• Journal of the Korean Orthopaedic Association
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• v.54 no.5
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• pp.418-426
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• 2019

Purpose: This study analyzed the features of humeral head decentralization in large to massive rotator cuff tears with a shoulder dislocation in the elderly. Moreover, shoulder instability and treatment were reviewed. Materials and Methods: From May 2005 to February 2017, Group A containing 45 cases (45 patients) over 65 years old accompanied by a large or massive rotator cuff tear with a shoulder dislocation and Group B containing 45 cases (45 patients) without a shoulder dislocation were enrolled. The mean ages in Groups A and B were 73.2 and 72.1 years old, and the mean follow-up periods were 30.7 and 31.3 months, respectively. Twenty-one cases (46.7%) in Group A underwent rotator cuff repair, and 8 cases (17.8%) underwent concomitant rotator cuff repair with Bankart repair. Sixteen cases (35.6%) underwent reverse total shoulder arthroplasty for cuff tear arthropathy. 45 cases (100%) in Group B underwent rotator cuff repair. The off-the center and head elevation were measured in the preoperative magnetic resonance imaging (MRI) of Groups A and B. The preoperative and postoperative visual analogue scale (VAS) score, American Shoulder and Elbow Surgeons (ASES) score, and University of California Los Angeles (UCLA) score in Groups A and B were compared. Results: In Groups A and B, the mean off-the centers were posterior 7.41 mm and posterior 2.02 mm (p=0.03), and the mean head elevations were superior 6.66 mm and superior 2.44 mm (p=0.02), respectively. The mean ASES scores of Groups A and B were 32.8 and 33.4 before surgery, and 77.1 (p=0.02) and 78.1 (p=0.02) after surgery (p=0.18), respectively. The mean UCLA scores of Groups A and B were 13.1 and 12.8 before surgery, and 28.9 (p=0.02) and 29.5 (p=0.01) after surgery (p=0.15), respectively. Conclusion: Patients over 65 years old with a shoulder dislocation in large to massive rotator cuff tears had higher off-the center and head elevation on the preoperative MRI than those without a shoulder dislocation. This measurement can help predict preceding shoulder instability. Early rotator cuff repairs should be performed and other treatments, such as Bankart repair and reverse total shoulder arthroplasty, should also be considered.

• Journal of the Korean Society of Radiology
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• v.82 no.2
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• pp.406-416
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• 2021

Purpose To evaluate the association between magnetic resonance imaging (MRI)-based texture parameters and Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation in patients with non-mucinous rectal cancer. Materials and Methods Seventy-nine patients who had pathologically confirmed rectal non-mucinous adenocarcinoma with or without KRAS-mutation and had undergone rectal MRI were divided into a training (n = 46) and validation dataset (n = 33). A texture analysis was performed on the axial T2-weighted images. The association was statistically analyzed using the Mann-Whitney U test. To extract an optimal cut-off value for the prediction of KRAS mutation, a receiver operating characteristic curve analysis was performed. The cut-off value was verified using the validation dataset. Results In the training dataset, skewness in the mutant group (n = 22) was significantly higher than in the wild-type group (n = 24) (0.221 ± 0.283; -0.006 ± 0.178, respectively, p = 0.003). The area under the curve of the skewness was 0.757 (95% confidence interval, 0.606 to 0.872) with a maximum accuracy of 71%, a sensitivity of 64%, and a specificity of 78%. None of the other texture parameters were associated with KRAS mutation (p > 0.05). When a cut-off value of 0.078 was applied to the validation dataset, this had an accuracy of 76%, a sensitivity of 86%, and a specificity of 68%. Conclusion Skewness was associated with KRAS mutation in patients with non-mucinous rectal cancer.

• Progress in Medical Physics
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• v.9 no.1
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• pp.1-9
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• 1998

In order to provide complementary image data, CT(computed tomography), MR(magnetic resonance) and angiography have been used in the field of Stereotactic Radiosurgery(SRS) and neurosurgery. The aim of this work is to develop 3-D stereotactic localization system in order to determine the precise shape, size and location of the lesion in the brain in the field of Stereotactic Radiosurgery(SRS) and neurosurgery using multi-image modality and multi purpose QA phantom. In order to obtain accurate position of a target, Hitchcoke stereotactic frame and CT/angiography localizers were rigidly attached to the phantom with nine targets dispersed in 3-D space. The algorithms to obtain a 3-D stereotactic coordinates of the target have been developed using the images of the geometrical phantom which were taken by CT/angiography. Positions of targets computed by our algorithms were compared to the absolute position assigned in the phantom. Outlines of targets on each CT image were superimposed each other on angiography images. A spatial mean distance errors were 1.02${\pm}$0.17mm for CT with a 512${\times}$512 matrix and 2mm slice thickness, 0.41${\pm}$0.05mm for angiogra- phy localization. The resulting accuracy in the target localization suggests that the developed system has enough Qualification for Stereotactic Radiosurgery (SRS).

• Investigative Magnetic Resonance Imaging
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• v.6 no.1
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• pp.35-40
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• 2002

Purpose : To evaluate the NMR relaxation properties and imaging characteristics of tissue-specificity for a newly developed macromolecular MR agent. Materials and methods : Phthalocyanine (PC) was chelated with paramagnetic ion, Mn.2.01g (5.2 mmol) of Phthalocyanine was mixed with 0.37g (1.4 mmol) of Mn chloride at $310^{\circ}C$ for 36 hours and then purified by chromatography (CHC13/CH3OH 98/2 v/v, Rf, 0.76) to obtain 1.04g (46%) of MnPC (molecular weight= 2000d). The $T1}T2$ relaxivity of MnPC was measured in 1.5T(64 MHz) MR using 0.1 mM MnPC. The MR image characteristics of MnPC was evaluated using spin-echo (TR/TE=500/14 msec) and gradient-echo (FLASH) (TR/TE=80/4 msec, flip angle=60) techniques in 1.57 MR scanner. The images of rabbit liver were obtained every 10 minutes up to 4 hours. To study the effect of concentration on image, 20 mM, 50 mM, 100 mM of MnPC were tested. Results : The relaxivities of MnPC at 1.5T(64MHz) were Rl=7.28 $mM^{-1}S^{-1},{\;}R2=55.56mM^{-1}S^{-1}$. Compared to the values of Gd-DTPA (Rl[=4.8 $mM^{-1}S^{-1})$], R2[=5.2 $mM^{-1}S^{-1}])$]), both T1/T2 relaxivities of MnPC were higher than those of Gd-DTPA. For both of SE and FLASH techniques, the contrast enhancement reached maximum at 10 minutes after bolus injection and the enhancement continued for more than 2 hours. When compared with small molecular weight liver agents such as Gd-EOB-DTPA, Gd-BOPTA and MnDPDP, MnPC was characterized by more prolonged enhancement time. The time course of MR images also revealed biliary excretion of MnPC. Conclusion : We developed a new macromolecular MR agent, MnPC. The relaxivities of MnPC were higher than those of small molecular weight Gd-chelate. Hepatic uptake and biliary excretion of MnPC suggests that this agent is a new liver-specific MR agent.

• The Journal of the Korean bone and joint tumor society
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• v.7 no.1
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• pp.28-35
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• 2001

Purpose : Authors investigated the efficiency of preoperative MRI in suspicious glomus tumor and the clinical outcomes after marginal excision. Materials and Methods : In 10 cases of glomus tumors in the fingers, authors retrospectively analyzed the clinical data, including previous trauma, treatment history, preoperative symptoms, physical examination, plain radiography, MRI (9 cases), pathological findings and postoperative complications. Results : The patients had pain in 10 cases, tenderness in 9 cases, cold sensitivity in 3 cases and edema in one case. MRI showed low signal (3 cases) or iso-signal (5) intensity on T1 weighted image, high signal intensity (8) on T2 weighted image, and all the lesions were enhanced in gadolinium enhancement images. The exact locations of glomus tumors were median in 6 cases, lateral in 5, lateral fold in 2 and pulp in 3 in transverse section and nail bed in 5 cases and nail matrix in 5 in sagittal section. Marginal excision was performed by lateral approach in one case and transungual in 9 cases. Histologically, all 10 cases were composed of solid sheets of round cells interrupted by thin-walled blood vessels. Most of clinical symptoms were disappeared in all cases after operation. Nail deformity was found in one case, which was originated from nail matrix, however, there was no recurrence. Summary : Clinical symptom was the most impotant factor in diagnosis of glomus tumor in the fingers. However, preoperative MRIs were helpful in patients, who had obscure pain or prolonged clinical symptoms with suspicious glomus tumors. Preoperative MRI might be one of the most useful tools for establishing the exact diagnosis and detecting the location of glomus tumors, in spite of the relatively high expenses.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4380-4386
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• 2014

This study was conducted to minimize the imaging distortion by reducing the differences in susceptibility between the tissue and air surrounding it while performing a thyroid diffusion imaging procedure. The study group was composed of 23 healthy adults. Thyroids with many distortions near the air, larynx, and trachea were chosen to test and evaluate the diffusion imaging difference between before and after an application of silicon. As a result, there was reduced distortion with silicon application, and the differences decreased from 30% to 10%. According to One-way ANOVA and Duncan's post-hoc test, there were no significant differences between imaging with a silicon application and T2 imaging of the surface area, which was the standard image. In conclusion, this study presented a radical improvement in reducing the distortions in imaging by compensating for an uneven tissue surface near air without affecting the magnetic resonance contrast and complicating the imaging processes.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.5
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• pp.462-469
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• 2000

Positron Emission Tomography(PET) is a new diagnostic method that can create functional images of the distribution of positron emitting radionuclides, which when administered intravenously in the body, makes possible anatomical and functional analysis by quantity of biochemical and physiological process. After genetic and biochemical changes in initial stage, malignant tumor undergoes functional changes before undergoing anatomical changes. So, early diagnosis of malignant tumors by functional analysis with PET can be achieved, replacing traditional anatomical analysis, such as computed tomography(CT) and magnetic resonance image(MRI), etc. Similarly, PET can identify malignant tumor without confusion with scar and fibrosis in follow up check. In the Korea Cancer Center Hospital(KCCH) from October 1997 to September 1999, clinical study was performed in 79 cases that underwent 89 times PET evaluation with [18F]-Fluorodeoxyglucose for diagnosis of oral and maxillofacial tumors, and the data was analysed by Bayesian $2{\times}2$ Classification Table. The results were as follows : Evaluation for initial diagnosis with FDG-PET (P<0.005) 1. Agreement rate or accuracy rate is 88.9%. 2. Sensitivity is 95.2%, and specificity 66.7%. 3. Positive predictive rate is 90.9%, and negative predictive rate 80.0%. 4. In consideration of tumor stage, diagnostic rate in less than stage II was 90% and in greater than stage III 100%. 5. In consideration of tumor size, diagnostic rate in less than T2 was 92.3% and in greater than T3 100%. After primary treatment, evaluation for follow up check with FDG-PET (P < 0.001) 1. Agreement rate or accuracy rate is 85.4%. 2. Sensitivity is 87.5%, and specificity 82.4%. 3. Positive predictive rate is 87.5%, and negative predictive rate 82.4%. 4. In 24 recurred cases, 6 had distant metastasis, and 5 of them were diagnosed with FDG-PET, resulting in diagnostic rate of FDG-PET of 83.3%. From the above results, Positron Emission Tomography with [18F]- Fluorodeoxyglucose appears to be more sensitive and accurate for detecting the presence of oral and maxillofacial tumors, and has various clinical applications such as early diagnosis of tumor in initial and follow up check and detection of distant metastasis.

• Journal of Korean Neurosurgical Society
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• v.29 no.12
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• pp.1606-1611
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• 2000

Objective : To obtain more reliable sample in stereotactic biopsy, authors adopted proton chemical shift imaging ($^1H$-CSI)-directed biopsy. Until now, proton single voxel spectroscopy($^1H$-SVS) technique has been reported as a technique using metabolic information in stereotactic biopsy. The authors performed $^1H$-CSI with a stereotactic headframe in place and evaluated the pathologic results obtained from local metabolic information through $^1H$-CSI. Methods : $^1H$ CSI-directed stereotactic biopsy was performed in four patients. $^1H$-CSI and conventional Gd-enhancement stereotactic MRI was done simultaneously after application of the stereotatic frame. After reconstruction of metabolic maps of NAA/Cr, Cho/Cr, and Lactate/Cr ratios, the focal areas of increased Cho/Cr ratios and decreased NAA/Cr ratios were selected for target sites in the MR images Results : There was no difficulty in performing $^1H$-CSI with the stereotactic headframe in place. In pathologic examinations, the samples taken in area of increased Cho/Cr ratios and decreased NAA/Cr ratios showed the features of increased cellularity, mitoses and cellular atypism, thus facilitated the diagnosis. The pathologic samples taken from the area of increased Lactate/Cr ratios showed prominent feature of necrosis. Conclusion : $^1H$-CSI was feasible with stereotactic head frame in place. The final pathologic results obtained in our samples were concordant with the local metabolic informations from $^1H$-CSI. Authors believe that $^1H$ CSI-directed stereotactic biopsy may provide us advantages in obtaining more reliable tissue specimen in stereotactic biopsy.

• Advances in nano research
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• v.1 no.3
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• pp.159-169
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• 2013

A preparation method for gadolinium compound (GdC) nanoparticles coated with silica ($GdC/SiO_2$) is proposed. GdC nanoparticles were prepared with a homogeneous precipitation method at $80^{\circ}C$ using $1.0{\times}10^{-3}$ M $Gd(NO_3)_3$, 0.5 M urea and $0-3.0{\times}10^{-4}$ M ethylenediarinnetetraacetic acid disodium salt dihydrate (ETDA) in water. As a result of preparation at various EDTA concentrations, GdC nanoparticles with a size as small as $40.5{\pm}6.2$ nm, which were colloidally stable, were prepared at an EDTA concentration of $2.0{\times}10^{-4}$ M. Silica-coating of the GdC nanoparticles was performed by a St$\ddot{o}$ber method at $35^{\circ}C$ using $1.0-10.0{\times}10^{-3}$ M tetraethylorthosilicate (TEOS), 11 M $H_2O$ and $1.5{\times}10^{-3}$ M NaOH in ethanol in the presence of $1.0{\times}10^{-3}$ M GdC nanoparticles. Performance of preparation at various TEOS concentrations resulted in production of $GdC/SiO_2$ particles with an average size of $106.1{\pm}11.2$ nm at a TEOS concentration of $5.0{\times}10^{-3}$ M. The gadolinium (Gd) concentration of $1.0{\times}10^{-3}$ M in the as-prepared $GdC/SiO_2$ particle colloid solution was increased up to a Gd concentration of 0.2 M by concentrating with centrifugation. The core-shell structure of $GdC/SiO_2$ particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The concentrated $GdC/SiO_2$ colloid solution showed images of X-ray and magnetic resonance with contrast as high as commercial Gd complex contrast agents.

• Journal of the Korean Society of Radiology
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• v.81 no.4
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• pp.912-919
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• 2020

Purpose This study aimed to compare the brain perfusion status of patients with chronic kidney disease to a normal control group to identify any significant differences. Materials and Methods The perfusion state of the brain was measured by MRI using the arterial spin labeling technique in 36 patients undergoing hemodialysis due to chronic kidney disease and 36 normal controls. Images were then analyzed in a voxel-wise manner to detect brain areas showing significant perfusion differences between the two groups. Results Patients with chronic kidney disease showed increased perfusion in the form of large clusters across the right fronto-parieto-temporal lobe and the left parieto-occipital lobe. In addition, perfusion increased in the bilateral thalami, midbrain, pons, and cerebellum (p < 0.01, familywise error corrected). Conclusion Brain perfusion appears to increase in patients with chronic kidney disease compared to normal controls. Uremic toxicity is thought to be the cause of this increase as it can cause damage to the microscopic blood vessels and their surrounding structures.