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Intramuscular Hematoma on the Psoas Muscle
서준규,양주철,김태완,박관호 대한신경손상학회 2019 Korean Journal of Neurotrauma Vol.15 No.2
Intramuscular hematomas on the psoas muscle are rare and usually occur as a result of trauma, iatrogenic etiology during lumbar surgery, rupture of the aortic aneurysm, and hematologic diseases. The incidence of spontaneous psoas muscle hematomas has slowly increased as a result of using anticoagulation and antiplatelet agents. Magnetic resonance (MR) imaging is a more sensitive option compared to computed tomography (CT) when diagnosing a hematoma. Coronal T2-weighted images are more useful. CT imaging is also useful to establish the rapid diagnosis of hematoma. When a prolonged prothrombin time and international normalized ratio and decrease platelet count are noted, psoas muscle hematomas should be considered, if there was no lesion in the spinal canal. Most hematomas resolve spontaneously without clinical complications if the hematoma is not large or it is not compressing the surrounding important structures, irrespective of cause.
서준규,양주철,Ji Hye Lee,오인호,Tae Wan Kim,Kwan Ho Park 대한신경손상학회 2021 Korean Journal of Neurotrauma Vol.17 No.1
Objective: Subdural hematoma (SDH) primarily occurs in elderly patients. While most patients have good prognosis, some do not. Hematoma recurrence is one of the factors influencing prognosis. Moreover, some characteristic radiological factors may increase the recurrence rate. The aim of this study was to investigate whether the presence of trauma influenced radiological characteristics and hematoma recurrence in SDH patients treated with burr hole trephination. Methods: From January 2012 to December 2014, we selected 83 patients diagnosed with unilateral SDH using computed tomography and/or magnetic resonance imaging. We divided the patients into 2 groups based on the presence of trauma. We compared the 2 groups with multiple parameters, such as patient factors, radiological characteristics, and recurrence rate. Results: Patients who had a prolonged international normalized ratio (INR) were signifcantly more common in the non-traumatic SDH group (22.2%:55.2%, p=0.002). There was no statistical difference in radiological parameters between the 2 groups. The recurrence rate was marginally higher in the non-traumatic SDH group (14.8%:17.2%, p=0.502), but this difference was not statistically signifcant. Conclusion: There were no statistically signifcant differences in the radiological fndings, including brain atrophy, hematoma density, thickness of hematoma, and degree of midline shifing between the 2 groups. The associated trauma history may not influence recurrence. Anticoagulants medication influence INR prolongation, and commonly shown in nontraumatic group, but not statistically. INR prolongation was statistically more common in non-traumatic SDH patients than in traumatic SDH patients. INR prolongation is only a different characteristic between 2 groups.
도파로 어레이 격자를 이용한 광섬유 브래그 스트레인 센서의 반사파장 신호 복원 기술
서준규,김경조,오민철,이상민,김영제,김명현,Seo, Jun-Kyu,Kim, Kyung-Jo,Oh, Min-Cheol,Lee, Sang-Min,Kim, Young-Jae,Kim, Myung-Hyun 한국광학회 2008 한국광학회지 Vol.19 No.1
광섬유 브래그 격자(fiber Bragg grating: FBG)를 이용한 스트레인 센서는 출력 값으로 브래그 반사 파장의 변화를 제공하게 된다. 본 논문에서는 브래그 격자 스트레인 센서에서 출력되는 빛을 도파로 어레이 격자(arrayed waveguide grating: AWG)에 입력시켜서 파장의 변화를 측정하는 방법을 제안한다. FBG에 스트레인이 가해지게 되면 브래그 반사 파장이 이동하게 되어 AWG를 지나서 출력되는 채널별 광 파워가 변하게 되며, 이 값들의 조합으로 구해지는 centroid 값을 계산하면 브래그 반사 파장과 인가된 스트레인 값을 얻을 수 있다. 브래그 격자의 반사 스펙트럼의 대역폭이 centroid 값에 미치는 영향을 고려하여 3-dB 대역폭이 5.4 nm인 chirped FBG를 사용하였으며, 저항 측정방식의 기존 스트레인 센서와 비교하여 오차범위가 2% 이내인 결과를 확인 하였다. FBG 센서를 외팔보에 부착하여 진동에 따른 스트레인 값을 실시간으로 측정한 결과 진동 주파수 17.8 Hz, damping 시상수 0.96 초를 얻을 수 있었다. Fiber-optic strain sensors based on Bragg reflection gratings produce the change of reflection spectrum when an external stress is applied on the sensor. To measure the Bragg reflection wavelength in high speed, an arrayed waveguide grating device is incorporated in this work. By monitoring the output power from each channel of the AWG, the peak wavelength corresponding to the applied strain could be obtained. To enhance the accuracy of the AWG wavelength interrogation system, a chirped fiber Bragg grating with a 3-dB bandwith of 5.4 nm is utilized. The high-speed response of the proposed system is demonstrated by measuring a fast varying strain produced by the damped oscillation of a cantilever. An oscillation frequency of 17.8 Hz and a damping time constant of 0.96 second are obtained in this measurement.