• Journal of the Korean Society of Radiology
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• v.82 no.1
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• pp.212-218
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• 2021

Ewing sarcomas constitute a group of small, round, blue cell tumors of the bone and soft tissue. Extraskeletal Ewing sarcoma (EES) is a rare malignant neoplasm that arises from soft tissues, and it usually affects children and young adults. EES of the thoracopulmonary region commonly presents with a palpable mass or pain. Although rarely reported, EES affecting the anterior chest wall may present as a breast mass. We report a case of EES arising from the chest wall and manifesting as a palpable breast mass in a 22-year-old woman. The large mass was initially misdiagnosed as a breast origin mass on ultrasonography, but subsequent CT and MRI showed that the mass originated from the chest wall. Radiologists should be aware of the imaging findings of EES, and they should understand that chest wall lesions may be clinically confused as breast lesions.

• Journal of the Korean Society of Radiology
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• v.81 no.4
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• pp.979-984
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• 2020

Cri-du-chat syndrome is a rare genetic disorder in which the patient presents with a characteristic high-pitched monotonous cry and recurrent aspiration pneumonia, attributed to abnormalities in the larynx, epiglottis, and nervous system. The most prominent brain MRI findings are the presence of pontine and cerebellar hypoplasia, which primarily involve posterior cranial fossa structures. Although atrophy of supratentorial structures were also a common radiological finding, it was considered to be a secondary change due to pontine hypoplasia. Here, we present the case of a three-month-old patient presenting with cri-du-chat at our institution. The patient also showed the presence of prominent pontine hypoplasia similar to previously reported cases; however, contrary to other cases, there was a general delayed myelination of brain instead of decreased myelination of anterior limb of internal capsule. Since the larynx, pons, and cerebellum all originated from similar notochord level, which suggests anomaly in early stage of development, laryngeal, and brain anomaly characteristically observed in the cridu-chat syndrome.

• The Korean Journal of Nuclear Medicine
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• v.37 no.1
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• pp.63-72
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• 2003

Functional MRI (fMRI) provides an indirect mapping of cerebral activity, based on the detection of the local blood flow and oxygenation changes following neuronal activity (Blood Oxygenation Level Dependent). fMRI allows us to study noninvasively the normal and pathological aspects of functional cortical organization. Each fMRI study compares two different states of activity. Echo-Planar Imaging is the technique that makes it possible to study the whole brain at a rapid pace. Activation maps are calculated from a statistical analysis of the local signal changes. fMRI is now becoming an essential tool in the neurofunctional evaluation of normal volunteers and many neurological patients as well as the reference method to image normal or pathologic functional brain organization.

• Journal of Biomedical Engineering Research
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• v.24 no.4
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• pp.339-346
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• 2003

MRI provides anatomical structure information with superb spatial resolution that can be utilized in clinical surgeries. Advanced image processing techniques in conjunction with the MRI-guided surgery is expected to be of great importance in brain surgeries in the near future. In this paper, we introduce an image-guided surgery technique using the stereo matching method. To perform image-guided biopsy operations, we made MRI markers, camera markers and a detection probe marker. To evaluate the accuracy of the image-guided system. we made a silicone phantom. Using the phantom and markers, we have performed MRI-guided experiments with a 1.5 Tesla MRI system. It has been verified from phantom experiments that our system has a positioning error less than 1.5%. Compared with other image guided surgery system, our system shows better positioning accuracy.

• Investigative Magnetic Resonance Imaging
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• v.17 no.2
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• pp.110-122
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• 2013

Purpose : To compare the image quality and ligament traceability in ankle images obtained using Volume Isotropic Turbo Spin Echo Acquisition (VISTA) MRI with and without fat suppression. Materials and Methods: The signal-to-noise ratios (SNRs) in images from a phantom and from the ankle of a volunteer were compared. Ten ankles from 10 non-symptomatic volunteers were imaged for comparisons of contrast ratio (CR) and ligament traceability. All examinations were performed using VISTA sequences with and without fat suppression on a 3T MRI scanner. The SNRs were obtained from images with subjects and without subjects (noise-only). Contrast ratios from images of the 10 ankles were acquired between fluid and tendon (F-T), F-cartilage (C), F-ligament (L), fat (f)-T, f-C and f-L. Two musculoskeletal radiologists independently scored the traceability of 7 ligaments, in sagittal, axial and coronal images respectively, based on a 4-point scale (1 as not traceable through 4 as clearly traceable). The Wilcoxon signed-rank test was used to compare the CR. Fisher's exact test and Pearson's chi-squared test were used to compare the ligament traceability. Results: The SNRs did not differ significantly between the two sequences except in bone marrow. VISTA SPAIR showed the higher CR only in F-T (p = 0.04), whereas VISTA showed higher CR in f-T (p = 0.005), f-C (p = 0.005) and f-L (p = 0.005). The calcaneofibular ligament traceability with VISTA was superior to that obtained with VISTA SPAIR (p < 0.05) in all planes. Conclusion: VISTA showed significant superiority to VISTA SPAIR in tracing CFL due to the superior CR between fat and ligament.

• Journal of Chest Surgery
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• v.32 no.8
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• pp.768-771
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• 1999

A 45 year old man was admitted for further examination of an abnormal shadow of the right posterior mediastinum. The patient suffered from dysesthesia in the right thoracic wall of dermatome T7. CT scan and MRI revealed that two separate tumors had developed in the right paravertebral area linked to the vertebral canal via an intervertebral foramina. One-stage removal of the tumors were performed safely through the right posterolateral thoracotomy following the resection of the rib head and vertebral pedicle. The tumors were confirmed as histologically neurilemomas. The postoperative course was uneventful.

• Investigative Magnetic Resonance Imaging
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• v.7 no.1
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• pp.12-21
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• 2003

Purpose : In order to overcome limitations in the existing conventional spectrometer, a new spectrometer with advanced functionalities is designed and implemented. Materials and Methods : We designed a spectrometer using the TMS320C6701 DSP capable of 1 giga floating point operations per second (GFLOPS). The spectrometer can generate continuously varying complicate gradient waveforms by real-time calculation, and select image plane interactively. The designed spectrometer is composed of two parts: one is DSP-based digital control part, and the other is analog part generating gradient and RF waveforms, and performing demodulation of the received RF signal. Each recover board can measure 4 channel FID signals simultaneously for parallel imaging, and provides fast reconstruction using the high speed DSP. Results : The developed spectrometer was installed on a 1.5 Tesla whole body MRI system, and performance was tested by various methods. The accurate phase control required in digital modulation and demodulation was tested, and multi-channel acquisition was examined with phase-array coil imaging. Superior image quality is obtained by the developed spectrometer compared to existing commercial spectrometer especially in the fast spin echo images. Conclusion : Interactive control of the selection planes and real-time generation of gradient waveforms are important functions required for advanced imaging such as spiral scan cardiac imaging. Multi-channel acquisition is also highly demanding for parallel imaging. In this paper a spectrometer having such functionalities is designed and developed using the TMS320C6701 DSP having 1 GFLOPS computational power. Accurate phase control was achieved by the digital modulation and demodulation techniques. Superior image qualities are obtained by the developed spectrometer for various imaging techniques including FSE, GE, and angiography compared to those obtained by the existing commercial spectrometer.

• Korean Journal of Digital Imaging in Medicine
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• v.13 no.2
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• pp.55-58
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• 2011

It is important to study using experimental animals for research about stroke. Magnetic Resonance Imaging(MRI) is avaluable diagnosticmethods for stroke diagnosis. The purpose of this research is to know the Magnetic Resonance Imaging(MRI) and histopathological characteristics findings after induction of photothrombotic cerebral infarction in rat brain. Male Sprague-Dawley rats were anesthetized, Rose Bengal dye(20 mg/kg) was intravenously injected. The right sensonrimotor cortex of rat brain was exposed to cold light of 7 mm diameter at a position of 1 mm anterior and 3.5 mm lateral to bregma for 20 min. The post-infarction effects were monitored by T1 weighted and T2 weighted images of brain MRI. Histopathological changes were observed after Hematoxylin & Eosin staining. The lesion appeared clearly high signal intensity area on T2 weighted images(the major axis $7.04{\pm}0.11$ mm, the minor axis $3.08{\pm}0.04$ mm) and also H&E staining was same result. In conclusion, MRI was avaluable diagnostic methods for diagnosis and serial changes of stroke.

• Imaging Science in Dentistry
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• v.35 no.2
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• pp.69-75
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• 2005

Purpose : To determine the clinical correlation of magnetic resonance imaging (MRI) findings of temporomandibular joint internal derangements. Materials and Methods : The MR images of 150 TMJs in 75 patients were analyzed. The clinical symptoms were pain in the preauricular area and masticatory muscles and TMJ sounds. Results : There was a statistically significant relationship between the MRI diagnoses of different types of disc displacements and clinical findings of pain, clicking, and crepitus. The risk of TMJ pain was increased when the disc displacement without reduction occurred at the same time in combination with the osteoarthrosis and effusion. Conclusion : Regardless of the results, the data indicate that each of these MR imaging variables may not be regarded as the unique and dominant factor in defining TMJ pain occurrence.

• Journal of the Korean Society of Radiology
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• v.84 no.1
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• pp.75-91
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• 2023

The technical parameters and imaging interpretation criteria of the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) using multiparametric MRI (mpMRI) are updated in PI-RADS v2.1. These changes have been an expected improvement for prostate cancer evaluation, although some issues remain unsolved, and new issues have been raised. In this review, a brief overview of PI-RADS v2.1 is and several critical points are discussed as follows: the need for more detailed protocols of mpMRI, lack of validation of the revised transition zone interpretation criteria, the need for clarification for the revised diffusion-weighted imaging and dynamic contrast-enhanced imaging criteria, anterior fibromuscular stroma and central zone assessment, assessment of background signal and tumor aggressiveness, changes in the structured report, the need for the parameters for imaging quality and performance control, and indications for expansion of the system to include other indications.