• 한국의학물리학회지:의학물리
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• 제19권2호
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• pp.120-124
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• 2008

본 연구에서는 영상 기반 방사선 치료기기의 영상 QA를 위한 필요한 추가적인 요소를 포함시킨 QA 팬텀 시제품을 개발하였다. 개발된 팬텀은 크게 영상 질 평가 부분과 정합 정확도 평가 부분의 두 가지로 이루어져 있다. 영상 질 평가를 위해 CT number 선형성과 공간 해상도 평가가 가능하게 설계되었고, 정합 정확도 평가를 위하여 간단한 이동 및 회전조절이 가능하게 설계되었다. 제작된 팬텀의 영상은 일반 CT와 Tomotherapy의 MVCT에서 획득되었고, 두 영상 모두 해상도 평가 기준을 충족하였다. 이 팬텀은 일간 영상 QA를 위한 간단하고, 효율적이며, 그리고 영상 정합 평가의 새로운 개념을 제시했다는 데에 큰 의의가 있다.

• 한국의학물리학회지:의학물리
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• 제3권1호
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• pp.53-62
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• 1992

최근 두개부 종양의 방사성물질의 자입과 방사선입체조사에 의한 뇌수술이 개발되어 의료계 에 많은 관심을 끌고 있다. 또한 방사선수술등은 비관혈적인 체외조사이므로 뇌정위수술용 좌표계의 전산화단층촬영을 이용한 표적중심결정이 매우 중요하다. 현재 알려진 방법은 뇌정위수술용좌표계의 전산화단층찰영에 대한 직교성하에서 비교적 정확하게 표적의 위치를 결정하게 되나, 임상현장에서 직교성유지는 실제 어려운 실정이다. 이에 필자들은 임의의 비직교성 스켄하에서 정확한 표적좌표를 얻기위한 알고리즘을 사용하였으며, 표적오차는 평균 0.02$\pm$0.3mm를 보였다.

• Journal of Yeungnam Medical Science
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• 제21권1호
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• pp.74-81
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• 2004

서론: 면역기능 정상인 환자에서 폐효모균증의 전산화단층촬영상(CT)의 소견을 알아보고자 하였다. 대상 및 방법: 조직학적으로 확진된 25명의 폐효모균증 황자를 대상으로 하였다. 13명은 남자였고 12명은 여자였으며, 평균연령은 53.7세 였다. 주 증상은 기침, 가래, 및 호흡곤란이었고, 12명의 환자에서는 증상이 없었다. 결과: 결절 혹은 다수결절(10명 40%)을 보이거나 분절 혹은 이분절성 폐경결(9명 36%)이 가장 흔한 소견이었다. 주 침범부위는 하엽(57%) 늑막하부(92%)였다. 폐경결 내부에 공기관지 음영(79%)을 보이며 용적감소를 보인 경우(71%)가 흔하였다. 간질비후 음영(44%) 및 공동형성(44%)도 자주 보였으나, 임파절 종대(8%) 및 늑막삼출(4%)은 드문 소견이었다. 결론: 폐 하엽 늑막하 부위에 다수의 결절 혹은 폐경결성 병변이 면역기능 정상인 환자에서 폐효모균증의 가장 흔한 소견이었다.

• Journal of Korean Neurosurgical Society
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• 제56권4호
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• pp.330-333
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• 2014

Objective : To identify the accuracy and efficiency of the computed tomographic (CT)-based navigation system on upper cervical instrumentation, particularly C1 lateral mass and C2 pedicle screw fixation compared to previous reports. Methods : Between May 2005 and March 2014, 25 patients underwent upper cervical instrumentation via a CT-based navigation system. Seven patients were excluded, while 18 patients were involved. There were 13 males and five females; resulting in four degenerative cervical diseases and 14 trauma cases. A CT-based navigation system and lateral fluoroscopy were used during the screw instrumentation procedure. Among the 58 screws inserted as C1-2 screws fixation, their precise positions were evaluated by postoperative CT scans and classified into three categories : in-pedicle, non-critical breach, and critical breach. Results : Postoperatively, the precise positions of the C1-2 screws fixation were 81.1% (47/58), and 8.6% (5/58) were of non-critical breach, while 10.3% (6/58) were of critical breach. Most (5/6, 83.3%) of the critical breaches and all of non-critical breaches were observed in the C2 pedicle screws and there was only one case of a critical breach among the C1 lateral mass screws. There were three complications (two vertebral artery occlusions and a deep wound infection), but no postoperative instrument-related neurological deteriorations were seen, even in the critical breach cases. Conclusion : Although CT-based navigation systems can result in a more precise procedure, there are still some problems at the upper cervical spine levels, where the anatomy is highly variable. Even though there were no catastrophic complications, more experience are needed for safer procedure.

• 대한방사선기술학회지:방사선기술과학
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• 제32권3호
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• pp.307-312
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• 2009

CT 검사에서 수정체 차폐용 비스무트(bismuth)를 사용하여 수정체 선량의 감소효과를 유리선량계로 측정하여 비스무트 차폐효과 및 영상을 평가하였다. 안구 및 두부 CT 검사에서 차폐용 비스무트를 사용하여 수정체 선량의 감소와 차폐 효과를 평가하기 위해 인체모형 팬텀으로 유리선량계를 이용하여 수정체 선량을 평가하였다. 유리선량계를 이용하여 비스무트를 사용하기 전의 평균 선량은 21.54 mGy이었고, 사용 후의 선량은 10.46 mGy로 51.3%의 선량 감소효과가 있다. 차폐용 비스무트를 사용한 안구 64 MDCT 촬영에서 선량감소 효과가 있어 수정체를 포함한 안구 CT 스캔에서는 비스무트를 사용하여 검사하도록 권고한다.

• Journal of Trauma and Injury
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• 제23권2호
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• pp.142-150
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• 2010

Purpose: In this study, patients in whom two computed tomography (CT) scans had been obtained within 24 hours of injury were analyzed to determine the incidence, risk factors and clinical significance of a progressive intracerebral hematoma (PIH). Methods: Participants were 182 patients with a traumatic intracerebral hematoma and contusion who underwent a repeat CT scan within 24 hours of injury. Univarite and multivariate statistics were used to define growth (volume increase) and to examine the relationship between the risk factors and hemorrhage expansion. Results: Fifty-four percent of the patients experienced progression in the size of the lesion in the initial 24 hours postinjury. A PIH was independently associated with worsened Glasgow coma scale (GCS) score (2.99, 1.04~8.60), the presence of subarachnoid hemorrhage (6.29, 2.48~16.00), the presence of a subdural hematoma (6.18, 2.13~17.98), the presence of an epidural hematoma (5.73, 1.18~27.76), and the presence of a basal cistern effacement (10.93, 1.19~99.57). Conclusion: For patients undergoing scanning within 2 hours of injury, the rate of PIH approaches 61%. Early repeated CT scanning is indicated in patients with a nonsurgically-treated hemorrhage revealed on the first CT scan. Worsened GCS score, significant hematoma growth and effacement of the basal cisterns on the initial CT scan are powerful predictors of which patients will require surgery. These findings should be important factors in understanding and managing of PIH.

• Tuberculosis and Respiratory Diseases
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• 제83권4호
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• pp.283-288
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• 2020

Background: Latent tuberculosis (TB) infection among TB contacts is diagnosed using plain chest radiography and interferon-gamma release assays (IGRAs). However, plain chest radiographs often miss active TB, and the results of IGRA could fluctuate over time. The purpose of this study was to elucidate changes in the results of the serial IGRAs and in the findings of the serial submillisievert chest computed tomography (CT) scans among the close contacts of active pulmonary TB patients. Methods: Patients age 20 or older with active pulmonary TB and their close contacts were invited to participate in this study. Two types of IGRA (QuantiFERON-TB Gold In-Tube assay [QFT-GIT] and the T-SPOT.TB test [T-SPOT]) and submillisievert chest CT scanning were performed at baseline and at 3 and 12 months after enrollment. Results: In total, 19 close contacts participated in this study. One was diagnosed with active pulmonary TB and was excluded from further analysis. At baseline, four of 18 contacts (22.2%) showed positive results for QFT-GIT and T-SPOT; there were no discordant results. During the follow-up, transient and permanent positive or negative conversions and discordant results between the two types of IGRAs were observed in some patients. Among the 17 contacts who underwent submillisievert chest CT scanning, calcified nodules were identified in seven (41.2%), noncalcified nodules in 14 (82.4%), and bronchiectasis in four (23.5%). Some nodules disappeared over time. Conclusion: The results of the QFT-GIT and T-SPOT assays and the CT images may change during 1 year of observation of close contacts of the active TB patients.

• Journal of Trauma and Injury
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• 제21권1호
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• pp.15-21
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• 2008

Purpose: National Emergency X-Radiography Utilization Study (NEXUS) criteria and the Canadian Cervical Spine rule (CCR) are commonly used in cervical trauma patients to determine whether a plain cervical X-ray should be performed. However, plain cervical X-rays are so inaccurate that cervical spine computed tomography (CT) is often considered as a screening test. We studied the usefulness of the NEXUS criteria and the CCR for determining the need for a CT evaluation in the emergency department (ED). Methods: This prospective observational study was conducted from January 2007 to March 2008. Plain X-ray and CT scans of the cervical spine were performed on blunt trauma patients with neck pain. The relevancy of CT was examined using the NEXUS criteria and the CCR. Sensitivity, specificity, positive predicted value, and negative predicted value analyses were performed to diagnose the cervical spine injury. Results: During the study period, 284 patients were enrolled in this study. The sensitivity, specificity, positive predicted value, and negative predicted value of the NEXUS criteria were 87.5%, 1.1%, 5.0%, and 60.0% respectively, while those of the CCR were 87.5%, 8.2%, 5.3%, and 91.6%. There were two missed fracture cases when the NEXUS criteria and the CCR were applied independently, however, no cases were missed when both were applied. Conclusion: This study suggests the NEXUS and the CCR in combination can be used as a guide to CT evaluation for cervical spine injury in the ED.

• Clinics in Shoulder and Elbow
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• 제21권4호
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• pp.186-191
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• 2018

Background: To determine the normal range of humeral head positioning on magnetic resonance imaging (MRI). Methods: We selected normal subjects (64 patients; group A) to study the normal range of humeral head positioning on the glenoid by MRI measurements. To compare the MRI measurement method with the computed tomography (CT), we selected group B (70 patients) who underwent both MRI and CT. We measured the humeral-scapular alignment (HSA) and the humeral-glenoid alignment (HGA). Results: The HSA in the control group was $1.47{\pm}1.05mm$, and the HGA with and without reconstruction were $1.15{\pm}0.65mm$ and $1.03{\pm}0.59mm$, respectively, on MRI. In the test group, HSA was $2.67{\pm}1.47mm$ and HGA with and without reconstruction was $1.58{\pm}1.16mm$ and $1.49{\pm}1.08mm$, on MRI. On CT, the HSA was $1.72{\pm}1.01mm$, and HGA with and without reconstruction were $1.54{\pm}0.96mm$ and $1.59{\pm}0.93mm$, respectively. HSA was significantly different according to image modality (p=0.0006), but HGA was not significantly different regardless of reconstruction (p=0.8836 and 0.9234). Conclusions: Although additional CT scans can be taken to measure decentering in patients with rotator cuff tears, reliable measurements can be obtained with MRI alone. When using MRI, it is better to use HGA, which is a more reliable measurement value based on the comparison with CT measurement (study design: Study of Diagnostic Test; Level of evidence II).

• Journal of Periodontal and Implant Science
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• 제49권2호
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• pp.127-135
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• 2019

Purpose: The aim of this study was to evaluate the computed tomography (CT) imaging findings and clinical symptoms of patients who complained of neurosensory disturbances after mandibular implant surgery, and to investigate the relationships of these parameters with the prognosis for recovery. Methods: CT scans were reviewed in 56 patients with nerve disturbance after mandibular implant surgery. Two oral radiologists classified the imaging findings into intrusion, contact, close, and separate groups according to the distance from the inferior border of the implant to the roof of the mandibular canal (MC). The symptoms of 56 patients were classified into 8 groups and the frequency of each group was investigated. Patients were categorized according to symptom improvement into no recovery and recovery groups, and the relationships of recovery with the CT classification and specific symptom groups were analyzed. Results: Thirty-eight of the 56 nerve disturbance cases showed improvement. The close and separate groups in the CT classification had a strong tendency for recovery (90.9% and 81.8%, respectively) (P<0.05). Although the lowest recovery rate was found in the intrusion group, it was non-negligible, at 50%. The 6 patients with a worm crawling feeling all improved, while the 8 cases with a tightening sensation showed the lowest recovery rate, at 12.5%, and the symptom of a tightening sensation occurred only in the intrusion and contact groups. Conclusions: The closer the implant fixture was to the MC on CT images, the less likely the patient was to recover. Regarding paresthesia symptoms, while a worm crawling feeling is thought to be a predictor of recovery, a tightening sensation appeared to be associated with a lower recovery rate.