• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.183-188
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• 2008

본 연구의 주요 목적은 기존의 연구에서 구축된 배타적 경제수역(EEZ) 해양자원정보시스템(MRIS)을 근간으로 다양한 해양자원의 정보를 효율적으로 표출하고 EEZ 관련 의사지원과 정책결정을 위한 GIS기반의 EEZ 정책결정지원시스템을 개발에 있다. 이를 위하여 기존에 구축된 MRIS를 이용하여 분산되어 관리되던 기존의 데이터와 매년 탐사 과정을 거쳐 추가되는 데이터의 관리를 위한 표준화를 수립하고 관리방안을 확정하였다. 또한, 기존에 개발된 다양한 해양데이터의 표출방안을 이용하여 EEZ 경계획정 협상 및 정책 결정에 있어 실질적 판단근거가 되는 EEZ에 대한 법령과 각국의 정책 및 EEZ 경계획정 사례 등을 데이터베이스화하였다. 나아가 GIS를 이용하여 표출된 공간데이터를 다양한 공간 검색과 공간분석 기능을 이용하여 분석함으로써 과학적인 방법으로 EEZ에 대한 중요정책 결정에도 활용하도록 하였다. 본 시스템을 이용하여 향후 EEZ 내 자원분포 및 지 역 별 경제성 비교와 쟁점지역에 대한 정확한 분석이 가능함에 따라 국가 간 협상에서 우리나라에 보다 유리한 협상결과를 도출하는데 기여가 클 것으로 판단된다. 아울러 주변국과 경계획정에 있어 유리한 협상 결과를 도출하기 위한 제반 정보의 제공과 함께 보다 효율적인 정책 수립을 위한 다양한 의사결정의 지원이 가능할 것으로 사료된다.

• Journal of Korean Neurosurgical Society
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• v.38 no.6
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• pp.425-430
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• 2005

Objective : Recently, the survival rate and prognosis of spontaneous intracerebral hemorrhage[S-ICH] has improved, and their enhanced survival has become associated with a consequent rise in the recurrence of S-ICH. The aim of this study is to improve the prevention of recurrent S-ICH. Methods : Between January 1999 and March 2004, we experienced 48 cases of recurrence. We classified the patients into the two groups; a double ICH group and a triple ICH group. We investigated their brain CTs, MRIs, cerebral angiographies, and medical records, retrospectively. Results : Majority of patients had the intervals at least 12 months, and most of patients underwent conservative treatment. The most common hemorrhage pattern of recurrence was ganglionic-ganglionic [basal ganglia - basal ganglia], and the second attack was contralateral side of the first attack in a large percentage of all patients. Prognosis of patients was worsened in recurrent attack. Nearly all patients had medical history of hypertension, and most patients have taken antihypertensive medication at the arrival of emergency room. Conclusion : In treating hypertension for S-ICH patients, we stress that blood pressure must be thoroughly controlled over a long period of time.

• Progress in Medical Physics
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• v.31 no.4
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• pp.189-193
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• 2020

An MR-based attenuation correction (MRAC) map plays an important role in quantitative positron emission tomography (PET) image evaluation in PET/magnetic resonance imaging (MRI) systems. However, the MRAC map is affected by the magnetic field inhomogeneity of MRIs. This study aims to evaluate the characteristics of MRAC maps of physical phantoms on PET/MRI images. Phantom measurements were performed using the Siemens Biograph mMR. The modular type physical phantoms that provide assembly versatility for phantom construction were scanned in a four-channel Body Matrix coil. The MRAC map was generated using the two-point Dixon-based segmentation method for whole-body imaging. The modular phantoms were scanned in compact and non-compact assembly configurations. In addition, the phantoms were scanned repeatedly to generate MRAC maps. The acquired MRAC maps show differently assigned values for void areas. An incorrect assignment of a void area was shown on a locally compact space between phantoms. The assigned MRAC values were distorted using a wide field-of-view (FOV). The MRAC values also differed after repeated scans. However, the erroneous MRAC values appeared outside of phantom, except for a large FOV. The MRAC map of the phantom was affected by phantom configuration and the number of scans. A quantitative study using a phantom in a PET/MRI system should be performed after evaluation of the MRAC map characteristics.

• Investigative Magnetic Resonance Imaging
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• v.26 no.2
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• pp.83-95
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• 2022

The purpose of this study was to establish and provide guidelines for the standardized acquisition and interpretation of diffusion-weighted magnetic resonance imaging (DW-MRI) to improve the image quality and reduce the variability of the results interpretation. The standardized protocol includes the use of high-resolution DW-MRI with advanced techniques and post-processing. The aim of the protocol is to increase the effectiveness of the medical image information exchange involved in the construction, activation, and exchange of clinical information for healthcare use. An organized interpretation form could make DW-MRIs' interpretation easier and more familiar. Herein, the authors briefly review the basic principles, optimized image acquisition, standardized interpretation guidelines, false negative and false positive cases of DW-MRI, and provide a standard interpretation form and examples of various cases to help users become more familiar with the DW-MRI.

• Clinics in Shoulder and Elbow
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• v.21 no.2
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• pp.82-86
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• 2018

Background: Although a common shoulder disease, there are no accepted classification criteria for frozen shoulder (FS). This study therefore aimed to evaluate the accuracy of the conventionally used FS classification system. Methods: Primary FS patients (n=168) who visited our clinic from January 2010 to July 2015 were included in the study. After confirming restrictions of the glenohumeral joint motion and absence of history of systemic disease, trauma, shoulder surgery, shoulder muscle weakness, or specific x-ray abnormalities, the Zuckerman and Rokito's classification was employed for diagnosing primary FS. Following clinical diagnosis, each patient underwent a shoulder magnetic resonance imaging (MRI) and blood tests (lipid profile, glucose, hemoglobin A1c, and thyroid function). Based on the results of the blood tests and MRIs, the patients were reclassified, using the criteria proposed by Zuckerman and Rokito. Results: New diagnoses were ascertained including blood test results (16 patients with diabetes, 43 with thyroid abnormalities, and 149 with dyslipidemia), and MRI revealed intra-articular lesions in 81 patients (48.2%). After re-categorization based on the above findings, only 5 patients (3.0%) were classified having primary FS. The remaining 163 patients (97.0%) had either undiagnosed systemic or intrinsic abnormalities (89 patients), whereas 74 patients had both. Conclusions: These findings demonstrate that most patients clinically diagnosed with primary FS had undiagnosed systemic abnormalities and/or intra-articular pathologies. Therefore, a modification of the Zuckerman and Rokito's classification system for FS may be required to include the frequent combinations, rather than having a separate representation of systemic abnormalities and intrinsic causes.

• Journal of Korean Neurosurgical Society
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• v.58 no.4
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• pp.379-384
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• 2015

Objective : To investigate the risks and pattern of evolution of peritumoral brain edema (PTE) after stereotactic radiosurgery (SRS) for asymptomatic intracranial meningiomas. Methods : A retrospective study was conducted on 320 patients (median age 56 years, range 24-87 years) who underwent primary Gamma Knife radiosurgery for asymptomatic meningiomas between 1998 and 2012. The median tumor volume was 2.7 cc (range 0.2-10.5 cc) and the median follow-up was 48 months (range 24-168 months). Volumetric data sets for tumors and PTE on serial MRIs were analyzed. The edema index (EI) was defined as the ratio of the volume of PTE including tumor to the tumor volume, and the relative edema indices (rEIs) were calculated from serial EIs normalized against the baseline EI. Risk factors for PTE were analyzed using logistic regression. Results : Newly developed or increased PTE was noted in 49 patients (15.3%), among whom it was symptomatic in 28 patients (8.8%). Tumor volume larger than 4.2 cc (p<0.001), hemispheric tumor location (p=0.005), and pre-treatment PTE (p<0.001) were associated with an increased risk of PTE. rEI reached its maximum value at 11 months after SRS and decreased thereafter, and symptoms resolved within 24 months in most patients (85.7%). Conclusion : Caution should be exercised in decision-making on SRS for asymptomatic meningiomas of large volume (>4.2 cc), of hemispheric location, or with pre-treatment PTE. PTE usually develops within months, reaches its maximum degree until a year, and resolves within 2 years after SRS.

• Journal of Korean Neurosurgical Society
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• v.37 no.1
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• pp.20-24
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• 2005

Objective: The purpose of this study is to assess the efficacy and advantages of an endoscopic endonasal approach for the treatment of pituitary tumors. Methods: We retrospectively analyzed the records of 31 patients with pituitary tumors having endoscopic endonasal surgery between March 1999 and August 2003. Results: Among 31 patients with pituitary adenomas, 25 (81%) patients exhibited gross total removal of tumor on postoperative MRI within 3 days after surgery. Among 6 patients removed subtotally, 2 had only radiosurgery, 3 have had periodic follow-up MRIs and one patient with large extended tumor (grade IV, Stage E) had secondary transcranial removal of tumor before radiosurgery. Postoperative complications included cerebrospinal fluid leak in 2 patients, sinusitis in 1 patient, and one patient died due to unexpected intracerebral hemorrhage on 5 days after surgery. Besides considerable experiences with this approach are needed because of narrow working channel to the sella turcica, the results of our study showed following advantages of this procedure: visualization of areas not seen with the operating microscope, elimination of oronasal complications, more functional and cosmetic outcome, and shortened operative time and hospital stay. Conclusion: The authors consider that endoscopic endonasal transsphenoidal approach provides good results with minimal invasion for patients with pituitary tumors.

• Journal of Korean Neurosurgical Society
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• v.54 no.1
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• pp.34-37
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• 2013

Objective : The purposes of this study were to evaluate the prevalence, types, and locations of Modic changes (MCs) in the thoracic spine in a large number of subjects, and to investigate the relation between the distributions of MCs and disc herniations (DHs) in the thoracic spine. Methods : Two experienced musculoskeletal radiologists assessed the presence of MCs and DHs by consensus in the thoracic MRIs of 144 patients with non-specific back pain. Patient ages ranged from 22 to 88 years (mean=$53.3{\pm}14.66$ years), and 72 were female (50%). The prevalence, distribution, relation of MCs and DHs was recorded. Results : MC was observed in 8 of the 144 patients (5.6%) and 10 of 1728 segments (0.58%). The most common MC was type II. Of the 8 patients exhibiting MC, 6 had type II (75.0%), and 2 had mixed MCs (type I/II or type II/III). MCs were distributed mainly at the mid-thoracic level (from T5/6 to T9/10). DH was detected in 18 patients (12.5%), 36 of 1728 segments (2.1%). Of the 10 segments exhibiting MC, 5 had DHs at the same level (50.0%). Accordingly, DH was strongly associated with MC (p=0.000). Conclusion : A low prevalence of MC was observed in the thoracic spine, and type II MC predominated. The low prevalence of MC in the thoracic spine suggests that it was caused by a relative lack of mobility as compared with the cervical and lumbar spines. And DHs were found to be strongly associated with MCs even in the thoracic spine.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.5179-5196
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• 2019

To explore an effective non-invasion medical imaging diagnostics approach for hepatocellular carcinoma (HCC), we propose a method based on adopting the multiple technologies with the multi-parametric data fusion, transfer learning, and multi-scale deep feature extraction. Firstly, to make full use of complementary and enhancing the contribution of different modalities viz. multi-parametric MRI images in the lesion diagnosis, we propose a data-level fusion strategy. Secondly, based on the fusion data as the input, the multi-scale residual neural network with SPP (Spatial Pyramid Pooling) is utilized for the discriminative feature representation learning. Thirdly, to mitigate the impact of the lack of training samples, we do the pre-training of the proposed multi-scale residual neural network model on the natural image dataset and the fine-tuning with the chosen multi-parametric MRI images as complementary data. The comparative experiment results on the dataset from the clinical cases show that our proposed approach by employing the multiple strategies achieves the highest accuracy of 0.847±0.023 in the classification problem on the HCC differentiation. In the problem of discriminating the HCC lesion from the non-tumor area, we achieve a good performance with accuracy, sensitivity, specificity and AUC (area under the ROC curve) being 0.981±0.002, 0.981±0.002, 0.991±0.007 and 0.999±0.0008, respectively.

• Imaging Science in Dentistry
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• v.31 no.2
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• pp.73-84
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• 2001

Purpose: The purpose of this study was to find the relationship among the joint status, pain and effusion in patients with temporomandibular joint disorders. Materials and Methods: Materials included 406 patients (812 joints) with clinical records and bilateral TMJ MRIs in TMJ clinic, Yongdong Severance Hospital. All joints were classified in 4 groups in MR images according to the disc status of joint; normal disc position, disc displacement with reduction (DDcR), early and late stage of disc displacement without reduction (DDsR), and also 2 groups according to the bony status of joint; normal bony structure and osteoarthrosis. MR evidence of joint effusion was categorized in 4 groups according to its amount. To determine the relationship between joint pain and joint effusion, 289 patients with unilateral TMJ symptoms were selected from total materials. Result: Joint effusion was found 8.0% in normal disc position, 32.6% in DDcR, and 59.2% in DDsR (83.1 % in early state and 23.1 % in late stage). Joint effusion was found 39.7% in osteoarthrosis and 35.0% in normal bony structure. Joint effusion was more found in the painful joints (49.8%) than in the painless joints (22.4% )(p<0.001). Joint effusion in the early stage of DDsR only was more found significantly in painful joints (91.9%) than in painless joints (62.1 %) (p<0.001). Conclusion : MR evidence of joint effusion might be related to disc displacement regardless of the presence of osteoarthrosis, and the early stage of DDsR was found more frequently combined with joint effusion and joint pain.