Construction and validation of a brain magnetic resonance imaging template for normal older Koreans.

BACKGROUND: Spatial normalization to a standardized brain template is a crucial step in magnetic resonance imaging (MRI) studies. Brain templates made from sufficient sample size have low brain variability, improving the accuracy of spatial normalization. Using population-specific template improves accuracy of spatial normalization because brain morphology varies according to ethnicity and age. METHODS: We constructed a brain template of normal Korean elderly (KNE200) using MRI scans 100 male and 100 female aged over 60 years old with normal cognition. We compared the deformation after spatial normalization of the KNE200 template to that of the KNE96, constructed from 96 cognitively normal elderly Koreans and to that of the brain template (OCF), constructed from 434 non-demented older Caucasians to examine the effect of sample size and ethnicity on the accuracy of brain template, respectively. We spatially normalized the MRI scans of elderly Koreans and quantified the amount of deformations associated with spatial normalization using the magnitude of displacement and volumetric changes of voxels. RESULTS: The KNE200 yielded significantly less displacement and volumetric change in the parahippocampal gyrus, medial and posterior orbital gyrus, fusiform gyrus, gyrus rectus, cerebellum and vermis than the KNE96. The KNE200 also yielded much less displacement in the cerebellum, vermis, hippocampus, parahippocampal gyrus and thalamus and much less volumetric change in the cerebellum, vermis, hippocampus and parahippocampal gyrus than the OCF. CONCLUSION: KNE200 had the better accuracy than the KNE96 due to the larger sample size and was far accurate than the template constructed from elderly Caucasians in elderly Koreans.

Association of the Irregular 3-Dimensional Shape of White Matter Hyperintensities with Cognitive Function.

INTRODUCTION: The irregular shapes of white matter hyperintensities (WMHs) are associated with poor cognitive function, diabetes, or lacunes. However, the association between the WMH shape and dementia remains understudied. We investigated the association between the calculated shape index of WMH and the diagnosis of dementia and cognitive function. METHODS: The inverse sphericity index (ISIWMH) and volume of WMHs (VOLWMH) were compared among 82 participants with normal cognition, 82 with Alzheimer's dementia (AD), and 82 with subcortical vascular dementia (SVD). We examined the associations of ISIWMH and VOLWMH with the modified Hachinski Ischemic Score (mHIS), diagnosis of AD and SVD, and cognitive test scores, using linear, multinomial, or hierarchical linear regression models. RESULTS: The mHIS was associated with both ISIWMH (ß = 0.326, p < 0.001) and VOLWMH (ß = 0.299, p < 0.001). Both ISIWMH and VOLWMH were associated with the SVD diagnosis (odds ratio [OR] = 2.685, p = 0.002, ISIWMH; OR = 2.597, p = 0.005, VOLWMH), but not with AD. The SVD diagnosis was better explained when the multinomial regression model included both ISIWMH and VOLWMH instead of VOLWMH alone (χ2 = 20.768, df = 2, p < 0.001). The Trail Making Test-D (TMT-D) scores of the SVD patients were associated with both ISIWMH (ß = 0.308) and VOLWMH (ß = 0.293). CONCLUSION: An irregular WMH shape may be associated with the high cerebrovascular component of cognitive impairment and the diagnosis and low cognitive flexibility of SVD, which may improve the prediction of SVD diagnosis when used in combination with WMH volume.

Construction and validation of a cerebral white matter hyperintensity probability map of older Koreans.

BACKGROUND AND PURPOSE: Although two white matter hyperintensity (WMH) probability maps of healthy older adults already exist, they have several limitations in representing the distribution of WMH in healthy older adults, especially Asian older adults. We constructed and validated a WMH probability map (WPM) of healthy older Koreans and examined the age-associated differences of WMH. METHODS: We constructed WPM using development dataset that consisted of high-resolution 3D fluid-attenuated inversion recovery images of 5 age groups (60-64 years, 65-69 years, 70-74 years, 75-79 years, and 80+ years). Each age group included 30 age-matched men and women each. We tested the validity of the WPM by comparing WMH ages estimated by the WPM and the chronological ages of 30 healthy controls, 30 hypertension patients, and 30 S patients. RESULTS: Older age groups showed a higher volume of WMH in both hemispheres (p < 0.001). About 90% of the WMH were periventricular in all age groups. With advancing age, the peak of the distance histogram from the ventricular wall of the periventricular WMH shifted away from the ventricular wall, while that of deep WMH shifted toward the ventricular wall. The estimated WMH ages were comparable to the chronological ages in the healthy controls, while being higher than the chronological ages in hypertension and stroke patients. CONCLUSIONS: This WPM may serve as a standard atlas in research on WMH of older adults, especially Asians.

Identification of Alzheimer's disease using a convolutional neural network model based on T1-weighted magnetic resonance imaging.

The classification of Alzheimer's disease (AD) using deep learning methods has shown promising results, but successful application in clinical settings requires a combination of high accuracy, short processing time, and generalizability to various populations. In this study, we developed a convolutional neural network (CNN)-based AD classification algorithm using magnetic resonance imaging (MRI) scans from AD patients and age/gender-matched cognitively normal controls from two populations that differ in ethnicity and education level. These populations come from the Seoul National University Bundang Hospital (SNUBH) and Alzheimer's Disease Neuroimaging Initiative (ADNI). For each population, we trained CNNs on five subsets using coronal slices of T1-weighted images that cover the medial temporal lobe. We evaluated the models on validation subsets from both the same population (within-dataset validation) and other population (between-dataset validation). Our models achieved average areas under the curves of 0.91-0.94 for within-dataset validation and 0.88-0.89 for between-dataset validation. The mean processing time per person was 23-24 s. The within-dataset and between-dataset performances were comparable between the ADNI-derived and SNUBH-derived models. These results demonstrate the generalizability of our models to different patients with different ethnicities and education levels, as well as their potential for deployment as fast and accurate diagnostic support tools for AD.

Smaller pineal gland is associated with rapid eye movement sleep behavior disorder in Alzheimer's disease.

BACKGROUND: To investigate the association between pineal gland volume and symptoms of rapid eye movement (REM) sleep behavior disorder (RBD) in Alzheimer's disease (AD) patients without any feature of dementia with Lewy bodies. METHODS: We enrolled 296 community-dwelling probable AD patients who did not meet the diagnostic criteria for possible or probable dementia with Lewy bodies. Among them, 93 were amyloid beta (Aß) positive on 18F-florbetaben amyloid brain positron emission tomography. We measured RBD symptoms using the REM Sleep Behavior Disorder Screening Questionnaire (RBDSQ) and defined probable RBD (pRBD) as the RBDSQ of 5 or higher. We manually segmented pineal gland on 3T structural T1-weighted brain magnetic resonance imaging. RESULTS: The participants with pRBD had smaller pineal parenchyma volume (VPP) than those without pRBD (p <  0.001). The smaller the VPP, the more severe the RBD symptoms (p <  0.001). VPP was inversely associated with risk of prevalent pRBD (odds ratio = 0.909, 95% confidence interval [CI] = 0.878-0.942, p <  0.001). Area under the receiver operator characteristic curve for pRBD of VPP was 0.80 (95% CI = 0.750-0.844, p <  0.0001). These results were not changed when we analyzed the 93 participants with Aß-positive AD separately. CONCLUSIONS: In AD patients, reduced pineal gland volume may be associated with RBD.

Hippocampus Mediates the Effect of Emotional Support on Cognitive Function in Older Adults.

BACKGROUND: Despite strong evidence that emotional support has a protective effect on cognitive decline, the neural basis for how an individual's emotional support is associated with cognition is unknown. We investigated if the hippocampus mediates the relationship between emotional support and cognition in older adults. METHOD: Four hundred and ten nondemented Korean older adults were classified into two groups according to their Medical Outcomes Study-Social Support Survey emotional support scores: the poor emotional support (score ≤ 25th percentile of entire sample) and normal emotional support (score > 25th percentile of entire sample) groups. Cognitive function was assessed using the Verbal Memory Score and Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet Neuropsychological Assessment Battery total score (CERAD-TS). Left and right hippocampal volume were obtained using 3T T1-weighted magnetic resonance images. Mediation analyses were conducted. RESULTS: In the association of emotional support with Verbal Memory Score, left hippocampal volume played a mediating role (indirect effect = 0.40, SE = 0.21, bias-corrected 95% confidence interval = 0.04, 0.86). In the association of emotional support with CERAD-TS, both left (indirect effect = 0.82, SE = 0.45, bias-corrected 95% confidence interval = 0.09, 1.83) and right (indirect effect = 0.51, SE = 0.32, bias-corrected 95% confidence interval = 0.02, 1.24) HPVs played mediating roles. CONCLUSIONS: The hippocampus may mediate the association between emotional support and cognition. Higher levels of emotional support may be associated with better verbal memory and global cognition via larger HPV.

Seeding of osteosarcoma in the biopsy tract of a patient with multifocal osteosarcoma.

We report a case of multifocal osteosarcoma in a 7-year-old boy who developed iatrogenic seeding of tumor along the biopsy tract. The results of the plain radiograph, CT, and histopathological correlation are presented.