• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.705-711
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• 2022

A 46-year-old male with alcoholic liver cirrhosis underwent a transjugular intrahepatic portosystemic shunt (TIPS) for refractory ascites. On the 9th day after the procedure, he presented with melena and decreasing hemoglobin levels. Hemobilia due to fistula formation between the right intrahepatic bile duct and right hepatic artery was suspected on computed tomography. Angiography revealed a fistula of the small branches of the hepatic segmental arteries, and right intrahepatic bile duct was confirmed; embolization was successfully performed with a coil for the eighth segmental hepatic artery, a glue-lipiodol mixture for the fifth segmental hepatic artery, and gelfoam slurry for the right anterior hepatic artery. However, 2 days after embolization, the patient died owing to aggravated disseminated intravascular coagulopathy. When gastrointestinal bleeding occurs after TIPS, careful evaluation is immediately required, and hemobilia should be considered.

• Progress in Superconductivity and Cryogenics
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• v.7 no.4
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• pp.14-19
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• 2005

A transient numerical simulation was conducted to have variation of temperature on an element of resistive Superconducting Fault Current Limiter (SFCL) under quench condition. It is very important engineering information for an optimum design of cryogenic system for cooling of a resistive SFCL element. A bifilar coil for resistive SFCL for 10 MVA system was incorporated as a model in this numerical study. From the numerical simulation result, it was found that the averaged temperature on the shunt and Bi-2212 element at 500 kW, 100 ms was 711.1 K and 198.4 K respectively. The temperature variation with the change of the hot-spot size and time is also obtained. The maximum temperature was continuously increased in all cases until the hot-spot stops at 100ms and it was going down after then. Such as, the details of temperature distribution on the SFCL element obtained from this numerical study and it should be very valuable information on the decision of the cooling capacity of cryogenic system.

• Journal of the Korean Society of Radiology
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• v.81 no.1
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• pp.231-236
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• 2020

Duodenal varices can develop in patients with portal hypertension secondary to liver cirrhosis. Although upper gastrointestinal bleeding is often severe and fatal, the definite treatment or guideline has not been established. Although endoscopy is the primary therapeutic modality, the use of radiologic interventions, such as transjugular intrahepatic portosystemic shunt, balloon or vascular plug-assisted retrograde transvenous obliteration, and percutaneous transhepatic variceal obliteration, can be considered alternative treatment methods for duodenal varices. Herein, we report a case of duodenal varix in a patient with poor hepatic functional reserve and vascular anatomy, which are contraindications for an occlusion balloon or a vascular plug, successfully treated with coil-assisted retrograde transvenous obliteration.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.283-292
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• 2020

Current sensors that use a Hall element and Hall IC to measure the magnetic fields generated in steel silicon core gaps do not distinguish between direct and alternating currents. Thus, they are primarily used to measure direct current (DC) in industrial equipment. Although such sensors can measure the DC when installed in expensive equipment, ascertaining problems becomes difficult if the equipment is set up in an unexposed space. The control box is only opened during scheduled maintenance or when anomalies occur. Therefore, in this paper, a method is proposed for facilitating the safety management and maintenance of equipment when necessary, instead of waiting for anomalies or scheduled maintenance. A Bluetooth 4.0 low-energy current-sensor system based on near-field communication is used, which compensates for the nonlinearity of the current-sensor output signal using a piecewise linear model. The sensor is controlled using its generic attribute profile. Sensor nodes and cell phones used to check the signals obtained from the sensor at 50-A input currents showed an accuracy of ±1%, exhibiting linearity in all communications within the range of 0 to 50 A, with a stable output voltage for each communication segment.

• Journal of Korean Neurosurgical Society
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• v.43 no.6
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• pp.281-287
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• 2008

Objective : Cerebral vasospasm still remains a major cause of the morbidity and mortality, despite the developments in treatment of aneurysmal subarachnoid hemorrhage. The authors measured the utility and benefits of external lumbar cerebrospinal fluid (CSF) drainage to prevent the clinical vasospasm and its sequelae after endovascular coiling on aneurysmal subarachnoid hemorrhage in this randomized study. Methods : Between January 2004 and March 2006, 280 patients with aneurysmal subarachnoid hemorrhage were treated at our institution. Among them, 107 patients met our study criteria. The treatment group consisted of 47 patients who underwent lumbar CSF drainage during vasospasm risk period (about for 14 days after SAH), whereas the control group consisted of 60 patients who received the management according to conventional protocol without lumbar CSF drainage. We created our new modified Fisher grade on the basis of initial brain computed tomography (CT) scan at admission. The authors established five outcome criteria as follows : 1) clinical vasospasm; 2) GOS score at 1-month to 6-month follow-up; 3) shunt procedures for hydrocephalus; 4) the duration of stay in the ICU and total hospital stay; 5) mortality rate. Results : The incidence of clinical vasospasm in the lumbar drain group showed 23.4% compared with 63.3% of individuals in the control group. Moreover, the risk of death in the lumbar drain group showed 2.1 % compared with 15% of individuals in the control group. Within individual modified Fisher grade, there were similar favorable results. Also, lumbar drain group had twice more patients than the control group in good GOS score of 5. However, there were no statistical significances in mean hospital stay and shunt procedures between the two groups. IVH was an important factor for delayed hydrocephalus regardless of lumbar drain. Conclusion : Lumbar CSF drainage remains to playa prominent role to prevent clinical vasospasm and its sequelae after endovascular coiling on aneurysmal subarachnoid hemorrhage. Also, this technique shows favorable effects on numerous neurological outcomes and prognosis. The results of this study warrant clinical trials after endovascular treatment in patients with aneurysmal SAH.

• Tuberculosis and Respiratory Diseases
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• v.67 no.1
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• pp.52-58
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• 2009

Pulmonary arteriovenous malformation (PAVM) is a rare pulmonary vascular anomaly due to an abnormal communication between the pulmonary artery and vein. The most common presenting symptom is a dyspnea on exertion related to this right-to-left shunt. If left untreated, PAVM has been known to result in serious complications. Incomplete pulmonary capillary network can be the cause of cerebral abscesses and other noninfectious neurological complications, such as stroke and transient ischemic attacks due to paradoxic embolism Transcatheter embolotherapy, using coils or balloons, has replaced surgical resection as the treatment of choice for PAVM. However, the risk of device embolization has limited the use of coil embolotherapy, while the size of PAVM is huge. Recently, Amplatzer$^{(R)}$ Vascular Plug has been proposed as an alternative endovascular occlusion device for arteriovenous malformation. We report a case of 81-year-old male patient with a giant PAVM, which was successfully treated by transcatheter embolotherapy using the Amplatzer$^{(R)}$ Vascular Plug.

• Clinical and Experimental Pediatrics
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• v.53 no.12
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• pp.1012-1017
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• 2010

Purpose: Transcatheter closure has become an effective therapy in most patients with patent ductus arteriosus (PDA). However, there are difficulties in transcatheter closure of PDA in small children. We reviewed clinical outcomes of transcatheter closure of PDA in children weighing less than 10 kg in a single center. Methods: Between January 2003 and December 2009, 314 patients with PDA underwent transcatheter closure in our institute. Among them, 115 weighed less than 10 kg. All of these patients underwent transcatheter closure of PDA using either COOK Detachable $Coil^{(R)}$, PFM Nit-$Occlud^{(R)}$, or Amplatzer duct $occluder^{(R)}$. A retrospective review of the treatment results and complications was performed. Results: The mean age of patients was $9.1{\pm}5.9$ months (median, 8 months), and mean weight was $7.6{\pm}1.8kg$ (median, 7.8 kg). The mean diameter of PDA was $3.2{\pm}1.4mm$ (median, 3 mm). Complete occlusion occurred in 113 patients (98%). One patient was sent to surgery because of a failed attempt at device closure, and another patient had a small residual shunt after device placement. The average mean length of hospital stay was $3.0{\pm}3.3$ days, and mean follow-up duration was $21.0{\pm}19.6$ months. There were no major complications in any of the patients. Conclusion: Transcatheter closure of PDA is considered safe and efficacious in infants weighing less than 10 kg. With sufficient experience and further effort, transcatheter closure of PDA can be accepted as the gold standard of treatment for this group of patients.

• Journal of Korean Neurosurgical Society
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• v.65 no.5
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• pp.688-696
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• 2022

Objective : Transvenous embolization (TVE) via an occluded inferior petrosal sinus (IPS) in a cavernous sinus dural arteriovenous fistula (CSDAVF) is challenging, often requiring navigation of a microcatheter through resistive obstacles between the occluded IPS and shunted pouch (SP), although the reopening technique was successfully performed. We report five cases of successful access to the cavernous sinus (CS) or SP using the rigid-tipped microguidewire such as chronic total occlusion (CTO) wire aiming to share our initial experience with this wire. Methods : In this retrospective study, four patients with CSDAVF underwent five procedures using the CTO wire puncture during transfemoral transvenous coil embolization. Puncture success, shunt occlusion, and complications including any hemorrhage and cranial nerve palsy were evaluated. Results : Despite successful access through the occluded IPS, further entry into the target area using neurointerventional devices was impossible due to a short-segment stricture before the CS (three cases) and a membranous barrier within the CS (two cases). However, puncturing these structures using the rigid-tipped microguidewire was successful in all cases. We could advance the microcatheter over the rigid-tipped microguidewire for the navigation to the SP and achieved complete occlusion of the SP without complications. Conclusion : The use of the rigid-tipped microguidewire in the TVE via the occluded IPS of the CSDAVF would be feasible and safe.

• Neonatal Medicine
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• v.18 no.1
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• pp.117-123
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• 2011

Purpose: Congenital intrahepatic portosystemic shunts are rare disease and clinically asymptomatic shunts may be detected by chance on ultrasonogram before and after birth. We studied clinical course, treatment and prognosis of congenital intrahepatic portosystemic shunt at prenatal or neonatal period. Methods: Medical records of 8 patients which were diagnosed in intrahepatic portosystemic shunt in Cheil General Hospital from 2006 through 2010 were reviewed retrospectively. Results: Eight patients with congenital intrahepatic portosystemic shunts were identified. Six patients were diagnosed at prenatal radiological screening, including three cases of intrauterine growth restriction and two cases of preterm baby. One case with increased serum ammonia underwent coil embolization. In four cases including one case that presented elevated direct bilirubin, shunts were closed spontaneously within 11th month after birth. Two patients were diagnosed on abdominal sonogram after birth because of elevated direct hyperbilirubinemia, all of whom presented intrauterine growth restriction. Closure of shunts was confirmed during 4th month to 6th month. Conclusion: Congenital intrahepatic portosystemic shunts are clinically asymptomatic mostly and spontaneous closure is expected within 2 years age. But occasionally they have severe complication, so clinical and radiological observation is needed. Specially in cases of intrauterine growth retardation without evident cause, the possible diagnosis of congenital intrahepatic portosystemic shunts should be considered and prenatal and postnatal examination should be performed. When prenatal diagnosis is made, fetal wellbeing should be monitored periodically until spontaneous closure of shunts.

• Clinical and Experimental Pediatrics
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• v.52 no.4
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• pp.488-493
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• 2009

Purpose : The aim of this study was to assess the efficacy and safety of recent-generation patent ductus arteriosus (PDA) closure devices applied by a new selection strategy according to the characteristics of each PDA. Methods : From February 2003 to January 2006, 138 patients underwent transcatheter closure of PDA (study group). According to the size and morphology of each ductus, a COOK Detachable Coil or 'flex' PFM Nit-Occlud was used for a small ductus (group 1, n=43); 'medium' PFM Nit-Occlud (group 2, n=49) for a moderate ductus; and an Amplatzer Duct Occluder (group 3, n=46) for a large ductus. The 83 patients who underwent transcatheter closure of PDA from February 2000 to January 2003 were defined as the comparison group. The Qp/Qs ratio, pulmonary/aorta pressure ratio, and MD of the ductus were compared. Immediate and follow-up results including residual shunts and complications were also evaluated and compared among groups. Results : In all 138 patients, complete occlusions were confirmed without major complications, while procedure failure (n=2, 2.2%), device embolization (n=1, 1.1%), and persistent residual shunt (n=4, 4.5%) were documented in the comparison group. Total complication rates were lower in the study group than in the comparison group (study group, 1.4%; comparison group, 9.0%; P<0.05). Conclusion : A novel strategy adopting the merits of various recent-generation devices for transcatheter closure of PDA provides excellent clinical results with minimal risk.