• Radiation Oncology Journal
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• v.30 no.4
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• pp.173-181
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• 2012

Purpose: To evaluate the prognostic value of preoperative neck lymph node (LN) assessment with $^{18}F$-fluorodeoxyglucose positron emission tomography ($^{18}F$-FDG PET), computed tomography (CT), and magnetic resonance imaging (MRI) in oral cavity squamous cell carcinoma (OSCC) patients with pathologically positive LN. Materials and Methods: In total, 47 OSCC patients with pathologically positive LN were retrospectively reviewed with preoperative $^{18}F$-FDG PET and CT/MRI. All patients underwent surgical resection, neck dissection and postoperative adjuvant radiotherapy and/or chemotherapy between March 2002 and October 2010. Histologic correlation was performed for findings of $^{18}F$-FDG PET and CT/MRI. Results: Thirty-six (76.6%) of 47 cases were correctly diagnosed with neck LN metastasis by $^{18}F$-FDG PET and 32 (68.1%) of 47 cases were correctly diagnosed by CT/MRI. Follow-up ranged from 20 to 114 months (median, 56 months). Clinically negative nodal status evaluated by $^{18}F$-FDG PET or CT/MRI revealed a trend toward better clinical outcomes in terms of overall survival, disease-free survival, local recurrence-free survival, regional nodal recurrence-free survival, and distant metastasis-free survival rates even though the trends were not statistically significant. However, there was no impact of neck node standardized uptake value ($SUV_{max}$) on clinical outcomes. Notably, $SUV_{max}$ showed significant correlation with tumor size in LN (p < 0.01, $R^2$ = 0.62). PET and CT/MRI status of LN also had significant correlation with the size of intranodal tumor deposit (p < 0.05, $R^2$ = 0.37 and p < 0.01, $R^2$ = 0.48, respectively). Conclusion: $^{18}F$-FDG PET and CT/MRI at the neck LNs might improve risk stratification in OSCC patients with pathologically positive neck LN in this study, even without significant prognostic value of $SUV_{max}$.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.100-100
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• 2002

목적： 인체에 전류를 주입하면 체내 생체조직의 임피던스 분포에 따라서 전류밀도 분포가 결정된다. 이러한 전류밀도 분포를 MRI를 이용하여 고해상도로 얻어내면 인체 내부의 임피던스 영상을 구성할 수 있다. 이는 기존의 전기 임피던스 단층 촬영법이 갖는 여러 한계를 극복할 수 있으며 이로부터 생체의 기능에 대한 다양한 정보를 추출할 수 있게 된다. 본 논문은 3차원 팬텀 내부의 전류밀도 분포를 영상화하고 이것으로부터 인체내부의 임피던스 영상을 얻어내는 실험 결과를 기술한다.

• Korean Journal of Digital Imaging in Medicine
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• v.3 no.1
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• pp.110-118
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• 1997

Recently, to make a diagnosis of the patient different X-Ray examinations are used. To name a few, Computed Tomography(CT). Magnetic Resonance Image(MRI) Single Photon Emission Computed Tomography(SPET) and Positron Emission Tomography(PET). But diagnosticians face difficulties sometimes when they make a diagnosis with images from those examinations. One of the problem is whether the Lesions of the patient is captured in the image correctly. Another one is whether the images are taken with same angle. in this paper, a study 9 on the method to obtain the hybrid image from the different images to different examinations. The procedure done in this paper is described as future study. Although small errors in position between images would occurred, this method more useful as it does not make patients in convenient. To reconstruct a image, some images are scanned by scanner and stored to personal computer for further image processing with Aldus photostyler program. The method to generate a sharpened image are also described.

• Annals of Clinical Neurophysiology
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• v.10 no.1
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• pp.13-24
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• 2008

Functional neuroimaging, especially positron emission tomography (PET) and functional magnetic resonance imaging (MRI), is the main tool that allows the unveiling of the neurovascular events during a migraine attack. In migraine with aura, functional neuroimaging has contributed greatly to the understanding of the fundamental pathophysiology of the visual aura, whereas in migraine without aura, the PET findings of brainstem activation suggest a pivotal role of brainstem in the generation of migraine headache. In addition, voxel-based morphometry (VBM) method has provided an insight into the morphometric changes of the brain, which might be considered as a consequence of repeated migraine attacks. In this article, I will briefly discuss the main neuroimaging findings pertaining to the pathophysiology of migraine.

• Journal of Korean Neurosurgical Society
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• v.60 no.1
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• pp.98-101
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• 2017

We report a case of primary intracranial malignant melanoma (PIMM) with extracranial metastases. The patient was an 82-year-old woman diagnosed with PIMM under the left cerebellar tentorium. We performed a tumor resection followed by gamma knife surgery. An magnetic resonance imaging at 11 months after surgery showed a local intracranial recurrence. At 12 months, vertebral metastasis was suspected, and 2-[fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) showed multiple extracranial metastases. She died at 13 months after surgery. Although extracranial metastases of PIMM are extremely rare, we should carefully follow up extracranial metastases together with intracranial ones, especially by FDG-PET/CT, even at an early asymptomatic stage.

• Journal of information and communication convergence engineering
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• v.8 no.2
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• pp.205-211
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• 2010

In this study, a Magnetic stimulation Pulse Train control technique is introduced and applied to Flyback converter operating in discontinuous conduction mode. In contrast to the conventional pulse width modulation control scheme, the principal idea of a Magnetic stimulation Pulse Train is to achieve output voltage regulation using high and low power pulses. The proposed technique is applicable to any converter operating in discontinuous conduction. However, this work mainly focuses on Flyback topology. In this paper, the main mathematical concept of the new control algorithm is introduced and simulations as well as experimental results are presented.

• Investigative Magnetic Resonance Imaging
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• v.19 no.1
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• pp.47-51
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• 2015

Sarcomatous Intrahepatic cholangiocarcinoma is a rare but an aggressive variant of cholangiocarcinoma with a very poor prognosis. A 79-year-old man was admitted to our hospital because of incidentally found liver mass. Magnetic resonance imaging (MRI) revealed well-defined hypointense mass on T1WI and heterogeneous hyperintense mass on T2WI. Gd-EOB-DTPA enhanced study shows peripheral rim-like enhancement in arterial phase and progressive concentric filling of contrast in delayed phase. And mass shows significant enhancement in hepatobiliary phase. The pathologic diagnosis was intrahepatic cholangiocarcinoma with sarcomatous change.

• Journal of Biomedical Engineering Research
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• v.25 no.3
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• pp.165-169
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• 2004

In Magnetic Resonance Electrical Impedance Tomography (MREIT), we inject current through electrodes placed on the surface of a subject and measure the induced magnetic flux density distribution using an MRI scanner. This requires a constant current source whose output pulses are synchronized with MR pulse sequences. In this paper, we present a design and performance analysis of a current source used in a 3.0T MREIT system. The developed current source was tested using a saline phantom. We found that its performance is satisfactory for the current MREIT system. We suggest future improvements for better SNR(signal-to-noise ratio).

• Investigative Magnetic Resonance Imaging
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• v.11 no.2
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• pp.119-126
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• 2007

MR (magnetic resonance) imaging of the brachial plexus is challenging because of the complex and tangled anatomy of the brachial plexus and the multifariouness of pathologies that can put on it. Improvements in imaging techniques, including the availability of high resolution MR image systems and high channels multidetector computed tomography (CT), have led to more accurate diagnoses and improved serve for treatment planning. For the purpose of imaging and treatment of the brachioplexopathy, it is considerate to divide traumatic and nontraumatic diseases affecting the brachial plexus. MRI is the current gold standard imaging modality for nontraumatic brachial plexopathy. CT myelography is the preferred for the diagnosis of nerve root avulsions affecting the brachial plexus. Other modalities, such as CT, ultrasonography and positron emission tomography, have a limited role in the evaluation of brachial plexus pathology. High-quality, high-resolution MRI remains the main tool for imaging the brachial plexopathy.

• Journal of Korean Neurosurgical Society
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• v.56 no.6
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• pp.504-508
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• 2014

A 59-year-old male patient had 5-month history of gait disturbance and memory impairment. His initial brain computed tomography scan showed $3.5{\times}2.8cm$ sized mass with high density in the pineal region. The tumor was hypointense on T2 weighted magnetic resonance images and hyperintense on T1 weighted magnetic resonance images with heterogenous enhancement of central portion. The tumor was totally removed via the occipital transtentorial approach. Black mass was observed in the operation field, and after surgery, histopathological examination confirmed the diagnosis of malignant melanoma. Whole spine magnetic resonance images and whole body 18-fluoro-deoxyglucose positron emission tomography could not demonstrate the primary site of this melanoma. Scrupulous physical examination of his skin and mucosa was done and dark pigmented lesion on his left leg was found, but additional studies including magnetic resonance images and skin biopsy showed negative finding. As a result, final diagnosis of primary pineal malignant melanoma was made. He underwent treatment with the whole brain radiotherapy and extended local boost irradiation without chemotherapy. His preoperative symptoms were disappeared, and no other specific neurological deficits were founded. His follow-up image studies showed no recurrence or distant metastasis until 26 weeks after surgery. Primary pineal malignant melanomas are extremely rare intracranial tumors, and only 17 cases have been reported since 1899. The most recent case report showed favorable outcome by subtotal tumor resection followed by whole brain and extended local irradiation without chemotherapy. Our case is another result to prove that total tumor resection with radiotherapy can be the current optimal treatment for primary malignant melanoma in the pineal region.