• Korean Journal of Radiology
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• 제20권5호
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• pp.801-811
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• 2019

Objective: To determine whether diffusion kurtosis imaging (DKI) is effective in monitoring tumor response to neoadjuvant chemotherapy in patients with osteosarcoma. Materials and Methods: Twenty-nine osteosarcoma patients (20 men and 9 women; mean age, 17.6 ± 7.8 years) who had undergone magnetic resonance imaging (MRI) and DKI before and after neoadjuvant chemotherapy were included. Tumor volume, apparent diffusion coefficient (ADC), mean diffusivity (MD), mean kurtosis (MK), and change ratio (ΔX) between pre-and post-treatment were calculated. Based on histologic response, the patients were divided into those with good response (≥ 90% necrosis, n = 12) and those with poor response (< 90% necrosis, n = 17). Several MRI parameters between the groups were compared using Student's t test. The correlation between image indexes and tumor necrosis was determined using Pearson's correlation, and diagnostic performance was compared using receiver operating characteristic curves. Results: In good responders, MD_post, ADC_post, and MK_post values were significantly higher than in poor responders (p < 0.001, p < 0.001, and p = 0.042, respectively). The ΔMD and ΔADC were also significantly higher in good responders than in poor responders (p < 0.001 and p = 0.01, respectively). However, no significant difference was observed in ΔMK (p = 0.092). MD_post and ΔMD showed high correlations with tumor necrosis rate (r = 0.669 and r = 0.622, respectively), and MD_post had higher diagnostic performance than ADC_post (p = 0.037) and MK_post (p = 0.011). Similarly, ΔMD also showed higher diagnostic performance than ΔADC (p = 0.033) and ΔMK (p = 0.037). Conclusion: MD is a promising biomarker for monitoring tumor response to preoperative chemotherapy in patients with osteosarcoma.

• Nuclear Medicine and Molecular Imaging
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• 제42권1호
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• pp.79-80
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• 2008

Including malignancy, various disease can show abnormal uptake in bone marrow. We report a case of non-specific inflammatory FDG uptake in bone marrow mimicking malignancy. A 35-year old woman with fever of unknown origin (FUO) underwent $^{18}F$-FDG PET/CT to find out fever $^{18}F$-FDG and unknown malignancy. $^{18}F$-FDG was injected and imaged 1hr after injection with Discovery ST (GE, USA), $^{18}F$-FDG PET/CT whole body image showed abnormal uptake in lower extremities (Fig. 1). MRI and biopsy was also done in the sites of abnormal uptake. PET and MRI suspect malignancy (Fig. 2, 3), but biopsy result was non-specific inflammatory process (Fig. 4). The patient was improved her clinical condition after antibiotics therapy.

• Clinical and Experimental Pediatrics
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• 제53권7호
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• pp.759-765
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• 2010

Purpose: This study evaluated the clinical manifestations of and risk factors for pituitary insufficiency in children and adolescents with Rathke's cleft cysts. Methods: Forty-four patients with Rathke's cleft cysts younger than 19 years who visited Seoul National University Children's Hospital between January 1995 and September 2009 were enrolled. Rathke's cleft cysts were confirmed histologically through an operation in 15 patients and by brain magnetic resonance imaging (MRI) in 29 patients. The clinical, hormonal, and imaging features were reviewed retrospectively. Results: The clinical presentation of symptomatic patients was as follows: headache (65%), endocrinopathy (61%), and visual disturbance (19%). Endocrinopathy included central precocious puberty (18%), diabetes insipidus (14%), general weakness (11%), and decreased growth velocity (7%). After surgery, hyperprolactinemia resolved in all patients, but growth hormone insufficiency, hypothyroidism, and diabetes insipidus did not improve. Pituitary insufficiency except gonadotropin abnormality correlated significantly with severe headache, visual disturbance, general weakness, and cystic size. Suprasellar extension of cysts and high signals in the T2-weighted image on brain MRI were related to hypothyroidism, hypocortisolism, and diabetes insipidus. Multivariable linear regression analysis showed that only general weakness was a risk factor for pituitary insufficiency ($R^2$=0.549). Conclusion: General weakness is a risk factor for pituitary insufficiency in patients with Rathke's cleft cysts. When a patient with a Rathke's cleft cyst complains of general weakness, the clinician should evaluate pituitary function and consider surgical treatment.

• Investigative Magnetic Resonance Imaging
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• 제21권3호
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• pp.187-191
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• 2017

Bone marrow aspirates concentrate (BMAC) transplantation is a well-known technique for cartilage regeneration with good clinical outcomes for symptoms in patients with osteoarthritis (OA). Magnetic resonance imaging (MRI) has an important role in evaluating the degree of cartilage repair in cartilage regeneration therapy instead of a second assessment via an arthroscopy. We experienced a case of hypertrophic regeneration of the cartilage and a presumed simultaneous regeneration of the posterior horn of the lateral meniscus after BMAC transplantation for a cartilage defect at the lateral tibial and femoral condyle. This report provides the details of a case of an unusual treatment response after a BMAC transplant. This report is the first of its kind to demonstrate a MR image that displays the simultaneous regeneration of the cartilage and meniscus with a differentiation ability of the mesenchymal stem cell to the desired cell lineage.

• 한국통신학회논문지
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• 제34권7C호
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• pp.671-680
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• 2009

진단용 디지털 의료영상(CT, MRI)의 경우 일반 영상에 비해 막대한 데이터양으로 인하여 저장과 전송에 많은 문제점이 발생한다. 이러한 문제점을 극복하는 간단한 방법은 압축률을 증가시키는 것이다. 그럼에도 불구하고 정확한 진단을 위한 임상적언 판단을 요구한다. 본 논문의 목적은 고주파대역에서 시각적 무손실 임계필터링을 수행하므로써 무손실 JPEG2000의 압축 효율을 향상시키는 것이다. 제안방식은 5/3 가역 DWT(Digital Wavelet Transfrom)을 사용하였을 때 압축률에 따라 다른 부대역 임계값을 사용하며, 재생된 진단 CT 영상에 시각적 무손실의 고품질을 제공한다.

• Imaging Science in Dentistry
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• 제31권3호
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• pp.159-164
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• 2001

Purpose: To evaluate the osseous changes of TMJ in internal derangement and osteoarthritis patients using MRI. Materials and Methods: MR images of 111 TMJs in 64 patients were analyzed to evaluate the osseous changes, 111 TMJs were divided into 6 groups according to the radiologic Stages by Schellhas and Wilkes. On MR images, we evaluate the osseous changes of articular eminence and condylar head. Results: The most frequent Stage in internal derangement of TMJ was Stage I. And 28 joints (25.2%) revealed osteoarthritis with internal derangement. When osseous change of articular eminence and condylar head occur, flattening was the most common osseous change. Sclerosis was observed in all Stages and osteophytosis of condylar head was observed in Stage II (1.8%) and III (0.9%). Out of 28 joints with osteoarthritis, 6 joints (21.4%) showed joint effusion. Conclusion: MR image revealed abnormal configuration of disk, but the detection of minimal osseous change was subtle.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2004년도 제29회 추계학술대회 발표논문집
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• pp.56-58
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• 2004

동물실험을 위한 영상의 개선작업도 인체내 구성물질들과 흡사하고 유동성을 지니고 있으므로 영상의 평가는 기본적으로 일차적 관계의 생화학적 테두리에 있다. 그리고 선구자들이 밝혀준 임상에의 응용에 있어서 아주 작거나 존재하지 않는 것처럼 충분히 작은 미소체적공간으로 가정을 한다. 비선형Marquardt 알고리듬을 응용하여 수학적인 모델링을 도입하고 전개하였다. 본 연구의 목적은 인체와 매우 비슷한 생화학적 구조와 밀도를 가진 동물실험에서 영상을 획득한 후 수학적 모델링을 통한 입체적 체적을 분석하는데 있어서 기준을 제시하고자 한다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2011년도 춘계 종합학술대회 논문집
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• pp.201-202
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• 2011

본 연구에는 7.0T 동물용 자기공명영상장치를 이용하여 인간의 췌장암 세포인 CFPAC-1를 이종 이식한 쥐에서 자기공명영상을 획득하여 최적화된 검사 Protocol을 정립하며, 동물 실험에서 밝혀진 종양특성과 확산강조영상과의 비교 분석을 해보고 현성확산계수 영상이 췌장암 이종이식 모형의 종양 세포 내부 구조에 관하여 어떠한 정보를 제공 할 수 있는지 알아보고자 한다. 13마리의 쥐의 26개의 종양을 전형적으로 주입 후에 2~4주 뒤에 직경이 5~10mm가 되었을 때 imaged 하였으며, pathologic specimenm을 위해 sacrificed 하였다. isofluoran gas anesthesia를 이용하여 동물 마취 하였다. 사용된 장비로는 small-animal MR images (7.0-T)를 (Bruker BioSpin GmbH, Rheinstetten, Germany)이용하여 Fast T2-weighted 와 single-shot EPI DW image를 얻었다. 종양은 H&E 염색과 CD31와 VEGF에 대한 면역조직학 염색을 하여 종양의 cellularity와 microvessel density(MVD), 종양 내 괴사 정도를 평가하였다. CFPAC-1의 현성확산계수값은 $0.7327{\pm}0.1075{\pm}10^{-3}mm2/s$이였으며, 현성확산계수는 종양내 괴사 정도와 연관성을 보였다(R = 0.7417, p = 0.0001) 이처럼 현성확산계수는 종양 내 괴사 정도 등의 현미경적구조변화를 반영하는 대리인자로 사용될 수 있음을 확인하였다.

• Journal of Korean Neurosurgical Society
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• 제40권2호
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• pp.110-113
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• 2006

Surgery and radiotherapy are mainly used for plasma cell neoplasm which constitutes about $1{\sim}2%$ of human malignancy. The authors carried out Fractionated Stereotactic Radiotherapy[FSRT] on the residual tumor after the subtotal removal of Intracranial plasmacytoma. A huge mass lesion was observed on MRI [magnetic resonance image] in the left anterior and middle cranial fossa of a 63-year-old man with left exophthalmus which lasted for a month, and was suspected as a meningioma with strong contrast enhancement. Extramedullary plasmacytoma was diagnosed on histopathological examination. After the surgery, FSRT was also carried out on the residual tumor which invaded the skull base. One-year follow up after FSRT showed contrast enhancement only in the left sphenoid bone on MRI, which indicated significant decrease in the size of the tumor without any abnormal neurologic deficits. We treated intracranial plasmacytoma which invaded left anterior and middle cranial fossa and surrounded cavernous sinus without cranial nerve deficit through subtotal tumor removal and FSRT.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1992년도 춘계학술대회
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• pp.85-91
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• 1992

In MRI, an image contrast can be developed as a result of the susceptibility effect if an object has paramagnetic substances. This is mainly due to the non-uniform phase distribution or linear gradient developed by the magnetic susceptibility within a voxel, which in turn reduces the signal intensity; e.g., spin phases are dephased and thereby cancel each other resulting in a reduced signal. In this paper, a new concept for manipulating the susceptibility effect through the use of tailored RF pulses is proposed. As potential applications of the method, two different types of tailored RF pulses are introduced: one for susceptibility artifact correction and the other for contrast enhancement. The latter, for example, can be applied to angiography utilizing the paramagnetic property of deoxygenated blood. Both a theoretical study of the method and experimental results are reported.