• 전자공학회논문지
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• 제53권12호
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• pp.131-138
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• 2016

본 연구에서는 CT에서 사용되는 요오드화 조영제가 가돌리늄조영제와 비교하여 MR영상신호에 어떠한 영향을 미치는지 알아보고자 하였으며, 이에 따른 CT조영증강 검사 이후 MRI검사를 시행하는 프로토콜이 적정한지에 대하여 논하고자 하였다. 실험은 iodine과 gadolinium의 두 개의 팬텀을 제작하여 MRI에서의 통상적인 T1, T2, T2 FLAIR, 3D Angio 검사를 시행 후, 이에 대한 정량적 분석이 이루어졌다. 실험결과 체내 자유수(Free water)와 유사한 셀라인의 신호강도 SSI(Saline's Signal Intensity)는 iodine팬텀에서 각 175, 1231, 333, 37 [a.u]을 보였고, gadolinium팬텀에서 101, 1021, 321, 31 [a.u]을 기록하였다. 셀라인의 SI(Signal Intensity)를 기준으로 가장 큰 차이의 신호강도 BDEPS(the Biggest Difference of EPS)는 iodine팬텀에서 각 1297, 123, 757, 232 [a.u]를 보였고, gadolinium팬텀에서 793, 6, 1495, 365 [a.u]를 기록하였다. 이때 셀라인과 비교한 신호증강정도 EPS(Enhancement Percentage to Saline)는 iodine팬텀에서 641.1 -90.0, 127.3, 527%를 보였고, gadolinium팬텀에서 685.1, 99.4, 365.7, 1077.4% 기록하였다. BDEPS를 보이는 지점인 BP(BDEPS's point)는 iodine팬텀에서 900, 900, 477, 900 mmol을 보였고, gadolinium팬텀에서 4, 0.2, 0.2, 40 mmol을 기록하였다. 셀라인과 비교 하여 육안으로 SI변화를 확인할 수 있는 지점 CPSS(Change Point of SI to SSI)는 iodine팬텀에서 63, 423, 63, 29 mmol을 보였고, gadolinium팬텀에서 각 [50, 30], [4, 0.2], [4, 1], 0.2 mmol을 기록하였다. 본 연구를 통하여 iodine 역시 MR신호에 영향을 끼치며, 이는 gadolinium과는 다른 패턴을 보이는 것을 확인하였다. 이에 따라 임상현장에서 본 연구의 정량화 데이터를 감안하여 CT와 MRI 검사 순서 프로토콜을 결정한다면 유용한 진단학적 MR영상을 구현 할 수 있을 것으로 사료된다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.307-308
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• 1998

In this paper, we describe a field measurement technique using multiple gradient echo method. For this purpose, 3 differential phase map is used between two images obtained in a single scan. The phase map is further processed to unfold phase folding (2n $\pi$). The inhomogeneity map is used to correct image distortion along readout gradient direction. Some experimental results obtained at 1.0 Tesla whole body MR system are shown with the proposed technique.

• 대한두경부종양학회지
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• 제15권2호
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• pp.166-171
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• 1999

Background and Objectives: The aim of our study was to describe the appearance of recurrent and residual lesions in the head and neck tumors, and to evaluate the usefullness of CT and MRI. Materials and Methods: CT(n=42) and MRI(n=4) of 44 patients with recurrent head and neck tumors were reviewed retrospectively. Primary tumor sites were larynx/hypopharynx in 15, oral cavity/floor of mouth in 13, base of tongue/tonsil in 5, nasopharynx in 4, palate in 2, and others in 5 patients. Therapeutic modalities included sugery and radiotherapy in 23, radiotherapy in 11, surgery in 5, chemotherapy and radiotherapy in 4, and chemotherapy in 1 patient. Results: The patterns of tumor recurrence were nodal recurrence(n=17), primary tumor bed recurrence combined with nodal recurrence(n=12), primary tumor bed recurrence(n=10) and residual primary tumors(n=5). The most common appearance of residual/recurrent primary tumor on CT was focal or diffuse heterogenous mass with or without surrounding fat or muscle infiltration(25/27). On MRI, the recurrent lesions showed intermediate signal intensity on T1 weighted image and high signal intensity on T2 weighted image with heterogenous enhancement in the most cases(n=3). 38 out of 44 nodal recurrences(86%) which had been pathologically or clinically proved were more than 1 cm in diameter or contained central low density on CT scan. Conclusion: Although CT and MRI findings of recurrent and residual tumors of the head and neck were nonspecific, in the majority the lesions manifested as a mass at primary tumor bed and/or nodal disease including contralateral side of the neck. And CT and MRI are valuable for revealing above lesions.

• 스마트미디어저널
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• 제9권2호
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• pp.22-32
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• 2020

The hippocampal volume atrophy is known to be linked with neuro-degenerative disorders and it is also one of the most important early biomarkers for Alzheimer's disease detection. The measurements of hippocampal pure volumes from Magnetic Resonance Imaging (MRI) is a crucial task and state-of-the-art methods require a large amount of time. In addition, the structural brain development is investigated using MRI data, where brain morphometry (e.g. cortical thickness, volume, surface area etc.) study is one of the significant parts of the analysis. In this study, we have proposed a patch-based ensemble model of 3-D convolutional neural network (CNN) to measure the hippocampal pure volume from MRI data. The 3-D patches were extracted from the volumetric MRI scans to train the proposed 3-D CNN models. The trained models are used to construct the ensemble 3-D CNN model and the aggregated model predicts the pure volume in one-step in the test phase. Our approach takes only 5 seconds to estimate the volumes from an MRI scan. The average errors for the proposed ensemble 3-D CNN model are 11.7±8.8 (error%±STD) and 12.5±12.8 (error%±STD) for the left and right hippocampi of 65 test MRI scans, respectively. The quantitative study on the predicted volumes over the ground truth volumes shows that the proposed approach can be used as a proxy.

• 대한기관식도과학회지
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• 제6권1호
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• pp.7-15
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• 2000

Background and Objectives:Submucosal spread of hypopharyngeal canceris frequently incriminated for the high incidence of local recurrence after resection. Although mucosal spread is better detected by means of direct visualization, submucosal spread is better evaluated by using cross-sectional imaging rather than endoscopy. This study was designed to evaluate the efficacy of MRI in diagnosing involvement of inferior margin of hypopharyngeal cancer. Materials and Method : Eight patients with hypopharyngeal cancer underwent MRI prior to surgery. And postoperative histopathopogic involvement of tumor was compared with the preoperative MRI axial scan. Results : In preoperative MRI findings, involvement of pyriform sinus apex was 6 cases(definitive 5 cases, probable 1 cases), that of esophageal inlet was 1 case(probable), that of cervical esophagus was 1 case(probable). In postoperative histopathologic findings, the results were same. Conclusion : MRI evaluation for patient with hypopharyngeal cancer ensures accurate staging and provides essential information about the tumor involvement of inferior margin. And there is needed to be thin section thickness in evaluation of inferior margin of hypopharyngeal cancer.

• Korean Journal of Radiology
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• 제23권1호
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• pp.60-67
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• 2022

Objective: To categorize multiparametric MRI features of Bacillus Calmette-Guérin (BCG)-related granulomatous prostatitis (GP) and discover potential manifestations for its differential diagnosis from prostate cancer. Materials and Methods: The cases of BCG-related GP in 24 male (mean age ± standard deviation, 66.0 ± 9.4 years; range, 50-88 years) pathologically confirmed between January 2011 and April 2019 were retrospectively reviewed. All patients underwent intravesical BCG therapy followed by a MRI scan. Additional follow-up MRI scans, including diffusion-weighted imaging (DWI), were performed in 19 patients. The BCG-related GP cases were categorized into three: A, B, or C. The lesions with diffusion restriction and homogeneous enhancement were classified as type A. The lesions with diffusion restriction and a poorly enhancing component were classified as type B. A low signal intensity on high b-value DWI (b = 1000 s/mm²) was considered characteristic of type C. Two radiologists independently interpreted the MRI scans before making a consensus about the types. Results: The median lesion size was 22 mm with the interquartile range (IQR) of 18-26 mm as measured using the initial MRI scans. The lesion types were A, B, and C in 7, 15, and 2 patients, respectively. Cohen's kappa value for the inter-reader agreement for the interpretation of the lesion types was 0.837. On the last follow-up MRI scans of 19 patients, the size decreased (median, 5.8 mm; IQR, 3.4-8.5 mm), and the type changed from A or B to C in 11 patients. The lesions resolved in four patients. In five patients who underwent prostatectomy, caseous necrosis on histopathology matched with the non-enhancing components of type B lesions and the entire type C lesions. Conclusion: BCG-related GP demonstrated three imaging patterns on multiparametric MRI. Contrast-enhanced T1-weighted imaging and DWI may play a role in its differential diagnosis from prostate cancer.

• 대한한방내과학회지
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• 제22권4호
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• pp.729-733
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• 2001

We report a case of the cerebellar infarction and pons, medulla and mid brain infarction seen in a 30-year-old female with systemic lupus erythematosus(SLE). SLE has been diagnosed at 1992, and treated with western medicine for 10 years. The patient with right hand tremor and dysarthria, as the symptoms of a cerebellar infarction, visited our hospital. During treatment, the patient constantly complained left knee pain, it turned out the bone infarction and ligament injury in the MRI scan at May, 18, 2001, that was the side effect of the long period steroid therapy. At June 1, 2001, the patient revealed quadriparesis, dysphagia and dizziness. So we took the brain MRI scan, it showed pons, medulla and mid brain infarction. As the consequence of the oriental treatments, the symptoms of SLE had the improvement and the values of BUN, Creatinine were improved. But the symptoms of the stroke were not much changed.

• Tuberculosis and Respiratory Diseases
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• 제78권2호
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• pp.112-119
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• 2015

Primary thymic adenocarcinoma is a very rare malignancy of the anterior mediastinum with no standardized treatment. A 36-year-old male patient presented with hoarseness over the past 3 months. A chest computed tomography (CT) scan showed an infiltrative mass to the proximal vessels and aortic arch in left upper mediastinum ($4.1{\times}3.1{\times}5.4cm$). Brain magnetic resonance imaging (MRI) showed focal lesions, suggesting metastasis in the left frontal lobe. A thoracoscopic biopsy of the mediastinal mass confirmed a primary thymic adenocarcinoma forming a glandular structure with atypia of tumor cells. The patient received four cycles of systemic chemotherapy, consisting of etoposide and cisplatin, with concurrent radiotherapy (6,000 cGy/30 fractions) to the mediastinal lesion and the metastatic brain lesion (4,200 cGy/12 fractions). A follow-up chest CT scan and brain MRI showed a decrease in the size of the left upper mediastinal mass and brain lesion. We report a rare case of the primary thymic adenocarcinoma with a literature review.

• Journal of Chest Surgery
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• 제40권6호
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• pp.463-466
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• 2007

21세 남자 환자가 우측 손의 통증, 부종 및 저린감을 주소로 내원하였다. 정맥 조영술 및 MRI scan으로 Paget-Schroetter syndrome으로 진단되었으며, 혈전 용해술을 시행하였으나 호전이 없어 흉강경하에 1번 늑골 절제술을 시행하였다. 환자는 수술 후 증상이 호전되었으며, warfarin 처방과 함께 퇴원하였다. 통상적으로 알려진 1번 늑골 절제법은 경액와 접근법(transaxillary) 혹은 쇄골상부 접근법(supra-clavivular)등이 있으나, 본 증례의 경우 흉강경하에 1번 늑골 절제술을 시행하였고 이에 결과를 보고하는 바이다.

• 방사선산업학회지
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• 제11권3호
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• pp.139-144
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• 2017

To evaluation of clinical usefulness for B1+RMS limits, we compared image quality of Routine, Specific absorption rate (SAR) and Root mean square (RMS) protocol. 5 volunteers underwent Magnetic Resonance Imaging (MRI) scan of the brain using three different protocols. We draw Region of interest ROI in cortex, white matter, gray matter, putamen and thalamus of axial plan. Signal to noise ratio (SNR) were evaluated in each area and Contrast to noise ration (CNR) were evaluated between white matter and gray matter. Qualitative evaluation was used to score each ROI. B1+RMS is confirmed its usefulness compared to conventional SAR standard on the aspect of improvement of image quality, reduction of scan time and easy adjusting parameter.