• Investigative Magnetic Resonance Imaging
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• v.9 no.1
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• pp.50-56
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• 2005

Contrast extravasation in hyperacute intracerebral hemorrhage (ICH) indicative of active bleeding is a predictor of possible enlargement of hematoma, providing clinician with valid management decisions. We report unusual MR imaging features of contrast extravasation in hyperacute ICH in three patients: Case 1 with hypertension revealed dual foci of contrast extravasation, one in right basal ganglia and the other in left lateral ventricle, suggesting simultaneous bleeding of the two foci. Case 2 with presumed diagnosis of vasculitis showed relatively large area of contrast extravasation mimicking enhancing tumor or vascular lesion. Case 3 with hypertension showed the findings of active bleeding which was likely to occur during the time of MR imaging acquisition.

• Investigative Magnetic Resonance Imaging
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• v.17 no.4
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• pp.321-325
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• 2013

Metastases from hepatocellular carcinoma (HCC) can be found in the multiple organs including adrenal gland. But adrenal metastasis of HCC without obvious hepatic lesion is very rare. We report CT and MR findings of a patient who presented with adrenal metastasis as the first clinical manifestation of HCC. Signal intensity and enhancement pattern of adrenal metastastic mass of HCC were similar to those of HCC on MRI.

• Journal of the Korean Society of Radiology
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• v.82 no.5
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• pp.1163-1185
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• 2021

Sudden cardiac death is an unexpected death originating from the heart that occurs within an hour of the onset of symptoms. The main cause of sudden cardiac death is arrhythmia; however, diagnosing underlying structural heart disease significantly contributes to predicting the long-term risk. Cardiovascular CT and MR provide important information for diagnosing and evaluating structural heart disease, enabling the prediction and preparation of the risk of sudden cardiac death. Therefore, we would like to focus on the various structural heart diseases that increase the risk of clinically-important sudden cardiac death and the importance of imaging findings.

• Journal of Yeungnam Medical Science
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• v.18 no.1
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• pp.30-38
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• 2001

Background: The purpose of this study was to evaluate the usefulness of diffusion-weighted magnetic resonance imaging for monitoring the response to radiation therapy in metastatic bone marrow of the spines. Materials and Methods: Twenty-one patients with metastatic bone marrow of the spines were examined with MRI. Diffusion-weighted and spin-echo MRI were performed in 10 patients before and after radiation therapy with or without systemic chemotherapy, and performed in 11 patients after radiation therapy alone. Follow up spin-echo and diffusion-weighted MRI were obtained at 1 to 6 months after radiation therapy according to patients' condition. The diffusion-weighted imaging sequence was based on reversed fast imaging with steady-state precession (PSIF). Signal intensity changes of the metastatic bone marrows before and after radiation therapy on conventional spin-echo sequence MRI and diffusion-weighted MRI were evaluated. Bone marrow contrast ratios and signal-to-noise ratios before and after radiation therapy of diffusion- weighted MRI were analyzed. Results: All metastatic bone marrow of the spinal bodies were hyperintense to normal bone marrow of the spinal bodies on pretreatment diffusion-weighted MRI and positive bone marrow contrast ratios(p<0.001), and hypointense to normal spinal bodies on posttreatment diffusion-weighted MRI and negative bone marrow contrast ratios(p<0.001). The signal to noise ratios after treatment decreased comparing with those of pretreatment. Decreased signal intensity of the metastatic bone marrows on diffusion-weighted MRI began to be observed at average more than one month after the initiation of the radiation therapy. Conclusion: These results suggest that diffusion-weighted MRI would be an excellent method for monitoring the response to therapy of metastatic bone marrow of the spinal bodies, however, must be investigated in a larger series of patients with longer follow up period.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.69-81
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• 2019

We consider bivariate long range dependent (LRD) time series forecasting using a deep learning method. A long short-term memory (LSTM) network well-suited to time series data is applied to forecast bivariate time series; in addition, we compare the forecasting performance with bivariate fractional autoregressive integrated moving average (FARIMA) models. Out-of-sample forecasting errors are compared with various performance measures for functional MRI (fMRI) data and daily realized volatility data. The results show a subtle difference in the predicted values of the FIVARMA model and VARFIMA model. LSTM is computationally demanding due to hyper-parameter selection, but is more stable and the forecasting performance is competitively good to that of parametric long range dependent time series models.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.385-392
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• 2023

Caroli's disease is a fibrocystic liver disease. Autosomal recessive disorder is characterized by congenital multiple dilatation of the bile duct. Computerized tomography, magnetic resonance imaging, cholangiography and ultrasound are among the methods for diagnosing caroli disease. Computerized tomography is essential for detecting and distinguishing fibroplastic liver disease and is useful for determining intrahepatic bile duct dilatation. However, awareness of the possible side effects of using contrast mediums is necessary. A typical method of magnetic resonance cholangiography is used for magnetic resonance imaging. A non-invasive examination can reduce the pain of the patient, and the anatomical structure of the bile pancreatic duct and the presence or absence of lesions can be easily and quickly observed. Biliary contrast is an effective diagnostic method that can directly visualize various cystic dilatations throughout the enlarged bile duct. However, since this procedure is also an invasive procedure, it is recommended not for diagnosis but for treatment purposes. Ultrasonography can confirm similar findings to computerized tomography. The hepatic artery root is difficult to prove with conventional grayscale ultrasound. However, it is of clinical value in that it can not only describe dilated bile ducts with vascular roots in the tube but also easily identify color Doppler signals in the tube. With the development of video diagnostics, early diagnosis has become possible through computerized tomography, magnetic resonance imaging, cholangiography, and ultrasound. In order to further contribute to the development of video diagnostics so that long-term prognosis can be improved after treatment through early diagnosis, we examined what aspects of each test's caroli disease appear.

• 대한관절경학회:학술대회논문집
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• 2009.10a
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• pp.14-22
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• 2009

회전근 개 부분 파열은 노화의 과정 중 생기는 무증상의 병변 또는 견관절 기능 장애의 잠재적인 원인으로 생각되었다. 발병 원인은 해부학적인 원인에 의한 충돌 또는 반복적 미세 외상 등이 원인으로 이해되고 있으며 병리생태에 관한 이해가 깊어지고 진단 기구, 즉 초음파나 자기공명영상, 관절경 등의 발달로 발생률이 과거에 비해 증가하고 있다. 그러나 회전근 개부분 파열은 질환 자체보다 전층 파열로 진행하는 일종의 질환 스펙트럼(disease spectrum)의 개념으로 전층 파열에 비해 현재까지 발표된 연구 자료가 많지 않다. 즉 회전근 개 부종, 견봉과의 마찰로 생긴 염증성 건병증, 회전근 개 섬유화 및 부분 또는 전층 파열로 진행되는 회전근 개 병변의 스펙트럼의 일부로 간주되는 경우가 많다. 본 종설은 회전근 개 부분 파열의 진단, 파열 분류, 수술의 적응증 및 수술 방법과 그 결과에 대해 논하고자 한다.

• Korean Journal of Biological Psychiatry
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• v.4 no.1
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• pp.60-66
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• 1997

Objective : Accumulating evidence suggests a greater number of subcortical hyperintensities in the brain of patients with bipolar disorder. We studied the Clinical correlates of subcortical hyperintensities on magnetic resonance imaging in patients with Bipolar Disorder : Methods : Magnetic resonance images of the brain were obtained for 32 patients with bipolar disorder. The presence and location of hyperintensities were assessed. We compared clinical variables between patients with subcortical hyperintensities and patients without them. Results : Seven patients(21.8%) had subcortical hyperintensities, but among 8 patients who were 40 years or older, 5 patients(62%) had them. Age and age at onset of patients with subcortical hyperintensities were significantly older than patients without them. Psychotic symptoms were more frequent in patients with hyperintensities. Patients without hyperintensities had more familial loadings. Conclusion : Given the limitations of the study, our results should be seen as preliminary. This study, however, provides preliminary evidence supporting the notion that the onset, clinical feature and course of some bipolar disorders of late onset may be determined by underlying subcortical abnormalities, with such abnormalities being the consequence of factors related to aging or neurodegeneration(such as impaired cerebral circulation) rather than genetic factors which predispose to early-onset bipolar disorders.

• Journal of the Korean Society of Radiology
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• v.84 no.3
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• pp.686-691
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• 2023

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a fibroinflammatory disorder that can involve any organ system; however, myocarditis is extremely rare. A 52-year-old male with dyspnea and chest discomfort underwent cardiac MRI that revealed edema and nodular, patchy, mesocardial and subendoardial delayed enhancement of left ventricle, suggesting myocarditis. Laboratory findings revealed elevated serum IgG4 and eosinophilia. Cardiac biopsy confirmed eosinophilic myocarditis with IgG4-positive cells. Here, we present an unusual case of IgG4-RD manifesting as eosinophilic myocarditis.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.119-124
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• 1997

Purpose: To assess the utility of magnetic resonance(MR) cerebral blood volume (CBV) map in the evaluation of brain tumors. Materials and Methods: We performed perfusion MR imaing preoperatively in the consecutive IS patients with intracranial masses(3 meningiomas, 2 glioblastoma multiformes, 3 low grade gliomas, 1 lymphoma, 1 germinoma, 1 neurocytoma, 1 metastasis, 2 abscesses, 1 radionecrosis). The average age of the patients was 42 years (22yr -68yr), composed of 10 males and S females. All MR images were obtained at l.ST imager(Signa, CE Medical Systems, Milwaukee, Wisconsin). The regional CBV map was obtained on the theoretical basis of susceptibility difference induced by first pass circulation of contrast media. (contrast media: IScc of gadopentate dimeglumine, about 2ml/sec by hand, starting at 10 second after first baseline scan). For each patient, a total of 480 images (6 slices, 80 images/slice in 160 sec) were obtained by using gradient echo(CE) single shot echo-planar image(EPI) sequence (TR 2000ms, TE SOms, flip angle $90^{\circ}$, FOV $240{\times}240mm,{\;}matrix{\;}128{\times}128$, slice-thick/gap S/2.S). After data collection, the raw data were transferred to CE workstation and rCBV maps were generated from the numerical integration of ${\Delta}R2^{*} on a voxel by voxel basis, with home made software (${\Delta}R2^{*}=-ln (S/SO)/TE). For easy visual interpretation, relative RCB color coding with reference to the normal white matter was applied and color rCBV maps were obtained. The findings of perfusion MR image were retrospectively correlated with Cd-enhanced images with focus on the degree and extent of perfusion and contrast enhancement. Results: Two cases of glioblastoma multiforme with rim enhancement on Cd-enhanced Tl weighted image showed increased perfusion in the peripheral rim and decreased perfusion in the central necrosis portion. The low grade gliomas appeared as a low perfusion area with poorly defined margin. In 2 cases of brain abscess, the degree of perfusion was similar to that of the normal white matter in the peripheral enhancing rim and was low in the central portion. All meningiomas showed diffuse homogeneous increased perfusion of moderate or high degree. One each of lymphoma and germinoma showed homogenously decreased perfusion with well defined margin. The central neurocytoma showed multifocal increased perfusion areas of moderate or high degree. A few nodules of the multiple metastasis showed increased perfusion of moderate degree. One radionecrosis revealed multiple foci of increased perfusion within the area of decreased perfusion. Conclusion: The rCBV map appears to correlate well with the perfusion state of brain tumor, and may be helpful in discrimination between low grade and high grade gliomas. The further study is needed to clarify the role of perfusion MR image in the evaluation of brain tumor.