• Korean Journal of Radiology
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• v.24 no.5
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• pp.444-453
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• 2023

Objective: Meningeal lymphatic vessels are predominantly located in the parasagittal dural space (PSD); these vessels drain interstitial fluids out of the brain and contribute to the glymphatic system. We aimed to investigate the ability of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in assessing the dynamic changes in the meningeal lymphatic vessels in PSD. Materials and Methods: Eighteen participants (26-71 years; male:female, 10:8), without neurological or psychiatric diseases, were prospectively enrolled and underwent DCE-MRI. Three regions of interests (ROIs) were placed on the PSD, superior sagittal sinus (SSS), and cortical vein. Early and delayed enhancement patterns and six kinetic curve-derived parameters were obtained and compared between the three ROIs. Moreover, the participants were grouped into the young (< 65 years; n = 9) or older (≥ 65 years; n = 9) groups. Enhancement patterns and kinetic curve-derived parameters in the PSD were compared between the two groups. Results: The PSD showed different enhancement patterns than the SSS and cortical veins (P < 0.001 and P < 0.001, respectively) in the early and delayed phases. The PSD showed slow early enhancement and a delayed wash-out pattern. The six kinetic curve-derived parameters of PSD was significantly different than that of the SSS and cortical vein. The PSD washout rate of older participants was significantly lower (median, 0.09; interquartile range [IQR], 0.01-0.15) than that of younger participants (median, 0.32; IQR, 0.07-0.45) (P = 0.040). Conclusion: This study shows that the dynamic changes of meningeal lymphatic vessels in PSD can be assessed with DCE-MRI, and the results are different from those of the venous structures. Our finding that delayed wash-out was more pronounced in the PSD of older participants suggests that aging may disturb the meningeal lymphatic drainage.

• Biomedical Science Letters
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• v.11 no.4
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• pp.555-559
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• 2005

Evaluate the triolein emulsion could disrupt the barriers and to suggest as an experimental model in blood-ocular barrier studies. Triolein emulsion was infused into the carotid artery in the experimental group ten cats. Normal saline was used in another the control group ten cats. Pre contrast and postcontrast T1-weighted MR images were obtained at 30 minutes and 3 hours after embolization. Signal intensities were evaluated in the anterior, posterior chamber and in the vitreus qualitatively and quantitatively. Postembolization 30 minutes MR images were not different from those of the control group. Postembolization 3 hour MR images demonstrated delayed contrast enhancement in the anterior chamber of the ipsilateral and contralateral eyeballs and in the posterior chamber of the ipsilateral eyeball. Delayed contrast enhancement of the posterior chamber of the ipsilateral eyeball was statistically significant (P<0.05). The present study demonstrated significant contrast enhancement in the posterior chamber with infusion of triolein emulsion and can be a model in blood-aqueous barrier studies.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.1
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• pp.1-6
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• 2016

Recently, proportion of the induction motor load is gradually increased. When a contingency in the power systems, it has been discovered phenomenon that the voltage is delayed recover caused mechanical characteristics of the induction motor load. It can be a serious impact on the voltage stability of the power system considering induction motor load. The scheme to mitigate this phenomenon tripping off the motors to prevent voltage drop and delayed voltage recovery on the load demand side. Fault induced delayed voltage recovery phenomenon is caused by stalling of small induction motor load in transmission level contingencies. In this paper, fault induced delayed voltage recovery phenomenon mitigation method implementation under voltage load shedding on the korean power system considering induction motor load.

• Investigative Magnetic Resonance Imaging
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• v.25 no.3
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• pp.197-200
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• 2021

Ramsay Hunt syndrome (RHS) is a disease caused by varicella-zoster virus (VZV) infection that can be diagnosed through clinical symptoms with or without imaging evaluations. The typical features of RHS on imaging evaluation include signal changes and enhancement in the internal auditory canal (IAC) nerves, and the labyrinthine segment of cranial nerve VII (CN VII) and cranial nerve VIII (CN VIII). In some patients, inner ear structure (cochlear and vestibular apparatus) is involved in RHS. Neurologic complications, such as encephalitis and meningitis, are rare in RHS, but are known to occur. Therefore, magnetic resonance imaging (MRI) is necessary to detect both abnormal signal intensity in the IAC, CN VII, CN VIII, inner and ear structure, and CNS complications. We report an RHS patient with CN VII, VIII, and leptomeningeal enhancement within the cerebellar folia on 10-min delayed, contrast-enhanced (CE), three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) imaging.

• Archives of Pharmacal Research
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• v.15 no.1
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• pp.20-29
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• 1992

Effects of squalene on cellular and non-specific immune responses and antitumor activity in mice were investigated. Cellular and non-specific immunological assay parameters adopted in the present study were delayed-type hypersensitivity reaction and resette forming cells (RFC) for cellular immunity, activities of natural killer (NK) cells and phagocyte for non-specific immunity. Squalene resulted in marked increases of cellular and non-specific immune functions and enhancement of host resistance to tumor challenge in dose-dependent manner.

• Clinical Endoscopy
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• v.56 no.4
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• pp.510-520
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• 2023

Background/Aims: We aimed to investigate (1) promising clinical findings for the recognition of focal type autoimmune pancreatitis (FAIP) and (2) the impact of endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-TA) on the diagnosis of FAIP. Methods: Twenty-three patients with FAIP were involved in this study, and 44 patients with resected pancreatic ductal adenocarcinoma (PDAC) were included in the control group. Results: (1) Multivariate analysis revealed that homogeneous delayed enhancement on contrast-enhanced computed tomography was a significant factor indicative of FAIP compared to PDAC (90% vs. 7%, p=0.015). (2) For 13 of 17 FAIP patients (76.5%) who underwent EUS-TA, EUS-TA aided the diagnostic confirmation of AIPs, and only one patient (5.9%) was found to have AIP after surgery. On the other hand, of the six patients who did not undergo EUS-TA, three (50.0%) underwent surgery for pancreatic lesions. Conclusions: Homogeneous delayed enhancement on contrast-enhanced computed tomography was the most useful clinical factor for discriminating FAIPs from PDACs. EUS-TA is mandatory for diagnostic confirmation of FAIP lesions and can contribute to a reduction in the rate of unnecessary surgery for patients with FAIP.

• Investigative Magnetic Resonance Imaging
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• v.17 no.1
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• pp.33-40
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• 2013

Purpose : To evaluate late gadolinium enhancement (LGE) pattern of left ventricular (LV) myocardium and presence or absence of LGE in other regions of the heart on cardiac magnetic resonance (CMR) imaging in patients diagnosed with cardiac amyloidosis. Materials and Methods: From 2009 to 2011, 9 patients who were suspected cardiac amyloidosis underwent CMR. We retrospectively analyzed the presence or absence of LGE and enhancement pattern in LV myocardium, and the presence or absence of LGE in other chambers as well. Also we measured interatrial septal thickness (IST), relative signal intensities of atrial septum and epicardial fat over the left atrial (LA) cavity on delayed enhanced images. MRI parameters in these patients were compared to those of control group of patients with ischemic heart disease by Wilcoxon rank sum test. Results: Of nine patients, LGE were found in 8; subendocardial circumferential pattern in 4 and diffuse pattern in 4. LGE in right ventricle was observed in 7. IST was significantly increased in patients with cardiac amyloidosis (P = 0.02). Ratio of atrial septum to LA cavity and ratio of epicardial fat to LA cavity showed a significant difference (P = 0.0002 and P = 0.0006, respectively). Conclusion: In LGE CMR, subendocardial or diffuse enhancement pattern is a typical finding for patients with cardiac amyloidosis. Atrial septum and epicardial fat show relatively increased signal intensities over LA blood cavity.

• Archives of Pharmacal Research
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• v.9 no.3
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• pp.183-187
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• 1986

Some of organophosphate pesticides which are the most heavily used in Korea, were examined for their effects on the murine immune system. Immunotoxicological assay parameters adaopted in this study were Arthus reaction for humoral immunity, delayed type hypersensitivity reaction for cell mediate immunity, carbon clearance for macrophage function and susceptiility to tumor challenge. Subchronic exposure of rodents to the pesticides resulted in the marked suppression of immune functions and enhancement of susceptibility to tumor challenge. Among the pesticides tested (fenitrothion, fenthion, diazinon and EPN), fenitrothion was the most suppressive in Arthus and delayed type hypersensitivity reaction.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.405-410
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• 2014

In this paper, we compare the quality of images reconstructed by a conventional delayed-sum (DS) algorithm and radiation pattern-based DS algorithm. In order to evaluate the quality of images, we apply the target-to-clutter ratio (TCR), which is commonly used in synthetic aperture radar (SAR) image assessment. The radiation pattern-based DS algorithm enhances the TCR of the image by focusing the target signals and preventing contamination of the radar scene. We first consider synthetic data obtained through GprMax2D/3D, a finite-difference time-domain (FDTD) forward solver. Experimental data of a 2-GHz bandwidth stepped-frequency signal are collected using a vector network analyzer (VNA) in an anechoic chamber setup. The radiation pattern-based DS algorithm shows a 6.7-dB higher TCR compared to the conventional DS algorithm.

• Annals of Clinical Neurophysiology
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• v.21 no.2
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• pp.98-101
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• 2019

A 64-year-old man presented with facial diplegia occurring 2 weeks after scrub typhus diagnosis. The serum scrub typhus antibody titer was elevated to 1:5120. Brain magnetic resonance imaging revealed contrast-enhancement of the signal for both facial nerves. He was administered prednisolone. After two weeks, the symptoms improved, and after one month, he completely recovered from facial diplegia. This is the first case in the literature in which the patient exhibited facial diplegia, a delayed complication, in scrub typhus. Facial diplegia should be considered a type of cranial nerve palsy that may occur as a delayed complication of scrub typhus.