• Journal of radiological science and technology
• /
• v.41 no.6
• /
• pp.553-560
• /
• 2018

PET-CT and PET-MRI which integrates CT using ionized radiation and MRI using phenomena of magnetic resonance are determined to have the limitation to apply the semi-quantitative index, standardized uptake value (SUV), with the same level due to the fundamental differences of image capturing principle and reorganization, hence, their correlations were analyzed to provide their clinical information. To 30 study subjects maintaining pre-treatment, $^{18}F-FDG$ (5.18 MBq/㎏) was injected and they were scanned continuously without delaying time using $Biograph^{TM}$ mMR 3T (Siemens, Munich) and Biograph mCT 64 (Siemens, Germany), which is an integral type, under the optimized condition except the structural differences of both scanners. Upon the measurement results of $SUV_{max}$ setting volume region of interest with evenly distributed radioactive pharmaceuticals by captured images, $SUV_{max}$ mean values of PET-CT and PET-MRI were $2.94{\pm}0.55$ and $2.45{\pm}0.52$, respectively, and the value of PET-MRI was measured lower by $-20.85{\pm}7.26%$ than that of PET-CT. Also, there was a statistically significant difference in SUVs between two scanners (P<0.001), hence, SUV of PET-CT and PET-MRI cannot express the clinical meanings in the same level. Therefore, in case of the patients who undergo cross follow-up tests with PET-CT and PET-MRI, diagnostic information should be analyzed considering the conditions of SUV differences in both scanners.

• Clinics in Shoulder and Elbow
• /
• v.22 no.2
• /
• pp.61-69
• /
• 2019

Background: The purpose of this study is to compare the clinical outcomes of the control group and platelet-rich plasma (PRP) group among the patients who failed to respond to conservative treatment as outpatient-based therapy for rotator cuff tendinopathy, and to compare the clinical results of leukocyte-poor (LP) PRP and leukocyte-rich (LR) PRP. Methods: Inclusion criteria are (1) over 18-year-old, (2) patients with rotator cuff tendinopathy, no rotator cuff tear by radiologic diagnosis (ultrasonography or magnetic resonance imaging) within the last 3 months, and (3) not effective to conservative treatment for more than 1 month. Of the final 60 subjects, 33 patients in the exercise treatment group and 27 patients in the PRP injection group (LP-PRP, 13; LR-PRP, 14) were included. Clinical evaluation was carried out by assessing the outcomes of treatment using the Numeric Rating Scale pain score, the American Shoulder and Elbow Society (ASES) score, and the Constant score at baseline and at 3 and 6 months after the procedure. Results: There was a statistically significant difference in ${\Delta}ASES_{3months}$ ($ASES_{3months}-ASES_{first}$) score between the control and PRP groups (p=0.006). However, there was no statistical significance between LP-PRP and LR-PRP groups (p>0.05). Conclusions: This study showed that PRP injection was more effective than exercise therapy for the first 3 months. However, there was no difference between the LP-PRP group and the LR-PRP group. Regardless of the type of PRP, clinical application of PRP injection in patients with rotator cuff tendinopathy seems to be effective in early treatment.

• Archives of Plastic Surgery
• /
• v.46 no.1
• /
• pp.23-33
• /
• 2019

Background Venous malformations (VMs) are a common type of vascular malformation. However, their causes and management remain unclear, and few studies specific to VMs of the head and neck have been reported. This study describes our experiences with VMs of the head and neck. Methods This retrospective study included 82 patients who underwent treatment for head and neck VMs, among 222 who visited our vascular anomalies center. Medical records between 2003 and 2016 were reviewed to identify common features in the diagnosis and treatment. The diagnosis of suspected head and neck VMs was based on the results of imaging studies or biopsies, and the VMs were analyzed based on magnetic resonance imaging, computed tomography, and Doppler sonography findings. Results VMs were slightly more common in female patients (59.8%), and 45.1% of patients developed initial symptoms at the age of 10 or younger. Lesions were slightly more common on the right side (47.3%). The main sites involved were the cheek (27.7%) and lip area (25.5%). The muscle layer was commonly involved, in 98.7% of cases. Small lesions less than 5 cm in diameter accounted for 60.8% of cases, and well-defined types were slightly more prevalent at 55.4%. Improvement was observed in 77.1% of treated patients. Conclusions Early and accurate diagnosis and appropriate treatment according to individual symptoms are important for successful treatment of VMs. If treatment is delayed, the lesions can worsen, or recurrence becomes more likely. Therefore, VMs require a multidisciplinary approach for early and accurate diagnosis.

• Clinics in Shoulder and Elbow
• /
• v.22 no.4
• /
• pp.203-209
• /
• 2019

Background: Clinical outcomes and prognosis of large and massive rotator cuff tears are known to be unpredictable not only in degeneration of the rotator cuff, but also due to a high rate of retear. Methods: Totally, 81 patients who had undergone arthroscopic rotator cuff repair from May 2008 to February 2016 were evaluated in our study. Clinical and functional evaluations were performed with the Constant score and the University of California, Los Angeles (UCLA) score, as well as full physical examination of the shoulder. All patients were confirmed to have magnetic resonance imaging (MRI) of tendon healing at least 1 year postoperatively. Results: The average age at the time of surgery was 65 years (range, 47-78 years). The average duration of postoperative time in which a follow-up MRI was performed was 36.1 months (range, 12-110 months). Large tears were present in 48 cases (59.3%) and massive tears in 33 cases (40.7%). Overall, there were 33 retear cases (40.7%). All the average clinical outcome scores were significantly improved at the last follow-up (p<0.001), although repair integrity was not maintained. Compared to type A, types C, and D of the Collin's classification showed significantly higher retear rates (p=0.036). Conclusions: Arthroscopic rotator cuff repair yields improved clinical outcomes and a relatively high degree of patient satisfaction, despite the repair integrity not being maintained. Involvement of the subscapularis muscle or infraspinatus muscle had no effect on the retear rate.

• The Journal of Korean Institute of Information Technology
• /
• v.17 no.3
• /
• pp.43-50
• /
• 2019

In this paper, we propose a S-band oscillator with a reduced electrical size by applying a vertical split ring resonator(VSRR). The VSRR is a type of split ring resonator that operates as a resonator by the capacitance and inductance generated between the microstrip lines arranged on the top and bottom of the dielectric substrate and it has an advantage that the electrical size of the resonance circuit can be reduced as compared with the conventional ring resonator. In this paper, we design a VSRR operating over S-band and an oscillator using the VSRR as the resonant circuit. The proposed oscillator showed the output of 5.9dBm at 2.4HGz and showed the phase noise characteristics of -112.58dBc at 100KHz offset frequency and -117.85dBc at 1MHz offset.

• Journal of Korean Association for Spatial Structures
• /
• v.20 no.4
• /
• pp.149-158
• /
• 2020

The governing equation for a dome-type shallow spatial truss subjected to a transverse load is expressed in the form of the Duffing equation, and it can be derived by considering geometrical non-linearity. When this model under constant load exceeds the critical level, unstable behavior is appeared. This phenomenon changes sensitively as the number of free-nodes increases or depends on the imperfection of the system. When the load is a periodic function, more complex behavior and low critical levels can be expected. Thus, the dynamic unstable behavior and the change in the critical point of the 3-free-nodes space truss system were analyzed in this work. The 4-th order Runge-Kutta method was used in the system analysis, while the change in the frequency domain was analyzed through FFT. The sinusoidal wave and the beating wave were utilized as the periodic load function. This unstable situation was observed by the case when all nodes had same load vector as well as by the case that the load vector had slight difference. The results showed the critical buckling level of the periodic load was lower than that of the constant load. The value is greatly influenced by the period of the load, while a lower critical point was observed when it was closer to the natural frequency in the case of a linear system. The beating wave, which is attributed to the interference of the two frequencies, exhibits slightly more behavior than the sinusoidal wave. And the changing of critical level could be observed even with slight changes in the load vector.

• Journal of Korean Physical Therapy Science
• /
• v.28 no.3
• /
• pp.42-52
• /
• 2021

Background: The purpose of this study was to investigate the effects of the severity and direction of lumbar disc herniation (LDH) on the facet joints and paraspinal muscles. Design: Cross-sectional design. Methods: The subjects were divided according to the diagnosis for severity of unilateral herniation of L4-L5 disc. The groups consisted of disc protrusion group (n=15), disc extrusion group (n=15), and no disc herniation group (n=15). The asymmetry and angle of facet joints and the cross-sectional area of paraspinal muscles were analyzed and compared using magnetic resonance imaging (MRI). Results: The results showed that the angle of facet tropism was larger in disc extrusion group than the disc protrusion group and the difference was found to be significant difference (p<0.01). In addition, when both left and right angles of patients with unilateral disc herniation were measured, the results showed larger facet joint angle in the herniated area of the disc extrusion group than in the disc protrusion group. When paraspinal muscles were measured according to the severity of disc herniation and the degree of facet joint asymmetry, there was no difference in paraspinal muscles between the disc protrusion and disc extrusion groups. Meanwhile, the multifidus muscle was smaller in the group with facet tropism than the group without facet tropism (p<0.03), while there were no significant differences in the erector spinae and psoas muscles. Conclusion: Progression of disc herniation resulted in increased facet joint tropism, increased angle of the facet joints in the direction of disc herniation, and decreased size of the multifidus muscle.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.35 no.3
• /
• pp.303-307
• /
• 2022

Magnetoelectric (ME) properties of 3-0 type particulate composites have been investigated with respect to application features for reliable magnetic sensitivity and magnetically-induced output voltage. In order to figure out the magnetoelectric characteristics in the ME composites, frequency dependent ME responses were studied from [0.948 Na_0.5K_0.5NbO₃-0.052 LiSbO₃]-[Co_1-xZn_xFe₂O₄] (NKNLS)/Co_1-xZn_xFe₂O₄ (CZFO, x=0, 0.1, and 0.2). As a result, the maximal α_ME of 23.15 mV/cm·Oe was achieved from the NKNLS-CZFO (x_Zn = 0.1) composites at resonance frequency of 315 kHz and H_dc = 0 Oe. From the frequency dependent ME responses, it is clearly described that the self-biased ME composites can be used for applications as both magnetic sensors and energy harvesters, respectively.

• Journal of the Korean Wood Science and Technology
• /
• v.30 no.3
• /
• pp.1-11
• /
• 2002

This study was conducted to investigate the effects of reaction pH conditions and hardener types on the reactivity, chemical structure and adhesion performance of UF resins. Three different reaction pH conditions, such as traditional alkaline-acid (7.5 → 4.5), weak acid (4.5), and strong acid (1.0), were used to synthesize UF resins which were cured by adding three different hardeners (ammonium chloride, ammonium citrate, and zinc nitrate) to measure adhesion strength. Fourier transform infrared (FT-IR) and carbon-13 nuclear magnetic resonance (¹³C-NMR) spectroscopies were employed to study chemical structure of the resin prepared under three different reaction pH conditions. Adhesion strength of the resins cured with three different hardeners was determined with lap shear specimens in tension. The gel time of UF resins decreased with an increasing in the amount of both ammonium chloride and ammonium citrate added in the resins. However, the gel time increased for zinc nitrate. Both FT-IR and ¹³C-NMR spectroscopies showed that the strong reaction pH condition produce uronic structures in UF resin, while both alkaline-acid and weak acid conditions produce quite similar chemical species in the resins. The maximum adhesion strength was occurred with the resin prepared under strong acid pH condition. However, this study indicated that the weak acid reaction condition provide a balance between increasing resin reactivity and improving adhesion strength of UF resin. The measurement of formaldehyde emission from the panels bonded with the UF resins prepared is planned for future work.

• Archives of Plastic Surgery
• /
• v.48 no.6
• /
• pp.622-629
• /
• 2021

Background Venous malformations (VMs) are the most common type of vascular malformations. Intramuscular venous malformations (IMVMs) are lesions involving the muscles, excluding intramuscular hemangiomas. The purpose of this study was to compare clinical outcomes between patients with IMVMs who were treated with sclerotherapy and those who were treated with surgical excision. Methods Of 492 patients with VMs treated between July 2011 and August 2020 at a single medical center for vascular anomalies, 63 patients diagnosed with IMVM were retrospectively reviewed. Pain, movement limitations, swelling, and quality of life (QOL) were evaluated subjectively, while radiological outcomes were assessed by qualified radiologists at the center. Complication rates were also evaluated, and radiological and clinical examinations were used to determine which treatment group (sclerotherapy or surgical excision) exhibited greater improvement. Results Although there were no significant differences in pain (P=0.471), swelling (P=0.322), or the occurrence of complications (P=0.206) between the two treatment groups, the surgical treatment group exhibited significantly better outcomes with regard to movement limitations (P=0.010), QOL (P=0.013), and radiological outcomes (P=0.017). Moreover, both duplex ultrasonography and magnetic resonance imaging showed greater improvements in clinical outcomes in the surgical excision group than in the sclerotherapy group. Conclusions Although several studies have examined IMVM treatment methods, no clear guidelines for treatment selection have been developed. Based on the results of this study, surgical excision is strongly encouraged for the treatment of IMVMs.