• Korean Journal of Radiology
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• v.25 no.1
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• pp.74-85
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• 2024

Objective: Idiopathic intracranial hypertension (IIH) is a condition of unknown etiology associated with venous sinus stenosis. This study aimed to develop a magnetic resonance venography (MRV)-based radiomics model for predicting a high trans-stenotic pressure gradient (TPG) in IIH patients diagnosed with venous sinus stenosis. Materials and Methods: This retrospective study included 105 IIH patients (median age [interquartile range], 35 years [27-42 years]; female:male, 82:23) who underwent MRV and catheter venography complemented by venous manometry. Contrast enhanced-MRV was conducted under 1.5 Tesla system, and the images were reconstructed using a standard algorithm. Shape features were derived from MRV images via the PyRadiomics package and selected by utilizing the least absolute shrinkage and selection operator (LASSO) method. A radiomics score for predicting high TPG (≥ 8 mmHg) in IIH patients was formulated using multivariable logistic regression; its discrimination performance was assessed using the area under the receiver operating characteristic curve (AUROC). A nomogram was constructed by incorporating the radiomics scores and clinical features. Results: Data from 105 patients were randomly divided into two distinct datasets for model training (n = 73; 50 and 23 with and without high TPG, respectively) and testing (n = 32; 22 and 10 with and without high TPG, respectively). Three informative shape features were identified in the training datasets: least axis length, sphericity, and maximum three-dimensional diameter. The radiomics score for predicting high TPG in IIH patients demonstrated an AUROC of 0.906 (95% confidence interval, 0.836-0.976) in the training dataset and 0.877 (95% confidence interval, 0.755-0.999) in the test dataset. The nomogram showed good calibration. Conclusion: Our study presents the feasibility of a novel model for predicting high TPG in IIH patients using radiomics analysis of noninvasive MRV-based shape features. This information may aid clinicians in identifying patients who may benefit from stenting.

• Korean Journal of Radiology
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• v.20 no.5
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• pp.823-829
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• 2019

Objective: To summarize the high-resolution computed tomography (HRCT) and magnetic resonance imaging (HRMRI) features of duplicated internal auditory canals (DIACs). Materials and Methods: Ear HRCT data of 64813 patients with sensorineural hearing loss (SNHL), obtained between August 2009 and November 2017, were reviewed. Among these patients, 12 (13 ears) were found to have DIACs, 9 of whom underwent HRMRI. Their images were evaluated by two otoradiologists. Results: The rate of occurrence of DIAC among SNHL patients was 0.019% (12/64813). The internal auditory canals of 13 ears were divided into double canals by complete (n = 6) and incomplete (n = 7) bony septa, with varied orientations ranging from horizontal to approximately vertical. All of the anterosuperior canals extended into the facial nerve (FN) canal, except for 1, which also extended to the vestibule. The posteroinferior canals ended in the cochlea and vestibule, except for 2, which also connected to the FN canals. Magnetic resonance images revealed that 77.8% (7/9) and 22.2% (2/9) of vestibulocochlear nerves (VCNs) were aplastic and hypoplastic, respectively. Furthermore, 88.9% (8/9) of FNs were normal, except for 1, which was hypoplastic. All of the affected ears also had other ear anomalies: a narrow, bony cochlear nerve canal was the most common other anomaly, accounting for 92.3% (12/13). Malformations of other systems were not found. Conclusion: Double-canal appearance is a characteristic finding of DIAC on HRCT, and it is usually accompanied by other ear anomalies. The VCN usually appears aplastic, with a normal FN, on HRMRI.

• Proceedings of the KSMRM Conference
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• 2006.11a
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• pp.56-56
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• 2006

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.130-130
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• 2002

Purpose： To evaluate the liver enhancement pattern of MR images obtained after administration of manganese phthalocyanine (MnPC), which is a newly developed macromolecular MR contrast agent, In experimentally implanted VX2 tumor of rabbits and compare with G4-DTPA and Mn-DPDP.

• Journal of information and communication convergence engineering
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• v.2 no.3
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• pp.167-171
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• 2004

The evolution of modern imaging modalities, followed by the rapid development of computer technology has introduced many new features in the communication networks used in medical facilities. Since it is very important to keep patient's record accurately, the ability to exchange medical data securely over the communication network is essential for any medical information. In this paper, therefore, we introduce some problems which occur from digitizing medical images such as MRI (Magnetic Resonance Imaging), CT (Computed Tomography), CR(Computed Radiography), etc., and then we propose a authentication mechanism for medical image verification using secret watermark images.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.111-111
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• 2001

목적： To evaluate the feasibility of the event-related functional MR study using power grip studying the hand motor system 대상 및 방법： Event-related functional MRI was performed on a 1.5T MR unit in seven norm volunteers (man=7, right-handedness=2, left-handedness=5, mean age： 25 years). A single-shot GRE-EPI sequence (TR/TE/flip angle： 1000ms/40ms/90, FOV = 240 mm matrix= 64$\times$64, slice thickness/gap = 5mm/0mm, 7 true axial slices) was used for functiona MR images. A flow-sensitive conventional gradient echo sequence (TR/TE/flip angl 50ms/4ms/60) was used for high-resolution anatomical images. To minimize the gross hea motion, neck-holders (MJ-200, USA) were used. A series of MR images were obtained in axial planes covering motor areas. To exclude motion-corrupted images, all MR images wer surveyed in a movie procedure and evaluated using the estimation of center of mass of ima signal intensities. Power grip task consisted of the powerful grip of all right fingers and hand movement ta used very fast right finger tapping at a speed of 3 per 1 second. All tasks were visual-guid by LCD projector (SHARP, Japan). Two tasks consisted of 134 phases including 7 activatio and 8 rest periods. Active stimulations were performed during 2 seconds and rest period were 15 seconds and total scan time per one task was 2 min 14 sec. Statistical maps we obtained using cross-correlation method. Reference vector was time-shifted by 4 seconds an Gaussian convolution with a FWHM of 4 seconds was applied to it. The threshold in p val for the activation sites was set to be 0.001. All mapping procedures were peformed usin homemade program an IDL (Research Systems Inc., USA) platform. We evaluated the activation patterns of the motor system of power grip compared to hand movement in t event-related functional MRI.

• Journal of the Korean Society of Radiology
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• v.1 no.2
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• pp.23-30
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• 2007

This paper presents a method of generating 3-dimensional images by preprocessing 2-dimensional abdominal images obtained using CT (computed tomography) and MRI (magnetic resonance imaging) through segmentation, threshold technique, etc. and apply the method to virtual endoscopy. Three-dimensional images were visualized using indirect volume rendering, which can render at high speed using a general-purpose graphic accelerator used in personal computers. The algorithm used in the rendering is Marching Cubes, which has only a small volume of calculation. In addition, we suggested a method of producing 3-dimensional images in VRML (virtual reality modeling language) running on the Web browser without a workstation or an exclusive program. The number of nodes, the number of triangles and the size of a 3-dimensional image file from CT were 85,367, 174,150 and 10,124, respectively, and those from MRI were 34,029, 67,824 and 3,804, respectively.

• Journal of Korean Foot and Ankle Society
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• v.11 no.1
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• pp.18-22
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• 2007

Purpose: To provide basic data on anatomy of the ankle joint in adults using magnetic resonance imaging as well as to compare measurements with available data of corresponding dimension in the different sizes of the total ankle replacements design ($HINTEGRA^{(R)}$). Materials and Methods: Magnetic resonance (MR) sagittal and coronal images from one hundred-forty nine were studied. Post traumatic, arthritic, or grossly deformed ankles at any reason were excluded. Lengths, widths of the main parts of this articulation and also the radius of curvature of talar dome were measured in the MR images. Statistical analysis was performed on these measurements. Results: On MR coronal image data, average tibial width was $30.0{\pm}4.1\;mm$ and talar width was $27.0{\pm}3.4\;mm$. On sagittal image date, average anteroposterior length of the distal tibia was $39.0{\pm}4.2\;mm$, average anteroposterior length of the talus was $31.3{\pm}2.8\;mm$, and average sagittal radius of curvature of talar dome was $20.1{\pm}2.9\;mm$. All measurements in male were significantly larger than in female (p<0.01), but a significant difference according to age was not found. Conclusion: Ankle morphometric data define a basis of size, particularly useful in the design of ankle prostheses.

• Journal of Oral Medicine and Pain
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• v.25 no.1
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• pp.63-71
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• 2000

The authors assessed if there is a relationship between joint effusion and the presence of pain, and between joint effusion and disc displacement in 446 temporomandibular joints of 223 subjects who visited the Department of Oral Medicine, Kyungpook National University Hospital with the complaints of temporomandibular joint problem. The amount of joint effusion and the position of disc were determined from magnetic resonance images of the temporomandibular joints. The position of disc was classified into normal disc position, disc displacement with reduction (DDWR), and disc displacement without reduction (DDWOR). The amount of joint effusion was graded according to the extent of joint area of high signal intensity on T2-weighted MR images. These findings were correlated with one another and statistically analyzed. The results were as follows; 1. The incidence of temporomandibular joint pain Was higher in the joints with higher amount of joint effusion (P<0.001). 2. The proportion of temporomandibular joints with higher amount of effusion increased in the joints with more advanced articular disc displacement (P<0.001).

• Investigative Magnetic Resonance Imaging
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• v.10 no.2
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• pp.121-125
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• 2006

A 48-year-old man presented with a dermatofibrosarcoma protuberans (DFSP) of the scalp associated with local recurrence. Axial T1- and T2-weighted images demonstrated a well-circumscribed hypointense and intermediate hyperintense mass in the skin and subcutaneous layer of the scalp, respectively. Contrast-enhanced T1-weighted images showed the strongly enhanced mass invasion to the skin, subcutaneous layer and adjacent galeal layer. Scalp DFSP is very uncommon but is an aggressive tumor, so MR imaging diagnosis of the extent of the lesion to underlying structures, and initial wide local resection is important to prevent recurrence.