Hyung Suk Seo

Obstructive sleep apnea as a risk factor for cerebral white matter change in a middle-aged and older general population

STUDY OBJECTIVE Obstructive sleep apnea (OSA) contributes to the development of systemic hypertension, and hypertension strongly predicts the development of white matter change (WMC). Thus, it is plausible that OSA mediates WMC. The goal of the current study is to determine whether a contextual relationship exists between OSA and cerebral WMC. DESIGN Cross-sectional analyses conducted in a population-based study. SETTING Korean community-based sample from the Korean Genome and Epidemiology Study (KoGES) who attended examinations in 2011 at a medical center. PARTICIPANTS There were 503 individuals (mean ± SD, age 59.63 ± 7.48 y) who were free of previously diagnosed cardiovascular and neurologic diseases. MEASUREMENTS AND RESULTS Participants underwent 1-night polysomnography and were classified as no OSA (obstructive apnea-hypopnea index [AHI] < 5, n = 289), mild OSA (AHI 5-15, n = 161), and moderate to severe OSA (AHI ≥ 15, n = 53). WMC was identified with brain magnetic resonance imaging (MRI) and was found in 199 individuals (39.56%). Multivariate logistic regression analyses adjusted for covariates revealed that moderate to severe OSA was significantly associated with the presence of WMC (odds ratio [OR] 2.08, 95%, confidence interval [CI] 1.05-4.13) compared with no OSA. Additional adjustment of hypertension to the model did not alter the significance of the association (OR 2.03, 95% CI 1.02-4.05). CONCLUSIONS Moderate to severe OSA is an independent risk factor for WMC in middle-aged and older individuals. Thus, early recognition and treatment of OSA could reduce the risk of stroke and vascular dementia.

Obstructive sleep apnea as a risk factor for silent cerebral infarction

Previous studies have suggested that obstructive sleep apnea (OSA) may be a risk factor for stroke. In this study, we assessed that OSA is an independent risk factor of silent cerebral infarction (SCI) in the general population, and in a non‐obese population. This study recruited a total of 746 participants (252 men and 494 women) aged 50–79 years as part of the Korean Genome and Epidemiology Study (KoGES); they underwent polysomnography, brain magnetic resonance imaging and health screening examinations. SCI was assessed by subtypes and brain regions, and lacunar infarction represented lesions <15 mm in size in the penetrating arteries. Moderate–severe OSA was determined by apnea–hypopnea index ≥15. The results indicated that 12.06% had moderate–severe OSA, 7.64% of participants had SCI and 4.96% had lacunar infarction. Moderate–severe OSA was associated positively with SCI [odds ratio (OR): 2.44, 95% confidence interval (CI): 1.03–5.80] and lacunar infarction (OR: 3.48, 95% CI: 1.31–9.23) in the age ≥65‐year group compared with those with non‐OSA. Additionally, in the basal ganglia, OSA was associated with an increase in the odds for SCI and lacunar infarction in all age groups, and especially in the ≥65‐year age group. In the non‐obese participants, OSA was also associated positively with SCI in the ≥65‐year age group, lacunar infarction in all age groups, and especially in the ≥65‐year age group. There was also a positive association with the basal ganglia. Moderate–severe OSA was associated positively with SCI and lacunar infarction in elderly participants. Treatment of OSA may reduce new first‐time cerebrovascular events and recurrences.

Enterovirus 71-related encephalomyelitis: usual and unusual magnetic resonance imaging findings

IntroductionMost enterovirus (EV) 71 infections manifest as mild cases of hand–foot–mouth disease (HFMD)/herpangina with seasonal variations, having peak incidence during the summer. Meanwhile, EV 71 may involve the central nervous system (CNS), causing severe neurologic disease. In many cases, enteroviral encephalomyelitis involves the central midbrain, posterior portion of the medulla oblongata and pons, bilateral dentate nuclei of the cerebellum, and the ventral roots of the cervical spinal cord, and the lesions show hyperintensity on T2-weighted and fluid-attenuation inversion recovery (FLAIR) images. Our goal was to review usual and unusual magnetic resonance (MR) findings in CNS involvement of enteroviral infection.MethodsAmong consecutive patients who had HFMD and clinically suspected encephalitis or myelitis and who underwent brain or spinal MR imaging, five patients revealed abnormal MR findings. Diffusion-weighted and conventional MR and follow-up MR images were obtained. From cerebrospinal fluid, stool, or nasopharyngeal swabs, EV 71 was confirmed in all patients.ResultsMR imaging studies of two patients showed hyperintensity in the posterior portion of the brainstem on T2-weighted and FLAIR images, which is the well-known MR finding of EV 71 encephalitis. The remaining three cases revealed unusual manifestations: leptomeningeal enhancement, abnormal enhancement along the ventral roots at the conus medullaris level without brain involvement, and hyperintensity in the left hippocampus on T2/FLAIR images.ConclusionEV 71 encephalomyelitis shows relatively characteristic MR findings; therefore, imaging can be helpful in radiologic diagnosis. However, physicians should also be aware of unusual radiologic manifestations of EV 71.

Cut-off value for needle washout thyroglobulin in athyrotropic patients†

The purpose of this study was to determine the appropriate cut‐off value for fine needle aspiration‐thyroglobulin (FNA‐Tg) associated with postoperative recurrences and validate the diagnostic efficacy of FNA‐Tg in patients after total thyroidectomy compared with concomitant cytology (C).

Amyloid Burden in Obstructive Sleep Apnea

To test the hypothesis that excessive amyloid deposition is a biological link between obstructive sleep apnea (OSA) and Alzheimers disease, we determined whether OSA increases cerebral amyloid burden, relative to controls, using Pittsburgh Compound B (PiB) PET imaging. The subjects were adult participants (age 50-65 years) from the Korean Genome and Epidemiology Study. Polysomnography, brain MRI including 3D images, and a detailed neuro-cognitive function test battery were done in 2011-2012. Nineteen OSA subjects (Apnea-Hypopnea Index [AHI] ≥15/h, 21.2±5.1/h; age 58.5±4.1 years; 9 male) and 19 controls (AHI 1.8±1.3/h; age 58.5±4.2 years; 9 male) underwent 60-min dynamic 11C-PiB PET. All subjects were right-handed with normal cognitive function and brain MRI. Controls were matched by age, gender, education, and APOE genotype. A voxel-wise comparison of PiB-PET images between the two groups was performed after spatial and count normalization with cerebellar gray matter as a reference. Covariates included the status of sleep duration, hypertension, diabetes, body mass index, exercise, depressive mood, smoking, and alcohol drinking. Cortical thickness on 3D MRI was also measured and compared between the two groups. The OSA group showed a higher PiB deposition in the right posterior cingulate gyrus and right temporal cortex (corrected p < 0.05). There was no area of higher uptake in the control compared with OSA. Regional differences in cortical thickness were not significant. The study suggests that OSA accelerates amyloid deposition and may contribute to the development or progression of Alzheimers disease.

Associations of Sleep Apnea, NRG1 Polymorphisms, Alcohol Consumption, and Cerebral White Matter Hyperintensities: Analysis with Genome-Wide Association Data.

STUDY OBJECTIVE There are few studies on gene-environment interactions with obstructive sleep apnea (OSA). Our study aimed to explore genetic polymorphisms associated with OSA using genome-wide association (GWA) data and evaluate the effects of relevant polymorphisms on the association between risk factors, including obesity and alcohol consumption, and OSA. We also investigated on these associations in relation to cerebral white matter hyperintensities (WMH) on magnetic resonance images. DESIGN A cross-sectional design. SETTING A polysomnography study embedded in a population-based cohort from the Korean Genome Epidemiology Study was conducted in 2011-2013. PARTICIPANTS 1,763 participants aged 48-78 years. RESULTS 251 individuals were identified to have OSA with an apnea-hypopnea index ≥ 15. A common polymorphism of neuregulin-1 gene (NRG1), rs10097555, was selected as the most suggestive locus associated with OSA (P value < 10(-5)) based on the results of GWA analysis in a matched case-control subsample (n = 470). Among 1,763 participants, we found that the presence of the NRG1 polymorphism is inversely associated with OSA (P value < 0.01) even after taking into account potential risk factors; the multivariate odds ratio (95% confidence interval) for the mutant alleles was 0.57 (0.39-0.82) compared with the wild-type. We observed that this association is modified by alcohol consumption (P < 0.05), not by obesity. We also observed that WMH are positively associated with OSA independent of the NRG1 polymorphism and alcohol consumption (P < 0.05). CONCLUSIONS These findings suggest that the neuregulin-1 gene (NRG1) may be involved in the etiological mechanisms of obstructive sleep apnea (OSA) and that carriers of a particular NRG1 mutation may be less likely to have OSA if they do not drink alcoholic beverages.

Gray Scale and Power Doppler Study of Biopsy-Proven Kikuchi Disease

Kikuchi disease is a benign, self‐limiting cause of cervical lymphadenopathy. It can show sonographic features similar to those of other common causes of lymphadenopathy. The purpose of this study was to characterize the sonographic features of Kikuchi disease that can contribute in differentiating between Kikuchi disease and other diseases causing cervical lymphadenopathy.

Association between high nocturnal blood pressure and white matter change and its interaction by obstructive sleep apnoea among normotensive adults

Objectives: A reverse dipping pattern, characterized by higher night-time blood pressure (BP) than daytime BP, is associated with the increased risk for cerebrovascular disease, cardiovascular events and all-cause mortality. However, little has known about the association between white matter change (WMC) and reverse dipping pattern, particularly in normotensive adults. We aimed to examine whether WMC is associated with BP dipping patterns as measured with a 24-h ambulatory BP monitoring and whether obstructive sleep apnoea (OSA) is involved in this relationship Methods: A total of 703 normotensive adults were from an ongoing longitudinal study in a general population. WMC was measured with brain MRI. BP dipping patterns were defined as the ratio of the change in night-time and daytime SBP. OSA was categorized with the apnoea-hypopnea index, as measured with polysomnography. To avoid the influence of hypertensive medications, we only included normotensive adults for the final analysis. To examine the associations between WMC and dipping patterns, we built logistic models. To elucidate the role of OSA, we also conducted both modification and mediation tests. Results: Reverse dipping pattern was significantly associated with WMC (odds ratio 1.49, 95% confidence interval 1.02–2.18). Further, OSA modified the association between dipping patterns and WMC (P = 0.0118). No mediation effect of OSA was assessed. Conclusion: In 703 normotensive adults, the reverse dipping pattern showed a significant association with WMC, after adjusting for covariates. Further, according to the presence of OSA, the association between reverse dipping and WMC was varied.

Comparison of ultrasonographic findings of biopsy-proven tuberculous lymphadenitis and kikuchi disease

Objective Although tuberculous lymphadenitis and Kikuchi disease are common causes of cervical lymphadenopathy in Asians and exhibit similar clinical manifestations, their treatment strategies are totally different. The purpose of this study was to identify ultrasonographic features that distinguish these two diseases. Materials and Methods This study was approved by the Institutional Review Board. The study included 77 patients with tuberculous lymphadenitis and 135 patients with Kikuchi disease. The sex and age distributions of the patients were analyzed. The size and shape of lymph nodes (LNs), presence of conglomeration, increased perinodal echogenicity, echogenic hilum, posterior neck involvement, internal calcification, patterns of internal necrosis, laterality of involved LNs, and hilar vascular patterns on ultrasonography were compared between the two groups. Multiple logistic regression analysis was conducted to identify independent findings to discriminate tuberculous lymphadenitis from Kikuchi disease. Finally, diagnostic accuracies were calculated using the independent findings. Results The presence of an echogenic hilum, internal calcification, patterns of internal necrosis, and LN hilar vascular structures on power Doppler ultrasonography were independent findings that discriminated tuberculous lymphadenitis from Kikuchi disease. The diagnostic accuracy of each of these four factors was 84.9% (181/212), 76.9% (163/212), 84% (178/212), and 89.2% (189/212), respectively. A combination of internal calcification and hilar vascular structures showed the best accuracy of 89.6% (190/212) (sensitivity, 86.7% [117/135]; specificity, 94.8% [73/77]) for diagnosing Kikuchi disease. Conclusion The presence of an echogenic hilum, internal calcification, pattern of internal necrosis, and LN hilar vascular structures are useful ultrasonographic findings to differentiate tuberculous lymphadenitis from Kikuchi disease.

Vascular Pattern Analysis on Microvascular Sonography for Differentiation of Pleomorphic Adenomas and Warthin Tumors of Salivary Glands

Pleomorphic adenomas and Warthin tumors are the most common salivary gland tumors. It is important to differentiate between them because at least a partial parotidectomy is necessary for pleomorphic adenomas, whereas enucleation is sufficient for Warthin tumors. This study aimed to evaluate the usefulness of vascular pattern analysis using microvascular sonography to differentiate between the tumors.