. A deformation field, which measures the spatial transformation to deform a template of brain anatomy to each individual data, was obtained as a three-dimensional displacement vector in each voxel. There was a significantly greater magnitude of the deformation fields in the superior frontal and parietal lobes as well as in the cingulate gyrus connecting both lobes of the patients with schizophrenia than in those of healthy controls, suggesting that these cerebral regions have a significantly higher structural variability in schizophrenia.

Adolescent↗

PubMed2005

Representative brain selection using a group-specific tissue probability map.

PURPOSE: To determine the anatomy of a standard brain reflecting well-defined group characteristics based on probabilistic information from group-specific anatomical variations. MATERIALS AND METHODS: We constructed a group-specific tissue probabilistic map for 20 subjects and used it to extract voxel-wise probabilistic information for each subject through regional spatial normalization using Automated Image Registration software (AIR 5.2.5). Extracted probabilistic information was then used to determine standard properties of the subjects. For comparison, we employed an empirical scoring function - a measure of entropy - in ordering the data set. A brain with minimum entropy was then selected for a group standard. The evaluation of our proposed method was performed using two different selection schemes: deformation analysis and similarity index measurements. RESULTS: This method showed highly correlated result with previous method by Kochunov et al., with fewer computational tasks. CONCLUSION: This method can thus be used to determine an appropriate standard model to compare with disease-affected brains.

Adult↗

PubMed2005

Asymmetry analysis of deformable hippocampal model using the principal component in schizophrenia.

The hippocampus is thought to play an important role in learning and memory processing, and impairments in memory, attention, and decision making are found commonly in schizophrenia. Although many studies have reported decreases in hippocampal volume in the left hemisphere in schizophrenia, regionally specific hippocampal volume loss has not been revealed consistently using volume analysis. Recently, many studies have analyzed shape asymmetry using 3-D models; however, inconsistent results have been reported, mainly due to methodologic differences. We therefore used an active, flexible, deformable shape model for surface parameterization, and compared shape asymmetry based on principal component analysis (PCA) in the hippocampi of schizophrenic patients with those of the normal controls. Although the overall pattern of the statistical results did not change according to the number of principal components, the reconstructed results based on six major components were much more distinguishable. Although the left hemispheric hippocampal volume was larger than the right hemispheric was in this study, the difference was not significant. In shape asymmetry analysis, the right hemisphere hippocampus was bilaterally larger than the left hemisphere hippocampus was in the head of the superior CA1 and smaller in the tail and head of the inferior CA1. The asymmetry in the schizophrenia group was statistically smaller than that in the control group through reduction of the left hemisphere hippocampus volume.

Adult↗