PURPOSE: The purpose of this study is to establish the method generating human brain anatomical connectivity from Korean children and evaluating the network topological properties using small-world network analysis. MATERIALS AND METHODS: Using diffusion tensor images (DTI) and parcellation maps of structural MRIs acquired from twelve healthy Korean children, we generated a brain structural connectivity matrix for individual. We applied one sample t-test to the connectivity maps to derive a representative anatomical connectivity for the group. By spatially normalizing the white matter bundles of participants into a template standard space, we obtained the anatomical brain network model. Network properties including clustering coefficient, characteristic path length, and global/local efficiency were also calculated. RESULTS: We found that the structural connectivity of Korean children group preserves the small-world properties. The anatomical connectivity map obtained in this study showed that children group had higher intra-hemispheric connectivity than inter-hemispheric connectivity. We also observed that the neural connectivity of the group is high between brain stem and motorsensory areas. CONCLUSION: We suggested a method to examine the anatomical brain network of Korean children group. The proposed method can be used to evaluate the efficiency of anatomical brain networks in people with disease.
Brain ; Brain Stem ; Child ; Diffusion ; Humans

OBJECTIVES: Synchronous electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has been used to explore sleep stage dependent functional brain networks. Despite a growing number of sleep studies using EEG-fMRI, few studies have conducted network analysis on whole night sleep due to difficulty in data acquisition, artifacts, and sleep management within the MRI scanner. METHODS: In order to perform network analysis for whole night sleep, we proposed experimental procedures and data processing techniques for EEG-fMRI. We acquired 6–7 hours of EEG-fMRI data per participant and conducted signal processing to reduce artifacts in both EEG and fMRI. We then generated a functional brain atlas with 68 brain regions using independent component analysis of sleep fMRI data. Using this functional atlas, we constructed sleep level dependent functional brain networks. RESULTS: When we evaluated functional connectivity distribution, sleep showed significantly reduced functional connectivity for the whole brain compared to that during wakefulness. REM sleep showed statistically different connectivity patterns compared to non-REM sleep in sleep-related subcortical brain circuits. CONCLUSION: This study suggests the feasibility of exploring functional brain networks using sleep EEG-fMRI for whole night sleep via appropriate experimental procedures and signal processing techniques for fMRI and EEG.
Artifacts ; Brain ; Electroencephalography ; Magnetic Resonance Imaging ; Sleep Stages ; Sleep, REM ; Wakefulness

The limited literature on mental illness in end-stage kidney disease (ESKD) patients suggests that this disease is common and burdensome but underrecognized in clinical practice. This study aimed to analyze the prevalence of mental illness in ESKD patients. Methods: We assessed the prevalence and patterns of mental illnesses in a nationwide cohort of patients diagnosed with ESKD between January 1, 2008, and December 31, 2017. The risk of mental illness was evaluated using a multivariable Cox proportional hazards model. Results: A total of 70,079 patients met all study inclusion criteria. A total of 28.3% of patients had mental illness, and the specific distribution was as follows: depression, 16.8%; anxiety, 20.0%; somatoform/conversion disorder, 0.9%; stress reaction/adjustment disorder, 2.5%; and substance abuse disorder, 0.6%. The frequency of mental illness was highest in patients on hemodialysis (HD), followed by patients on peritoneal dialysis (PD) and kidney transplant (KT) patients. The peak rate of mental illness in HD and PD patients was reached 1 to 2 years after renal replacement therapy initiation, but the peak rate of most mental illnesses in KT patients occurred before surgery. The prevalence of depression was 2.19 times higher in HD patients and 1.97 times higher in PD patients than in KT patients. Conclusion: ESKD patients are at high risk of mental illness, and the prevalence of mental illness is highest in HD patients. Since the onset of mental illness occurs around the initiation of renal replacement therapy, clinicians need to pay attention to mental illness when treating ESKD patients.

Background: Psoriasis is a complex and heterogeneous disease that widely affects a patient’s life. Biological therapy is usually prescribed in patients with severe psoriasis that do not respond to conventional treatment. However, data on the specific patient characteristics receiving biologics are still unavailable. Objective: To classify patients with psoriasis into subgroups with distinct phenotypes through cluster analysis, and to evaluate the differences between the clusters to predict disease prognosis by examining the response to biological therapy. Methods: The clinical characteristics of the patients with psoriasis were investigated and categorized using hierarchical cluster analysis. After clustering, the clinical characteristics of the patients were compared and the initiation of treatment with biologics according to the clusters were evaluated. Results: A total of 361 patients with psoriasis were classified into two clusters using 16 distinct clinical phenotypes. Group 1 (n=202) consisted of male smokers and alcohol users with higher psoriasis area and severity index (PASI), older age of onset, higher body mass index, and comorbidities including psoriatic arthritis, hypertension, and diabetes when compared to group 2 (n=159). Group 1 had a significantly higher probability of biological treatment initiation than group 2 (p=0.039). The measured risk factors for the initiation of biologics compared were PASI (p<0.001) and nail involvement (p=0.022). Conclusion Cluster analysis classified patients with psoriasis into two subgroups according to their clinical characteristics. Predicting the disease prognosis using a combination of specific clinical parameters may aid in the management of the disease.

Purpose: To evaluate the risk factors and effects of fluctuations in oxygen saturation on the occurrence and severity of retinopathy of prematurity (ROP). Methods: From January 1, 2013 to January 31, 2020, 260 patients hospitalized in the neonatal intensive care unit of Ajou University Hospital were retrospectively analyzed. Results: Sixty-six patients (25%) were diagnosed with ROP; of them 39 required treatment. In the multivariate regression analysis of ROP severity, the odds ratio (OR) of gestational age was 0.32 (95% confidence interval [CI], 0.22 to 0.47; P<0.0001). The OR of saturation of peripheral oxygen (SpO2) fluctuations at the 4th week after birth was 1.02 (95% CI, 1.02 to 1.12; P=0.041). Conclusion SpO2 fluctuations in premature infants younger than 30 weeks’ gestational age affects ROP severity, especially at the 4th week of life.

Purpose: To evaluate the risk factors and effects of fluctuations in oxygen saturation on the occurrence and severity of retinopathy of prematurity (ROP). Methods: From January 1, 2013 to January 31, 2020, 260 patients hospitalized in the neonatal intensive care unit of Ajou University Hospital were retrospectively analyzed. Results: Sixty-six patients (25%) were diagnosed with ROP; of them 39 required treatment. In the multivariate regression analysis of ROP severity, the odds ratio (OR) of gestational age was 0.32 (95% confidence interval [CI], 0.22 to 0.47; P<0.0001). The OR of saturation of peripheral oxygen (SpO2) fluctuations at the 4th week after birth was 1.02 (95% CI, 1.02 to 1.12; P=0.041). Conclusion SpO2 fluctuations in premature infants younger than 30 weeks’ gestational age affects ROP severity, especially at the 4th week of life.

This study investigates the potential of cone-beam computed tomography (CBCT)-generated cephalograms as a replacement for conventional lateral cephalograms (LCs) in children and adolescents. This retrospective study included 60 individuals, equally divided into permanent and mixed dentition groups. Both groups underwent conventional LCs and CBCT scans on the same day. LCs were then derived from CBCT scans. The same examiner performed digital measurements twice, with a week’s interval, identifying landmarks and obtaining 7 angular and 5 linear measurements. In the permanent dentition group, significant differences were observed between the two imaging modalities for 6 angular and 2 linear measurements. In the mixed dentition group, significant differences were observed for 3 angular and 2 linear measurements. However, none of these differences exceeded the clinically acceptable limit of 2.0º or 2.0 mm. No significant differences in any measurement were found between the two groups (p < 0.05). CBCT-generated LCs demonstrated comparable results with good reliability in both dentition groups, suggesting their potential as suitable alternatives for children and adolescents who require CBCT for clinical purposes.

This study investigates the potential of cone-beam computed tomography (CBCT)-generated cephalograms as a replacement for conventional lateral cephalograms (LCs) in children and adolescents. This retrospective study included 60 individuals, equally divided into permanent and mixed dentition groups. Both groups underwent conventional LCs and CBCT scans on the same day. LCs were then derived from CBCT scans. The same examiner performed digital measurements twice, with a week’s interval, identifying landmarks and obtaining 7 angular and 5 linear measurements. In the permanent dentition group, significant differences were observed between the two imaging modalities for 6 angular and 2 linear measurements. In the mixed dentition group, significant differences were observed for 3 angular and 2 linear measurements. However, none of these differences exceeded the clinically acceptable limit of 2.0º or 2.0 mm. No significant differences in any measurement were found between the two groups (p < 0.05). CBCT-generated LCs demonstrated comparable results with good reliability in both dentition groups, suggesting their potential as suitable alternatives for children and adolescents who require CBCT for clinical purposes.

This study investigates the potential of cone-beam computed tomography (CBCT)-generated cephalograms as a replacement for conventional lateral cephalograms (LCs) in children and adolescents. This retrospective study included 60 individuals, equally divided into permanent and mixed dentition groups. Both groups underwent conventional LCs and CBCT scans on the same day. LCs were then derived from CBCT scans. The same examiner performed digital measurements twice, with a week’s interval, identifying landmarks and obtaining 7 angular and 5 linear measurements. In the permanent dentition group, significant differences were observed between the two imaging modalities for 6 angular and 2 linear measurements. In the mixed dentition group, significant differences were observed for 3 angular and 2 linear measurements. However, none of these differences exceeded the clinically acceptable limit of 2.0º or 2.0 mm. No significant differences in any measurement were found between the two groups (p < 0.05). CBCT-generated LCs demonstrated comparable results with good reliability in both dentition groups, suggesting their potential as suitable alternatives for children and adolescents who require CBCT for clinical purposes.

Background: Age-adjusted bone mineral density (BMD) in postmenopausal women decreases in developed countries whereas incidence of osteoporotic fracture decreases or remains stable. We investigated secular trends of bone density from 2008 to 2017 among different age groups of postmenopausal women. Methods: We analyzed BMD data obtained from health check-ups of 4,905 postmenopausal women during three survey cycles from 2008 to 2017. We divided them into 3 groups by age (50–59 years, 60–69 years, and 70 years or more) and observed the transition of lumbar and femoral BMD in each group, before and after adjusting for variables that may affect BMD. Results: Age-adjusted BMD, bone mineral content (BMC), and T-score demonstrated a declining trend over the survey period at lumbar spine (−2.8%), femur neck (−3.5%) and total femur (−4.3%), respectively. In the analysis for the age groups, the BMD, BMC, and T-score presented linear declining trend (−6.1%) in younger postmenopausal women while women aged over 70 or more showed linear increasing trends (+6.3%) at lumbar spine during the survey period. Femoral neck and total femur BMD demonstrated a declining linear trend only in the 50–59 and 60–69 years groups (−5.5%, −5.2%, respectively), but not in the 70 years or more group. Conclusion BMD in younger postmenopausal women has decreased considerably but has increased or plateaued in elderly women. This discordance of BMD trends among different age groups may contribute to decreased incidence of osteoporotic fracture despite a recent declining BMD trend in postmenopausal women.