• 대한핵의학회지
• /
• 제29권1호
• /
• pp.15-21
• /
• 1995

To evaluate availability of cerebral radionuclide imaging for diagnosis of brain death, we examined 25 patients with a suspected clinical diagnosis of brain death. 8 patients were studied by $^{99m}Tc$ DTPA and 15 patients were studied by $^{99m}Tc$ HMPAO (Hexamethyl propyleneamine oxime). Seven patients with $^{99m}Tc$ DTPA studies revealed absence of cerebral blood flow and sagittal sinus activity. All of 15 patients with $^{99m}Tc$ HMPAO studies revealed complete absence of cerebral perfusion. The results of the cerebral radionuclide studies of brain death correlated with other clinical conditions, such as intracranial pressure(ICP), EEG, transcranial doppler sonography(TCDS), and neurologic examination. The ICP of 8 patients, who are confirmed by brain death with $^{99m}Tc$ HMPAO study are elevated in all cases. In conclusion, cerebral radionuclide imaging for diagnosis of brain death is available. $^{99m}Tc$ HMPAO imaging is unequivocal, easily interpreted, well reflect the physiologic state of increased ICP, and provides adequate assessment of posterior fossa activity. In addition, the SPECT imaging with $^{99m}Tc$ HMPAO produces more accurate results due to it's superiority of image contrast and proper localization of radiopharmaceutical distribution than conventional planar imaging.

• 대한정형외과학회지
• /
• 제54권4호
• /
• pp.293-301
• /
• 2019

사지와 몸통의 연부조직 종양은 정형외과 의사가 직면할 수 있는 흔한 문제이다. 비록 연부조직 종양은 대부분 양성이지만 정형외과 의사는 양성과 악성 종양을 구별할 수 있는 특징을 알고 있어야 한다. 연부조직 종양의 임상적 특징 및 역학을 이해하게 되면 올바른 진단 및 수술적인 치료를 할 수 있게 된다. 종양의 크기와 깊이는 종양의 진단을 위해 가장 중요한 요소이다. 종양의 감별 진단을 하기 위해서 우선적으로 상세한 병력청취와 자세한 신체 검사가 필요하며, 이후 단순 방사선 촬영, 초음파, 자기공명영상(magnetic resonance imaging), 양전자 방출 단층촬영술(positron emission tomography), 컴퓨터 단층촬영(computed tomography), 뼈 스캔, 혈관 조영술 등의 다양한 영상 촬영법을 사용하여 종양을 진단하고 진단된 종양의 특성을 확인하여야 한다. 특히 초음파 검사는 외래에서도 쉽게 수행할 수 있어 유용하다. 그러나 검사자의 숙련도에 따라 검사 정확도의 차이가 발생할 수 있다는 단점이 있다. 종양의 생검을 통한 조직검사는 종양에 대한 모든 영상 검사를 시행한 후 최종적으로 시행하는 것이 원칙이다. 조직 검사를 시행할 때는 세심한 주의를 기울여야 하며, 최종적인 진단 후에는 치료를 위해 다각적인 접근을 시행하여야 하며 필요한 경우에는 경험 있는 근골격계 종양전문의사에게 의뢰하는 것이 필요하다.

• Imaging Science in Dentistry
• /
• 제52권2호
• /
• pp.155-164
• /
• 2022

Purpose: The aim of this study was to systematically screen the literature for studies reporting cosmetic material in the oral and maxillofacial complex to shed light on the types of cosmetic materials, their radiographic appearance, and possible complications. Materials and Methods: Five electronic databases were reviewed for eligible studies. The general search terms were "cosmetic," "filler," "face," and "radiograph." Demographics, material types, clinical and radiographic presentation, and complications were recorded. Results: Thirty-one studies with 53 cases met the inclusion criteria. The mean age was 52.6±15.4 years with a 4 : 3 female-to-male ratio. The most common material was calcium hydroxyapatite (CaHa) (n=14, 26.4%), found incidentally. The materials were generally located within the upper cheek and zygoma (n=35, 66.0%), radiographically well-defined (n=44, 83%), and had no effects on the surrounding structures (n=27, 50.9%). The internal structure was radiopaque (calcification, hyperdensity) for gold wires, CaHa, bone implants, and secondary calcification or ossification. Outdated cosmetic materials or non-conservative techniques were infiltrative, had effects on the surrounding structures, and presented with clinical signs, symptoms, or complications. Conclusion: Conventional radiography, cone-beam computed tomography, and multi-detector computed tomography are useful to differentiate several cosmetic materials. Their magnetic resonance imaging appearance was highly variable. The infrequent inclusion of cosmetic materials in the differential diagnosis implies that medical and dental specialists may be unfamiliar with the radiographic appearance of these materials in the face.

• 생물정신의학
• /
• 제25권1호
• /
• pp.1-8
• /
• 2018

Insomnia is a common sleep-related symptom which occurs in many populations, however, the neural mechanism underlying insomnia is not yet known. The hyperarousal model explains the neural mechanism of insomnia to some extent, and the frontal cortex dysfunction has been known to be related to primary insomnia. In this review, we discuss studies that applied resting state and/or task-related functional magnetic resonance imaging to demonstrate the deficits/dysfunctions of functional activation and network in primary insomnia. Empirical evidence of the hyperarousal model and proposed relation between the frontal cortex and other brain regions in primary insomnia are examined. Reviewing these studies could provide critical insights regarding the pathophysiology, brain network and cerebral activation in insomnia and the development of novel methodologies for the diagnosis and treatment of insomnia.

• 생물정신의학
• /
• 제28권2호
• /
• pp.23-35
• /
• 2021

Fear conditioning and extinction, which are adaptive processes to learn and avoid potential threats, have essential roles in the pathophysiology of anxiety disorders. Experimental fear conditioning and extinction have been used to identify the mechanism of fear and anxiety in humans. However, the brain-based mechanisms of fear conditioning and extinction are yet to be established. In the current review, we summarized the results of neuroimaging studies that examined the brain changes-functional activity and structures-regarding fear conditioning or extinction in healthy individuals. The functional activity of the amygdala, insula, anterior cingulate gyrus, ventromedial prefrontal cortex, and hippocampus changed dynamically with both fear conditioning and extinction. This review may provide an up-to-date summary that may broaden our understanding of pathophysiological mechanisms of anxiety disorder. In addition, the brain regions that are involved in the fear conditioning and extinction may be considered as potential treatment targets in the future studies.

• 정보보호학회논문지
• /
• 제26권4호
• /
• pp.911-919
• /
• 2016

과거에 비해 현재의 디스크 저장 공간은 비약적으로 증가하고 있으며, 네트워크상에서도 이전과 비교할 수 없는 수많은 데이터들이 처리되고 있다. 이러한 데이터의 대용량화는 앞으로도 계속 될 추세이지만, 그에 비해 포렌식 관점에서 데이터를 이미징 하는 시간을 개선시키기 위한 연구는 부족한 상황이다. 본 논문은 데이터 이미징 시간을 개선시키기 위한 방안으로 전체 이미징 소요시간 중 해시함수에 대한 소요시간을 암호학적 관점에서 살펴보고, 이를 토대로 EWF 파일 이미징 과정에 대한 효율성 개선 방안을 제안한다.

• 대한치과보철학회지
• /
• 제38권3호
• /
• pp.291-309
• /
• 2000

Statement of problem. There were several studies on the effects of irradiation to peri-implant bone tissue. However, no clear biological effect of irradiation on peri-implant bone tissue was reported yet. Purpose. This study compared the effect of irradiation on the surrounding tissue of a HA-coated implant fixture with controls. Material and methods. 6 Steri-Oss implants were implanted into the femur of 6 mongrels. The implanted dogs were divided into three groups and received irradiation. After 1 month, 2months and 4 months healing period, the histologic examination and mobility test and digital radiographic imaging analyses were performed to compare the control and experimental group respectively. Results. The irradiated group showed slower healing than control group in light microscopic observations. The mobility test demonstrated significant less number (Periotest) in control group than that of irradiated groups. The digital radiographic imaging analysis showed that the bone density of irradiated group was higher than control group. Conclusion. Generally, control group showed favorable biological response and less mobility than irradiated group. The conflict result of bone density value were measured by the digital radiographic imaging analysis. The digital radiographic imaging analysis needs more research in future.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• 제18권2호
• /
• pp.144-148
• /
• 2015

Hepatocellular adenomas are a benign, focal, hepatic neoplasm that have been divided into four subtypes according to the genetic and pathological features. The ${\beta}$-catenin activated subtype accounts for 10-15% of all hepatocellular adenomas and specific magnetic resonance imaging features have been defined for different hepatocellular adenomas subtypes. The current study aimed to report the magnetic resonance imaging features of a well differentiated hepatocellular carcinoma that developed on the basis of ${\beta}$-catenin activated hepatocellular adenomas in a child. In this case, atypical diffuse steatosis was determined in the lesion. In the literature, diffuse steatosis, which is defined as a feature of the hepatocyte nuclear factor-$1{\alpha}$-inactivated hepatocellular adenomas subtype, has not been previously reported in any ${\beta}$-catenin activated hepatocellular adenomas case. Interlacing magnetic resonance imaging findings between subtypes show that there are still many mysteries about this topic and larger studies are warranted.

• Fisheries and Aquatic Sciences
• /
• 제14권3호
• /
• pp.218-225
• /
• 2011

Dual frequency identification sonar (DIDSON) is an imaging sonar that has been used for numerous fisheries investigations in a diverse range of freshwater and marine environments. The main purpose of DIDSON is fish counting, fish sizing, and fish behavioral studies. DIDSON records video-quality data, so processing power for handling the vast amount of data with high speed is a priority. Therefore, a semiautomated analysis of DIDSON data for fish counting, sizing, and fish behavior in Echoview (fisheries acoustic data analysis software) was accomplished using testing data collected on the Rakaia River, New Zealand. Using this data, the methods and algorithms for background noise subtraction, image smoothing, target (fish) detection, and conversion to single targets were precisely illustrated. Verification by visualization identified the resulting targets. As a result, not only fish counts but also fish sizing information such as length, thickness, perimeter, compactness, and orientation were obtained. The alpha-beta fish tracking algorithm was employed to extract the speed, change in depth, and the distributed depth relating to fish behavior. Tail-beat pattern was depicted using the maximum intensity of all beams. This methodology can be used as a template and applied to data from BlueView two-dimensional imaging sonar.

• 대한의용생체공학회:의공학회지
• /
• 제20권4호
• /
• pp.503-513
• /
• 1999

본 논문에서는 일반적인 합성구경기법에 대한 통합 모형을 제시하고 수학적인 해석을 통하여 합성구경 기법들에 대한 초음파 빔패턴의 단일 표현식을 유도하였다. 이 결과를 이용하여 기존의 합성구경 기법들에 대한 성능을 분석하고 비교하였으며, 선형주사 영상에 적합한 새로운 합성구경 기법을 제안하였다. 제안된 방법은 모든 영상점에서 양방향 동적 집속이 가능하며, 이를 실제 영상에 적용하여 의료용 초음파 B-모드 영상의 해상도를 획기적으로 개선할 수 있다. 제안된 방법에 의하여 집속된 초음파 빔패턴은 기존의 방식과 비교하여 주엽의 폭이 절반으로 감소하고 측엽의 크기는 유사하다. 컴퓨터 모사실험을 통하여 본 논문의 해석결과와 제안된 합성구경 기법의 타당성을 검증하였다.