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1.
Heliyon ; 8(12): e12066, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36544835

ABSTRACT

As the performance requirement for the X-band radar for military use increased, the X-band radar has come to consist of many Transmit/Receive (T/R) modules. So then, the importance of the cooling system is increasing significantly to ensure the operations of the radar during military action. However, satisfying the required cooling performance with the simple square cooling channel is difficult. This study proposes a two-layer cooling channel with the impinging jet array in the T/R modules to overcome the limitation of the existing cooling channel. This two-layer cooling channel was designed to discharge the cooling flow after cooling the individual T/R module to maximize the cooling performance. The cooling performance was evaluated under various mass flow conditions through Ansys Fluent v19.5. The boundary conditions were based on the actual T/R module, and the cooling performance was calculated by pressure drop and convective heat transfer coefficient on the cooling channel. The cooling performance of the two-layer cooling channel was higher than that of the square cooling channel. In particular, the cooling performance was improved up to 4.5 times under low mass flow conditions. The cooling performance was improved by improving convective heat transfer and by increasing the heat transfer area. It is expected that the detection range and resolution can be enhanced when the two-layer cooling channel is applied to X-band radar in the future.

2.
PLoS One ; 17(3): e0265671, 2022.
Article in English | MEDLINE | ID: mdl-35303011

ABSTRACT

This study aimed to investigate alterations in white matter (WM) microstructure in patients with psychotic and non-psychotic bipolar disorder (PBD and NPBD, respectively). We used 3T-magnetic resonance imaging to examine 29 PBD, 23 NPBD, and 65 healthy control (HC) subjects. Using tract-based spatial statistics for diffusion tensor imaging data, we compared fractional anisotropy (FA) and mean diffusion (MD) pairwise among the PBD, NPBD, and HC groups. We found several WM areas of decreased FA or increased MD in the PBD and NPBD groups compared to HC. PBD showed widespread FA decreases in the corpus callosum as well as the bilateral internal capsule and fornix. However, NPBD showed local FA decreases in a part of the corpus callosum body as well as in limited regions within the left cerebral hemisphere, including the anterior and posterior corona radiata and the cingulum. In addition, both PBD and NPBD shared widespread MD increases across the posterior corona radiata, cingulum, and sagittal stratum. These findings suggest that widespread WM microstructural alterations might be a common neuroanatomical characteristic of bipolar disorder, regardless of being psychotic or non-psychotic. Particularly, PBD might involve extensive inter-and intra-hemispheric WM connectivity disruptions.


Subject(s)
Bipolar Disorder , White Matter , Anisotropy , Bipolar Disorder/diagnostic imaging , Bipolar Disorder/pathology , Brain/diagnostic imaging , Brain/pathology , Diffusion Tensor Imaging/methods , Humans , White Matter/diagnostic imaging , White Matter/pathology
3.
Exp Neurobiol ; 31(6): 401-408, 2022 Dec 31.
Article in English | MEDLINE | ID: mdl-36631848

ABSTRACT

Striatal changes in the pathogenesis of Alzheimer's disease (AD) is not fully understood yet. We compared structural and functional image differences in the striatum between patients with early onset AD (EOAD) and late onset AD (LOAD) to investigate whether EOAD harbors autosomal dominant AD like imaging findings. The clinical, neuropsychological and neuroimaging biomarkers of 77 probable AD patients and 107 elderly subjects with normal cognition (NC) from the Alzheimer's Disease Neuroimaging Initiative (ADNI)-2 dataset were analyzed. Enrolled each subject completed a 3-Tesla MRI, baseline 18F-FDG-PET, and baseline 18F-AV-45 (Florbetapir) amyloid PET studies. AD patients were divided into two groups based on the onset age of clinical symptoms (EOAD <65 yrs; LOAD ≥65 yrs). A standardized uptake value ratio of the striatum and subcortical structures was obtained from both amyloid and FDG-PET scans. Structural MR imaging analysis was conducted using a parametric boundary description protocol, SPHARM-PDM. Of the 77 AD patients, 18 were EOAD and 59 were LOAD. Except for age of symptom onset, there were no statistically significant differences between the groups in demographics and detailed neuropsychological test results. 18F-AV-45 amyloid PET showed marked ß-amyloid accumulation in the bilateral caudate nucleus and left pallidum in the EOAD group. Intriguingly, the caudate nucleus and putamen showed maintained glucose metabolism in the EOAD group compared to the LOAD group. Our image findings in the striatum of EOAD patients suggest that sporadic EOAD may share some pathophysiological changes noted in autosomal dominant AD.

4.
Clin Psychopharmacol Neurosci ; 18(4): 571-579, 2020 Nov 30.
Article in English | MEDLINE | ID: mdl-33124589

ABSTRACT

OBJECTIVE: : This study used network analyses to examine network structures reflecting interactions between specific domains of social functioning in schizophrenia (SZ) and bipolar disorder (BD). METHODS: We used the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) to assess six domains of social functioning ('cognition', 'mobility', 'self-care', 'getting along', 'life activities', and 'participation') in 143 patients with SZ, 81 patients with BD, and 106 healthy subjects. We constructed regularized partial correlation networks, estimated network centrality and edge strength, tested network stability, and compared SZ and BD network structures. RESULTS: Patients with SZ showed a significantly higher level of functional disability than patients with BD. In the networks we constructed, 'cognition' was the most central domain of social functioning in both SZ and BD. The 'cognition' domain was primarily associated with the 'getting along' domain in the SZ network and the 'life activities' domain in the BD network. We found no significant group-level differences in network structures for SZ vs. BD. CONCLUSION: Our results suggest that cognition may play a pivotal role in social functioning in both SZ and BD. In addition, domains of social functioning in SZ and BD have similar network structures despite the higher level of disability in SZ compared to BD.

5.
J Clin Med ; 9(8)2020 Aug 17.
Article in English | MEDLINE | ID: mdl-32824599

ABSTRACT

White matter hyperintensity (WMH) has been recognised as a surrogate marker of small vessel disease and is associated with cognitive impairment. We investigated the dynamic change in WMH in patients with severe WMH at baseline, and the effects of longitudinal change of WMH volume on cognitive decline and cortical thinning. Eighty-seven patients with subcortical vascular mild cognitive impairment were prospectively recruited from a single referral centre. All of the patients were followed up with annual neuropsychological tests and 3T brain magnetic resonance imaging. The WMH volume was quantified using an automated method and the cortical thickness was measured using surface-based methods. Participants were classified into WMH progression and WMH regression groups based on the delta WMH volume between the baseline and the last follow-up. To investigate the effects of longitudinal change in WMH volume on cognitive decline and cortical thinning, a linear mixed effects model was used. Seventy patients showed WMH progression and 17 showed WMH regression over a three-year period. The WMH progression group showed more rapid cortical thinning in widespread regions compared with the WMH regression group. However, the rate of cognitive decline in language, visuospatial function, memory and executive function, and general cognitive function was not different between the two groups. The results of this study indicated that WMH volume changes are dynamic and WMH progression is associated with more rapid cortical thinning.

6.
Psychiatry Investig ; 17(7): 627-635, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32571005

ABSTRACT

OBJECTIVE: More recently, attention has turned to the linkage between childhood trauma and emotional dysregulation, but the evidence in bipolar disorder (BD) is limited. To determine neurobiological relationships between childhood trauma, current anxiety, and impulsivity, we investigated cortical volumetric correlates of these clinical factors in BD. METHODS: We studied 36 patients with DSM-5 BD and 29 healthy controls. Childhood trauma, coexisting anxiety, and impulsivity were evaluated with the Korean version-Childhood Trauma Questionnaire (CTQ), the Korean version-Beck Anxiety Inventory (BAI), and the Korean version-Barratt Impulsiveness Scale (BIS). Voxel-based morphometry (VBM) was used to assess gray matter volume (GMV) alterations on the brain magnetic resonance imaging (MRI). Partial correlation analyses were conducted to examine associations between the GMV and each scale in the BD group. RESULTS: Childhood trauma, anxiety, and impulsivity were interrelated in BD. BD patients revealed significant inverse correlations between the GMV in the right precentral gyrus and CTQ scores (r=-0.609, p<0.0003); between the GMV in the left middle frontal gyrus and BAI scores (r=-0.363, p=0.044). Moreover, patients showed similar tendency of negative correlations between the GMV in the right precentral gyrus and BIS scores; between the GMV in the left middle frontal gyrus and CTQ scores. CONCLUSION: The present study provides evidence for a neural basis between childhood trauma and affect regulations in BD. The GMV alterations in multiple frontal lobe areas may represent neurobiological markers for anticipating the course of BD.

7.
PLoS One ; 15(5): e0232826, 2020.
Article in English | MEDLINE | ID: mdl-32379845

ABSTRACT

This study aimed to investigate abnormalities in the gray matter and white matter (GM and WM, respectively) that are shared between schizophrenia (SZ) and bipolar disorder (BD). We used 3T-magnetic resonance imaging to examine patients with SZ, BD, or healthy control (HC) subjects (aged 20-50 years, N = 65 in each group). We generated modulated GM maps through voxel-based morphometry (VBM) for T1-weighted images and skeletonized fractional anisotropy, mean diffusion, and radial diffusivity maps through tract-based special statistics (TBSS) methods for diffusion tensor imaging (DTI) data. These data were analyzed using a generalized linear model with pairwise comparisons between groups with a family-wise error corrected P < 0.017. The VBM analysis revealed widespread decreases in GM volume in SZ compared to HC, but patients with BD showed GM volume deficits limited to the right thalamus and left insular lobe. The TBSS analysis showed alterations of DTI parameters in widespread WM tracts both in SZ and BD patients compared to HC. The two disorders had WM alterations in the corpus callosum, superior longitudinal fasciculus, internal capsule, external capsule, posterior thalamic radiation, and fornix. However, we observed no differences in GM volume or WM integrity between SZ and BD. The study results suggest that GM volume deficits in the thalamus and insular lobe along with widespread disruptions of WM integrity might be the common neural mechanisms underlying the pathologies of SZ and BD.


Subject(s)
Bipolar Disorder/pathology , Gray Matter/pathology , Schizophrenia/pathology , White Matter/pathology , Adult , Female , Humans , Male , Middle Aged , Young Adult
8.
Psychiatry Investig ; 16(8): 588-593, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31446686

ABSTRACT

OBJECTIVE: We aimed to develop predictive models to identify suicide attempters among individuals with suicide ideation using a machine learning algorithm. METHODS: Among 35,116 individuals aged over 19 years from the Korea National Health & Nutrition Examination Survey, we selected 5,773 subjects who reported experiencing suicide ideation and had answered a survey question about suicide attempts. Then, we performed resampling with the Synthetic Minority Over-sampling TEchnique (SMOTE) to obtain data corresponding to 1,324 suicide attempters and 1,330 non-suicide attempters. We randomly assigned the samples to a training set (n=1,858) and a test set (n=796). In the training set, random forest models were trained with features selected through recursive feature elimination with 10-fold cross validation. Subsequently, the fitted model was used to predict suicide attempters in the test set. RESULTS: In the test set, the prediction model achieved very good performance [area under receiver operating characteristic curve (AUC)=0.947] with an accuracy of 88.9%. CONCLUSION: Our results suggest that a machine learning approach can enable the prediction of individuals at high risk of suicide through the integrated analysis of various suicide risk factors.

9.
Neuroimage Clin ; 22: 101805, 2019.
Article in English | MEDLINE | ID: mdl-30991621

ABSTRACT

This study investigated whether resting-state functional connectivity is associated with long-term clinical outcomes of patients with schizophrenia. Resting-state brain images were obtained from 79 outpatients with schizophrenia and 30 healthy controls (HC), using a 3 T-MRI scanner. All patients were 20-50 years old with >3 years' duration of illness and appeared clinically stable. We assessed their psychopathology using the 18-item Brief Psychiatric Rating Scale (BPRS-18) and divided them into "good," "moderate," and "poor" outcome (SZ-GO, SZ-MO, and SZ-PO) groups depending on BPRS-18 total score. We obtained individual functional connectivity maps between a seed region of the bilateral posterior cingulate cortex (PCC) and all other brain regions and compared the functional connectivity of the default mode network (DMN) among the HC and 3 schizophrenia outcome groups, with a voxel-wise threshold of P < .001 within a cluster-extent threshold of 114 voxels. Additionally, we assessed correlations between functional connectivity and BPRS-18 scores. The SZ-MO and SZ-PO groups showed decreased functional connectivity between PCC and right ventromedial prefrontal cortex (vmPFC), left middle cingulate cortex, and left frontopolar cortex (FPC) compared to the SZ-GO and HC groups. DMN connectivity in the right vmPFC and left FPC negatively correlated with subscale scores of the BPRS-18, except the negative symptoms subscale. In this study, poorer clinical outcomes in patients with schizophrenia were associated with decreased DMN connectivity. In particular, the decreased functional connectivity might be related to the severity of positive and mood symptoms rather than negative symptoms.


Subject(s)
Connectome , Nerve Net/physiopathology , Outcome Assessment, Health Care , Prefrontal Cortex/physiopathology , Schizophrenia/physiopathology , Severity of Illness Index , Adult , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Nerve Net/diagnostic imaging , Prefrontal Cortex/diagnostic imaging , Schizophrenia/diagnostic imaging
10.
Psychiatry Investig ; 15(11): 1030-1036, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30301301

ABSTRACT

OBJECTIVE: In this study, we aimed to develop a model predicting individuals with suicide ideation within a general population using a machine learning algorithm. METHODS: Among 35,116 individuals aged over 19 years from the Korea National Health & Nutrition Examination Survey, we selected 11,628 individuals via random down-sampling. This included 5,814 suicide ideators and the same number of non-suicide ideators. We randomly assigned the subjects to a training set (n=10,466) and a test set (n=1,162). In the training set, a random forest model was trained with 15 features selected with recursive feature elimination via 10-fold cross validation. Subsequently, the fitted model was used to predict suicide ideators in the test set and among the total of 35,116 subjects. All analyses were conducted in R. RESULTS: The prediction model achieved a good performance [area under receiver operating characteristic curve (AUC)=0.85] in the test set and predicted suicide ideators among the total samples with an accuracy of 0.821, sensitivity of 0.836, and specificity of 0.807. CONCLUSION: This study shows the possibility that a machine learning approach can enable screening for suicide risk in the general population. Further work is warranted to increase the accuracy of prediction.

11.
Genomics Inform ; 14(1): 20-8, 2016 Mar.
Article in English | MEDLINE | ID: mdl-27103887

ABSTRACT

Internet addiction (IA) has become a widespread and problematic phenomenon as smart devices pervade society. Moreover, internet gaming disorder leads to increases in social expenditures for both individuals and nations alike. Although the prevention and treatment of IA are getting more important, the diagnosis of IA remains problematic. Understanding the neurobiological mechanism of behavioral addictions is essential for the development of specific and effective treatments. Although there are many databases related to other addictions, a database for IA has not been developed yet. In addition, bioinformatics databases, especially genetic databases, require a high level of security and should be designed based on medical information standards. In this respect, our study proposes the OAuth standard protocol for database access authorization. The proposed IA Bioinformatics (IABio) database system is based on internet user authentication, which is a guideline for medical information standards, and uses OAuth 2.0 for access control technology. This study designed and developed the system requirements and configuration. The OAuth 2.0 protocol is expected to establish the security of personal medical information and be applied to genomic research on IA.

12.
Mult Scler ; 22(14): 1850-1858, 2016 12.
Article in English | MEDLINE | ID: mdl-26920380

ABSTRACT

OBJECTIVE: To compare the frequency and pattern of cognitive impairment (CI) between patients with neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS). METHODS: A total of 82 NMOSD patients, 58 MS patients, and 45 healthy controls (HCs) underwent a neuropsychological assessment. RESULTS: CI was observed in 29% of NMOSD and 50% of MS patients (p < 0.001); CI was considered present if a patient scored lower than the fifth percentile compared with HCs in at least three domains. A lower frequency of CI was consistently found when CI was indicated by at least two failed tests (p < 0.001). MS patients performed worse than did NMOSD patients on verbal learning and verbal and visual memory tests. Levels of education and depression and the interval from disease onset to treatment were associated with a negative influence on cognition in patients with NMOSD. CONCLUSION: CI in patients with NMOSD may be not as common as in patients with MS. MS patients exhibited severe impairment, particularly on learning and memory tests, compared with NMOSD patients. Differential prevalence and patterns of CI between NMOSD and MS patients suggest that the two diseases have different mechanisms of brain injury.


Subject(s)
Cognitive Dysfunction/physiopathology , Multiple Sclerosis/physiopathology , Neuromyelitis Optica/physiopathology , Adult , Cognitive Dysfunction/diagnostic imaging , Cognitive Dysfunction/epidemiology , Cognitive Dysfunction/etiology , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Multiple Sclerosis/complications , Multiple Sclerosis/diagnostic imaging , Multiple Sclerosis/epidemiology , Neuromyelitis Optica/complications , Neuromyelitis Optica/diagnostic imaging , Neuromyelitis Optica/epidemiology
13.
Brain Imaging Behav ; 10(4): 1015-1028, 2016 12.
Article in English | MEDLINE | ID: mdl-26497891

ABSTRACT

Our goal was to investigate whether three-dimensional (3D) double inversion recovery (DIR) images can show alterations of gray matter volume (GMV) between Alzheimer's disease (AD) patients and nondemented controls and to compare alterations of GMV between groups using DIR images and those using 3D T1-weighted (T1W) images. We included 25 subjects with mild or probable AD, 25 subjects with amnestic mild cognitive impairment (MCI), and 25 elderly cognitively normal (CN) subjects. Group differences in GMV among CN, MCI, and AD patients were tested by voxel-wise, one-way ANOVA. Additional region-of-interest-based comparisons of GMV differences among the three groups for DIR and T1WI were performed using ANCOVA. Finally, ROC curve analysis was performed. In the AD group compared with the CN and MCI groups, GMV was decreased in both DIR and T1W images. However, the areas showing GMV loss were larger in DIR images compared to those in T1W images. Amygdala had the highest area under curve value for both DIR and T1W images. DIR images were sensitive for identifying GMV loss in patients with AD compared with MCI and CN subjects and areas showing GMV loss identified with DIR were extended to more brain areas than those identified with T1W. With DIR, amygdala GMV is the most sensitive in differentiating between subject groups.


Subject(s)
Alzheimer Disease/diagnostic imaging , Cognitive Dysfunction/diagnostic imaging , Gray Matter/diagnostic imaging , Magnetic Resonance Imaging/methods , Aged , Analysis of Variance , Area Under Curve , Computer Simulation , Diagnosis, Differential , Female , Humans , Image Processing, Computer-Assisted , Male , Mental Status Schedule , Models, Neurological , Neuropsychological Tests , Organ Size , Prospective Studies , ROC Curve
14.
Cerebellum ; 15(2): 174-81, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26062905

ABSTRACT

Postmortem studies of essential tremor (ET) have demonstrated the presence of degenerative changes in the cerebellum, and imaging studies have examined related structural changes in the brain. However, their results have not been completely consistent and the number of imaging studies has been limited. We aimed to study cerebellar involvement in ET using MRI segmental volumetric analysis. In addition, a unique feature of this study was that we stratified ET patients into subtypes based on the clinical presence of cerebellar signs and compared their MRI findings. Thirty-nine ET patients and 36 normal healthy controls, matched for age and sex, were enrolled. Cerebellar signs in ET patients were assessed using the clinical tremor rating scale and International Cooperative Ataxia Rating Scale. ET patients were divided into two groups: patients with cerebellar signs (cerebellar-ET) and those without (classic-ET). MRI volumetry was performed using CIVET pipeline software. Data on whole and segmented cerebellar volumes were analyzed using SPSS. While there was a trend for whole cerebellar volume to decrease from controls to classic-ET to cerebellar-ET, this trend was not significant. The volume of several contiguous segments of the cerebellar vermis was reduced in ET patients versus controls. Furthermore, these vermis volumes were reduced in the cerebellar-ET group versus the classic-ET group. The volume of several adjacent segments of the cerebellar vermis was reduced in ET. This effect was more evident in ET patients with clinical signs of cerebellar dysfunction. The presence of tissue atrophy suggests that ET might be a neurodegenerative disease.


Subject(s)
Cerebellar Vermis/physiopathology , Essential Tremor/physiopathology , Adult , Aged , Aged, 80 and over , Atrophy/metabolism , Cerebellar Ataxia/physiopathology , Female , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged
15.
Neurodegener Dis ; 15(5): 294-300, 2015.
Article in English | MEDLINE | ID: mdl-26202063

ABSTRACT

BACKGROUND/AIMS: Previous studies indicate that patients with the parkinsonian subtype of multiple system atrophy (MSA-P) experience cognitive impairment. This study aimed to identify the existence of cognitive impairments and the different topographic patterns of morphological changes in MSA-P by means of imaging analysis, and also whether these morphological changes could be associated with cognitive dysfunctions in MSA-P. METHODS: We recruited 15 nondemented probable MSA-P patients and 32 normal controls (NC) for neuropsychological testing and MRI. We analyzed morphological changes using cortical thickness analysis, voxel-based morphometry (VBM) and cerebellar volumetry. Multiple linear regression analysis was performed to evaluate the correlation of each cognitive score with the mean thickness of significant cortical-thinning clusters, mean gray-matter density of VBM clusters and cerebellar volume. RESULTS: The scores on the Digit Span Test, the Seoul Verbal Learning Test (immediate and delayed), the phonemic Controlled Oral Word Association Test and the Stroop color test were significantly lower in the MSA-P group than in the NC group. We found two clusters exhibiting significant cortical thinning in the right paracentral lobule and parahippocampal gyrus. VBM analysis revealed significant gray-matter atrophy in the MSA-P group in the bilateral basal ganglia, cerebellum and temporal and frontal cortical areas. Multiple linear regression analysis demonstrated that cognitive dysfunction correlated significantly with thinning in the neocortex, cerebellum and striatum. CONCLUSIONS: Our data demonstrate that cortical and cerebellar atrophy and striatal degeneration are associated with cognitive impairment in patients with MSA-P.


Subject(s)
Brain/pathology , Cognition Disorders/etiology , Multiple System Atrophy/pathology , Multiple System Atrophy/psychology , Parkinsonian Disorders/pathology , Parkinsonian Disorders/psychology , Aged , Female , Humans , Male , Middle Aged , Multiple System Atrophy/complications , Neuropsychological Tests , Parkinsonian Disorders/complications
16.
Comput Math Methods Med ; 2015: 167489, 2015.
Article in English | MEDLINE | ID: mdl-26060504

ABSTRACT

While segmentation of the cerebellum is an indispensable step in many studies, its contrast is not clear because of the adjacent cerebrospinal fluid, meninges, and cerebra peduncle. Thus, various cerebellar segmentation methods, such as a deformable model or a template-based algorithm might exhibit incorrect segmentation of the venous sinuses and the cerebellar peduncle. In this study, we propose a fully automated procedure combining cerebellar tissue classification, a template-based approach, and morphological operations sequentially. The cerebellar region was defined approximately by removing the cerebral region from the brain mask. Then, the noncerebellar region was trimmed using a morphological operator and the brain-stem atlas was aligned to the individual brain to define the brain-stem area. The proposed method was validated with the well-known FreeSurfer and ITK-SNAP packages using the dice similarity index and recall and precision scores. As a result, the proposed method was significantly better than the other methods for the dice similarity index (0.93, FreeSurfer: 0.92, ITK-SNAP: 0.87) and precision (0.95, FreeSurfer: 0.90, ITK-SNAP: 0.93). Therefore, it could be said that the proposed method yielded a robust and accurate segmentation result. Moreover, additional postprocessing with the brain-stem atlas could improve its result.


Subject(s)
Cerebellum/anatomy & histology , Image Interpretation, Computer-Assisted/methods , Adult , Algorithms , Brain/anatomy & histology , Brain/physiology , Brain Mapping , Cerebellum/physiology , Computational Biology , Databases, Factual/statistics & numerical data , Female , Humans , Magnetic Resonance Imaging/statistics & numerical data , Male , Models, Anatomic , Models, Neurological , Young Adult
17.
PLoS One ; 8(12): e84054, 2013.
Article in English | MEDLINE | ID: mdl-24358327

ABSTRACT

BACKGROUND: Recent studies have suggested that essential tremor (ET) is a more complex and heterogeneous clinical entity than initially thought. In the present study, we assessed the pattern of cortical thickness and diffusion tensor white matter (WM) changes in patients with ET according to the response to propranolol to explore the pathogenesis underlying the clinical heterogeneity of ET. METHODS: A total of 32 patients with drug naive ET were recruited prospectively from the Movement Disorders outpatient clinic. The patients were divided into a propranolol-responder group (n = 18) and a non-responder group (n = 14). We analyzed the pattern of cortical thickness and diffusion tensor WM changes between these two groups and performed correlation analysis between imaging and clinical parameters. RESULTS: There were no significant differences in demographic characteristics, general cognition, or results of detailed neuropsychological tests between the groups. The non-responder group showed more severe cortical atrophy in the left orbitofrontal cortex and right temporal cortex relative to responders. However, the responders exhibited significantly lower fractional anisotropy values in the bilateral frontal, corpus callosal, and right parietotemporal WM compared with the non-responder group. There were no significant clusters where the cortical thickness or WM alterations were significantly correlated with initial tremor severity or disease duration. CONCLUSIONS: The present data suggest that patients with ET have heterogeneous cortical thinning and WM alteration with respect to responsiveness to propranolol, suggesting that propranolol responsiveness may be a predictive factor to determine ET subtypes in terms of neuroanatomical heterogeneity.


Subject(s)
Cerebral Cortex/pathology , Diffusion Tensor Imaging , Essential Tremor/pathology , Essential Tremor/physiopathology , Adrenergic beta-Antagonists/therapeutic use , Aged , Anisotropy , Cerebral Cortex/drug effects , Essential Tremor/diagnosis , Essential Tremor/drug therapy , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Prognosis , Propranolol/therapeutic use , Treatment Outcome
18.
Parkinsonism Relat Disord ; 19(11): 970-4, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23867866

ABSTRACT

BACKGROUND AND PURPOSE: Despite the predominant degeneration of subcortical structures, recent studies have suggested the evidence of cortical involvement in multiple system atrophy (MSA). This study aimed to identify the different topographic pattern of cortical thinning in MSA according to clinical subtypes, and the association of cortical thinning with cerebellar atrophy and other disease related metrics. MATERIALS AND METHODS: We used cortical thickness analysis in 53 non-demented probable MSA patients (29 with MSA-C, 24 with MSA-P) and 35 healthy subjects and modeled local cortical thickness as a linear association with cerebellar volume and disease related metrics including age, disease duration, cognition and disease severity. RESULTS: We found five clusters (left ventromedial prefrontal, bilateral ventrolateral prefrontal cortex, right parahippocampal and lingual gyrus) exhibiting significant cortical thinning in MSA-C and two clusters (right primary sensory motor and left ventromedial prefrontal cortex) exhibiting a thinning tendency in MSA-P compared with the control group. In correlation analysis, we identified no cluster exhibiting a significant correlation with cerebellar atrophy in both of the MSA groups. However, cortical thickness in right parahippocampalgyrus and left ventrolateral prefrontal cortex showed significant negative correlation with International Cooperative Ataxia Rating Scale subscore of speech disorder in MSA-C group. CONCLUSIONS: We identified different topographic distributions of cortical thinning in MSA subtypes. Our study suggests that cortical thinning of MSA occurs independently of cerebellar atrophy as a primary disease process rather than secondary deafferentation.


Subject(s)
Brain Mapping/methods , Cerebral Cortex/pathology , Multiple System Atrophy/classification , Multiple System Atrophy/diagnosis , Aged , Female , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged
19.
Magn Reson Imaging ; 31(7): 1190-6, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23684964

ABSTRACT

The hippocampus has been known to be an important structure as a biomarker for Alzheimer's disease (AD) and other neurological and psychiatric diseases. However, it requires accurate, robust and reproducible delineation of hippocampal structures. In this study, an automated hippocampal segmentation method based on a graph-cuts algorithm combined with atlas-based segmentation and morphological opening was proposed. First of all, the atlas-based segmentation was applied to define initial hippocampal region for a priori information on graph-cuts. The definition of initial seeds was further elaborated by incorporating estimation of partial volume probabilities at each voxel. Finally, morphological opening was applied to reduce false positive of the result processed by graph-cuts. In the experiments with twenty-seven healthy normal subjects, the proposed method showed more reliable results (similarity index=0.81±0.03) than the conventional atlas-based segmentation method (0.72±0.04). Also as for segmentation accuracy which is measured in terms of the ratios of false positive and false negative, the proposed method (precision=0.76±0.04, recall=0.86±0.05) produced lower ratios than the conventional methods (0.73±0.05, 0.72±0.06) demonstrating its plausibility for accurate, robust and reliable segmentation of hippocampus.


Subject(s)
Alzheimer Disease/pathology , Brain Mapping/methods , Hippocampus/pathology , Aged , Algorithms , Automation , False Positive Reactions , Humans , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Middle Aged , Pattern Recognition, Automated/methods , Probability , Reproducibility of Results
20.
Arch Otolaryngol Head Neck Surg ; 136(6): 610-5, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20566913

ABSTRACT

OBJECTIVES: To compare the volume of the maxillary sinus, dental factors, and craniofacial anatomical features between control subjects and patients with chronic rhinosinusitis (CRS) and to investigate critical factors for the volumetric change in the maxillary sinus in adults. DESIGN: Retrospective case-control study. SETTING: Tertiary referral center. PARTICIPANTS: Ninety-nine individuals who visited an allergy and sinus center: 52 control subjects (septal deviation; mean age, 32.69 years) and 47 patients with CRS (mean age, 44.43 years). INTERVENTION: Cephalometry and computed tomography were performed in all the participants. In blinded tests, dentists investigated the dental status of both groups. MAIN OUTCOME MEASURES: Maxillary sinus: bone thickness and volume on computed tomography; craniofacial anatomical features: linear and angular variables in lateral cephalometry; and dental evaluation: malocclusion class, teeth status, and alveolar bone height. RESULTS: Bony wall thickness of the maxillary sinus significantly increased in patients with CRS (P < .001) but showed no relationship with maxillary sinus volume. Maxillary sinus volume significantly decreased in patients with CRS (P = .001). Age and alveolar bone height had a negative effect on maxillary sinus volume in both groups. Abnormal teeth had no relationship with maxillary sinus volume in both groups but showed a negative effect on alveolar bone height in the CRS group (P = .02). Class II malocclusion associated with anterior movement of the maxilla significantly increased in the CRS group (P = .006). CONCLUSIONS: Regardless of CRS, maxillary sinus volume decreased with older age and increased with alveolar bone loss. Regarding craniofacial anatomical features, CRS may have an effect on malocclusion in adults.


Subject(s)
Face/anatomy & histology , Maxillary Sinus/pathology , Rhinitis/pathology , Sinusitis/pathology , Skull/anatomy & histology , Adult , Cephalometry , Chronic Disease , Humans , Malocclusion, Angle Class II/pathology , Organ Size , Retrospective Studies , Tomography, X-Ray Computed
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