• Journal of Korean Neurosurgical Society
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• v.66 no.2
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• pp.199-204
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• 2023

It is critical to identify the ruptured cerebral arteriovenous malformations (AVMs) for secondary prevention. However, there are rare cases unidentified on the radiological evaluation. We report on a patient with the delayed appearance of radiologically occult AVM as a probable cause of the previous intracerebral hemorrhage (ICH). An 18-year-old male patient presented with a right temporal ICH. The preoperative radiological examination did not reveal any causative lesions. Because of the intraoperative findings suggesting an AVM, however, only hematoma was evacuated. Disappointedly, there were no abnormal findings on postoperative and follow-up radiographic examinations. Eleven years later, the patient presented with an epileptic seizure, and an AVM was identified in the right temporal lobe where ICH had occurred before. The patient underwent partial glue embolization followed by total surgical resection of the AVM and anterior temporal lobe. Based on the literature review published in the era of magnetic resonance imaging, common clinical presentation of radiologically occult AVMs included headache and seizure. Most of them were confirmed by pathologic examination after surgery. In cases of the ICH of unknown etiology in young patients, long-term follow-up should be considered.

• ETRI Journal
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• v.45 no.3
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• pp.543-550
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• 2023

Electrostatic discharge (ESD) testing for human body model tests is an essential part of the reliability evaluation of electronic/electrical devices and components. However, global environmental concerns have called for the need to replace the mercury-wetted relay switches, which have been used in ESD testers. Therefore, herein, we propose an ESD tester using metal oxide semiconductor-controlled thyristor (MCT) devices with a significantly higher rising rate of anode current (di/dt) characteristics. These MCTs, which have a breakdown voltage beyond 3000 V, were developed through an in-house foundry. As a replacement for the existing mercury relays, the proposed ESD tester with the developed MCT satisfies all the requirements stipulated in the JS-001 standard for conditions at or below 2000 V. Moreover, unlike traditional relays, the proposed ESD tester does not generate resonance; therefore, no additional circuitry is required for resonant removal. To the best of our knowledge, the proposed ESD tester is the first study to meet the JS-001 specification by applying a new switch instead of an existing mercury-wetted relay.

• Smart Structures and Systems
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• v.31 no.5
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• pp.501-516
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• 2023

Dynamic irregularity and acceleration of bridges subjected to high-speed trains provide crucial information for comprehensive evaluation of the health state of under-track structures. This paper proposes a novel approach for real-time estimation of vertical track dynamic irregularity and bridge acceleration using deep generative adversarial network (GAN) and vibration data from in-service train. The vehicle-body and bogie acceleration responses are correlated with the two target variables by modeling train-bridge interaction (TBI) through least squares generative adversarial network (LSGAN). To realize supervised learning required in the present task, the conventional LSGAN is modified by implementing new loss function and linear activation function. The proposed approach can offer pointwise and accurate estimates of track dynamic irregularity and bridge acceleration, allowing frequent inspection of high-speed railway (HSR) bridges in an economical way. Thanks to its applicability in scenarios of high noise level and critical resonance condition, the proposed approach has a promising prospect in engineering applications.

• The Journal of the Society of Stroke on Korean Medicine
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• v.18 no.1
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• pp.55-65
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• 2017

■ Objectives Atrial fibrillation is the most common cause of cardioembolic stroke. Of the 44 ischemic stroke patients with atrial fibrillation who were hospitalized in hospital of Korean Medicine from July 1, 2014 to June 30, 2017, we selected 39 patients who have had Magnetic Resonance Angiography. We divided them into Atrial Fibrillation group with no stenosis or less than 50% stenosis in the ipsilateral artery of the lesion and Artery to Artery Embolism group with more than 50% stenosis or occlusion in the ipsilateral artery of the lesion. ■ Methods Clinical characteristics, examination and evaluation tools were collected from the patient's electronic medical records. CHADS2, Initial National Institutes of Health Stroke Scale, 8-item Stroke Scale and Improved 8-item Stroke Scale Number were checked. ■ Results & Atrial Fibrillation group showed differences in age, brain lesion location, vascular lesion, Conclusion initial National Institutes of Health Stroke Scale, initial 8-item Stroke Scale and progress compared to Artery to Artery Embolism group.

• Journal of Veterinary Clinics
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• v.40 no.3
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• pp.225-229
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• 2023

In three dogs showing cerebellar ataxia, the onset of clinical signs varied from a young age of five months to age 13 years. Qualitative magnetic resonance imaging (MRI) revealed various degrees of cerebellar atrophy, and a tentative diagnosis of cerebellar cortical degeneration was made. Quantitative analysis using the brainstem to the cerebellar cross-sectional area ratio (BS:CBM ratio) and T2-signal intensity histograms were obtained to perform an objective evaluation. These techniques have the advantage of being easy and fast to evaluate. These quantitative analyses revealed the severity of cerebellar cortical degeneration in the three dogs as mild, moderate, and severe. Dogs 2 and 3 were identified as abnormal on the relative cerebrospinal fluid (CSF) space using T2-signal intensity histograms but were normal on the BS:CBM ratio. This suggests that the T2-signal intensity histograms may have higher sensitivity than BS:CBM ratio.

• Imaging Science in Dentistry
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• v.53 no.4
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• pp.283-289
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• 2023

The apnea-hypopnea index is widely regarded as a measure of the severity of obstructive sleep apnea (OSA), a condition characterized by recurrent episodes of apnea or hypopnea during sleep that induce airway collapse. OSA is a catastrophic problem due to the wide range of health issues it can cause, including cardiovascular disease and memory loss. This review was conducted to clarify the roles of various imaging modalities, particularly cone-beam computed tomography (CBCT), in the diagnosis of and preoperative planning for OSA. Unfortunately, 2-dimensional imaging techniques yield insufficient data for a comprehensive diagnosis, given the complex anatomy of the airway. Three-dimensional (3D) imaging is favored as it more accurately represents the patient's airway structure. Although computed tomography and magnetic resonance imaging can depict the actual 3D airway architecture, their use is limited by factors such as high radiation dose and noise associated with the scans. This review indicates that CBCT is a low-radiation imaging technique that can be used to incidentally identify patients with OSA, thereby facilitating early referral and ultimately enhancing the accuracy of surgical outcome predictions.

• Korean Journal of Radiology
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• v.25 no.1
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• pp.86-102
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• 2024

Early diagnosis, accurate assessment, and localization of peritoneal metastasis (PM) are essential for the selection of appropriate treatments and surgical guidance. However, available imaging modalities (computed tomography [CT], conventional magnetic resonance imaging [MRI], and 18fluorodeoxyglucose positron emission tomography [PET]/CT) have limitations. The advent of new imaging techniques and novel molecular imaging agents have revealed molecular processes in the tumor microenvironment as an application for the early diagnosis and assessment of PM as well as real-time guided surgical resection, which has changed clinical management. In contrast to clinical imaging, which is purely qualitative and subjective for interpreting macroscopic structures, radiomics and artificial intelligence (AI) capitalize on high-dimensional numerical data from images that may reflect tumor pathophysiology. A predictive model can be used to predict the occurrence, recurrence, and prognosis of PM, thereby avoiding unnecessary exploratory surgeries. This review summarizes the role and status of different imaging techniques, especially new imaging strategies such as spectral photon-counting CT, fibroblast activation protein inhibitor (FAPI) PET/CT, near-infrared fluorescence imaging, and PET/MRI, for early diagnosis, assessment of surgical indications, and recurrence monitoring in patients with PM. The clinical applications, limitations, and solutions for fluorescence imaging, radiomics, and AI are also discussed.

• Journal of the Korean Society of Radiology
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• v.84 no.3
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• pp.565-585
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• 2023

Perianal fistula is a common inflammatory condition in the general population and affects the area around the anal canal. Although most cases are benign, they cause serious morbidity and require surgical treatment due to a high risk of recurrence. MR imaging is a gold standard technique for the evaluation of perianal fistulas and provides accurate information on the anatomy of the anal canal, its relationship to the anal sphincter complex, accurate identification of secondary tracts or abscesses, and reporting associated complications. MR imaging can help monitor treatment effects and determine treatment methods. Crohn's disease-related fistulas often require medical rather than surgical treatment. The radiologist is required to know the anatomy and MR imaging findings of the perianal fistula to present an accurate diagnosis to the clinician.

• Dementia and Neurocognitive Disorders
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• v.22 no.3
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• pp.87-99
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• 2023

Background and Purpose: According to the amyloid cascade hypothesis, fibrillary amyloid-beta load in the brain causes Alzheimer's disease (AD) with toxic effects. Recently, perivascular spaces (PVSs), fluid-filled cavities around small penetrating arterioles and venules in the brain, and the glymphatic system relationship with type 2 diabetes mellitus (DM2) and AD has been an important research topic from a physiopathological point of view. There are two types of PVSs that are associated with sporadic atherosclerosis and cerebral amyloid angiopathy. In this study, we evaluated the relationship between the number and localization of enlarged PVSs in AD. Methods: A total of 254 patients with AD and 125 healthy controls were included in this study All the patients were evaluated with neurological and cognitive examinations and magnetic resonance imaging (MRI). PVSs on MRI were graded by recording their number and location. The study was a retrospective study. Results: In our study, the number of white matter convexity-central semiovale localized PVSs was higher in patients than in the control group. In addition, the number of PVSs in this localization score was higher in patients with DM2. Cerebral PVS counts were higher in patients with AD than in the control group. Conclusions: These results suggest the important role of cerebral amyloid angiopathy, one of the vascular risk factors, and the glymphatic system in the pathogenesis of AD. In addition, the results of our study suggest that the evaluation of PVSs levels, especially at the (centrum semiovale), using imaging studies in AD is a potential diagnostic option.

• Korean Journal of Veterinary Service
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• v.47 no.2
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• pp.101-105
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• 2024

Three dogs (7-year-old, neutered male Chihuahua; case 1, 1-year-old, spayed female mixed breed; case 2, 10-month-old, female Maltese; case 3) were referred to Jeju Veterinary Medicine Teaching Hospital for traumatic brain injury. All three patients exhibited abnormal neurological symptoms. The patients were diagnosed through medical history obtained from their caregivers and through computed tomography (CT) or magnetic resonance imaging (MRI) scans. Structural brain abnormalities were observed in two dogs through CT scans and in one dog through MRI. Decompression therapy with mannitol was administered to all three dogs. Case 1, which showed CT findings of pulmonary hemorrhage but no significant brain injury, and case 2, which had mild brain damage on CT imaging, showed improvement in neurological symptoms and gait abnormalities after decompression therapy. However, case 3, which showed suspected brain hemorrhage and brain edema on MRI, did not respond to decompression therapy and was euthanized one month later. Imaging evaluation through CT or MRI in dogs with traumatic brain injury can assist clinical veterinarians in assessing the prognosis of patients.