• 한국방사선학회논문지
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• 제17권7호
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• pp.1041-1047
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• 2023

고 해상력 CT에 해당하는 관자뼈 CT는 높은 관전압과 얇은 단면두께 등의 적용으로 스캔 선량이 인접 부위 검사보다 높다. 이에 검사조건 중 재구성 알고리즘을 변화 적용하여 검사 선량을 줄이면서 병변에 대한 민감도가 우수한 알고리즘을 찾아 유의성과 임상 기초자료 제공 가능성을 알아보았다. 그 결과 100 kVp로 관전압을 낮추어 적용 시 선량이 약 35.6% 감소하였고, 100 kVp로 획득한 Raw data에 Definition 알고리즘 적용 시 SNR, CNR이 우수하였으며 다른 알고리즘과 비교 시 통계적으로 유의한 차이를 보였다(p<0.05). 그리고 구조적 유사도를 비교한 결과 SSIM index가 ROI 별 0.776, 0.813, 0.741로 분석되었다. 따라서 관자뼈 CT 스캔에서 알고리즘 변경적용은 CT 검사로 발생하는 선량을 일부 감소시킬 수 있고 임상 기초자료 측면에서 매우 의미가 있다고 생각한다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.1.1-1.4
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• 2016

Background: This study aimed to investigate the distribution and prevalence of intraosseous loop (anastomosis between posterior superior alveolar artery and infraorbital artery) in Koreans detected on computed tomography (CT) images taken prior to sinus augmentation surgery. Methods: From the 177 patients who underwent sinus augmentation with lateral approach at Ewha Womans University Department of Implant Dentistry, 284 CT scans were evaluated. The canal height (CH), ridge height (RH), and canal height from the sinus floor (CHS) were measured on para-axial views at the first premolar, first molar, and second molar. The horizontal positions of the bony canals in the lateral wall were also classified. One-way analysis of variance (ANOVA) and t test were used to estimate the statistical differences (p < 0.05). Results: The intraosseous loops were detected in 92 CT scans (32 %). The mean vertical height of the bony canals from the alveolar crest (CH) was $23.45{\pm}2.81$, $15.92{\pm}2.65$, and $16.61{\pm}2.92mm$ at the second premolar, first molar, and second molar, respectively. In the horizontal positions of the bony canals, intraosseous type was the most predominant. The canal heights more than 15 mm and less than 17 mm were most prevalent (33.7 %) and those under 13 mm were 12.0 %. Conclusions: The radiographic findings in this study could be used to decide the lateral osteotomy line avoiding potential vascular complication. However, only one third of the canals could be detected in CT scans; a precaution should be taken for the possibility of severe bleeding during lateral osteotomy.

• Archives of Plastic Surgery
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• 제33권2호
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• pp.233-236
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• 2006

Merkel cell carcinoma is rare skin malignancy originated from epidermal mechanoreceptor of neural origin. The tumor usually affects older individuals at sun exposed area such as head, neck and extremity. Subclinical involvement of regional lymph node is reported frequently at the time of initial treatment. Thus even asymptomatic patients who present with clinically localized tumor should undergo evaluation with computed tomography and lymphangiography. Positron emission tomography(PET) scans can imaging the metabolic difference of malignant tumors. Increased glucose uptake of malignant tumor cells are detected by PET scanner. PET scans can provide qualitative and quantitative informations about systemic metastasis of tumors. Although there are no data that define the efficacy of PET scans in the initial diagnostic evaluation of head and neck cancer, they could be considered. Current standards of treatment of Merkel cell carcinoma is wide surgical excision and regional lymphadenectomy if there are suspicious lymph nodes. The author reported a patient with Merkel cell carcinoma of cheek. Wide surgical excision and postoperative PET/CT was done for evaluation of regional lymph node and distant metastasis. There were two hot-uptakes in patient's neck, so they were considered as metastatic node, but finally they were proved to be tuberculosis lymphadenitis after excision.

• Journal of Trauma and Injury
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• 제22권1호
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• pp.18-23
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• 2009

Purpose: In this study, we retrospectively investigated the medical records of patients with facial fractures and suspected cranial injuries in order to determine if there was any relationship between various facial fracture patterns and cranial injuries. Methods: Medical records were reviewed to identify patients diagnosed with facial fractures who underwent cranial computed tomography (CT) scans. Records were reviewed for gender, age, injury mechanism, facial fracture pattern, and presence or absence of cranial injuries. Facial fracture patterns were classified as isolated fractures (tripod, zygomatic arch, maxilla, orbit, and mandible), combined fractures, or total fractures. Cranial injuries included skull fractures, traumatic subarachnoid hemorrhages, subdural hemorrhages, epidural hemorrhages, and contusional hemorrhages. All cranial injuries were established by using cranial CT scans, and these kinds of cranial injuries were defined radiologically-proven cranial injuries (RPCIs). We evaluated the relationship between each pattern of facial fractures and the incidence of RPCIs. Results: Of 132 eligible patients with facial fractures who underwent cranial CT scans, a total of 27 (20.5%) patients had RPCIs associated with facial fractures. Falls and slips were the most common causes of the fractures (31.8%), followed by assaults and motor vehicle accidents (MVAs). One hundred one (76.5%) patients had isolated facial fractures, and 31 (23.5%) patients had combined facial fractures. Fractures were found most commonly in the orbital and maxillary bones. Patients with isolated maxillary fractures had a lower incidence of RPCIs than those with total mandibular fractures. RPCIs frequently accompanied combined facial fractures. Conclusion: Combined facial fractures had a significant positive correlation with RPCIs. This means that facial fractures caused by stronger or multidirectional external force are likely to be accompanied by cranial injuries.

• Radiation Oncology Journal
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• 제1권1호
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• pp.47-53
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• 1983

CT scans obtained on 15 patients of head and neck malignant tumors were evaluated for their utility in ratiotherapy treatment planning. To evaluate the advantage of incorporating CT scans in radiotherapy treatment planning of head and neck malignant tumors, the dose distributions of treatment plan with and without CT scan were compared in 15 patients. And then the dose distributions of the first and second treatment plan were compared. 1. Tumor extend and localization were clearly delineated on CT scan in 12 of 15 cases (80%), suggestive in 2 (13.3%), and not seen in only one (6.7%) which had been in the postoperative state. 2. Tumor coverage after CT scan was adequate in 14 of 15 cases (93.3%) and not in only one. In one case of inadequate tumor coverage the target volume lay inside the field but reached within 0.5cm of the field margin (marginal miss). 3. The volume of normal tissue irradiated was reduced after CT scan in 12 of 15 cases (80%), increased in 1 (6.7%) and not changed in 2 (13.3%). 4. We could maximize the local control of disease and minimize unnecessary morbidity by delineating the location and extent of tumor and normal tissue with CT for treatment plannings.

• 한국정보과학회논문지:소프트웨어및응용
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• 제37권1호
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• pp.9-18
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• 2010

본 논문에서는 호기와 흡기에 촬영된 흉부 CT 영상간 폐 영상정합을 위해 데몬 알고리즘을 이용한 비강체 정합 방법을 제안한다. 먼저 두 영상에 어파인 변환을 적용하여 폐를 전역적으로 정렬한 후, 데몬 알고리즘에 기반한 비강체 정합 방법을 적용하여 지역적으로 변형시킨다. 데몬 힘의 계산을 위해 기준영상의 기울기 정보 뿐 아니라 부유영상의 기울기 정보를 함께 사용하여 기준영상의 기울기가 약한 부분에서 빠른 수렴을 돕는다. 활성-셀 기반 데몬 알고리즘은 두 영상 간 정합도가 높은 셀에서의 불필요한 변위 계산을 방지함으로써 정합 과정을 가속화시키고 변형 접힘 현상의 확률을 줄여주는 역할을 한다. 제안방법의 성능을 평가하기 위해 기준 기울기 힘을 사용한 방법과 부유 기울기 힘을 함께 사용한 방법을 비교하고, 활성-셀을 사용한 방법과 사용하지 않은 방법을 비교하였다. 실험 결과는 제안 방법이 변형이 큰 폐를 정확하게 정합하며 수행시간을 감소시킴을 보여준다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제29권11호
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• pp.803-808
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• 2002

본 논문은 복부 컴퓨터단층촬영(CT) 영상에서의 자동화된 신장 및 신장암 추출에 관한 연구를 수행하였다. 필름으로 보관된 복부 CT 영상을 디지털화하여 영상분석을 수행하였으며, 명암값에 의한 임계값(Gray-Level Thresholding) 처리 기법을 사용하여 신장만을 분리하였다. 신장암의 샘플영상에 대한 텍스쳐(Texture)분석 결과를 토대로, 대표적인 통계적 모멘트 값인 평균 및 표준 편차값을 동질성 시험 기준으로 삼아 신장암의 SEED를 선택하였다. 선택된 SEED의 중앙 픽셀을 시작점으로 하여, 명암값을 동질성 시험기준으로 사용한 영역확장(Region Growing) 방법을 적용하여 신장암을 추출하였다. GE사의 Hispeed Advantage CT 스캐너를 사용하여 촬영된 9개의 예, 총 113매 영상을 Lumisys LS-40 필름 디지타이저로 디지털화 하여 적용한 결과, 85%의 신장암 추출 민감도를 가진다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권4호
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• pp.213-220
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• 2009

Purpose: The present study was aimed to examine the usefulness of 18F-FDG PET/CT in the evaluation of cervical lymph node metastasis in patients with oral cancer. Materials and methods: Twenty-two patients who underwent neck dissection to treat oral cancer were subjected for examination. The cervical node metastasis was evaluated by means of clinical examination, CT scan, PET, and histologic examination. By comparing the results of each examination modality with those of histologic examination, it's sensitivity, specificity, positive predictive value, and negative predictive value were determined. Results: The oral cancer was more frequent in males with a ratio of 2.14:1. The sixth decade showed the highest incidence in age distribution with mean of $56{\pm}16$. Histologic findings showed that squamous cell carcinoma was the most common (15 patients), and mucoepidermoid carcinoma (3), malignant melanoma (2), and adenoid cystic carcinoma and ghost cell odontogenic carcinoma (1 each), in order. In most cases, wide surgical excision of the primary cancer and neck dissection was performed, followed by reconstruction with free flaps when necessary. When comparing the results of each examination modality with those of the histologic examination, clinical examination showed sensitivity, specificity, positive predictive value, and negative predictive value at 11%, 85%, 33%, and 58%, respectively. CT scans showed at 67%, 77%, 67%, and 77%, while $^{18}F$-FDG PET/CT at 78%, 77%, 70%, and 83%, respectively. Conclusions: These results suggest that PET is more useful, compared with clinical examination and CT scans, in the evaluation of cervical lymph node metastasis in patients with oral cancer.

• 디지털융복합연구
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• 제12권10호
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• pp.425-431
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• 2014

본 연구는 ATOM Phantom을 이용하여 선량, 화질을 비교 분석 하여 Volume mode의 유용성 밝혀 소아 CT 검사에 적극적으로 사용하기 위함이다. Helical mode Noise와 Volume mode의 Noise, HU, SNR은 p>0.05 이므로 통계적으로 유이한 차이가 없음을 알 수 있었다. 각 부위별 선량값은 모두 p>0.05 이므로 통계적 유이한 차이가 없었으나 DLP값이 Helical mode보다 Volume mode가 더 낮게 측정되었다. 유효선량 역시 Volume mode가 Helical mode 보다 낮음을 알 수 있었다. 정성적 분석에서는 Mode에 따른 조건 별로 각각 Helical: 2.6, 3.3, 4.36 Volume: 2.8, 3.64, 4.44, Mode별 Follow up 영상평가 결과로는 Helical mode가 3.8 Volume mode가 3.83점으로 큰 차이가 없는 것으로 나타났다. 5세 이하의 소아 CT검사에 있어서 640-MDCT Volume scan이 Helical mode와 비교해 낮은 선량으로 영상의 질이 큰 차이가 없기에 소아 CT 검사에는 유용 하다고 생각된다.

• 한국방사선학회논문지
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• 제13권7호
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• pp.933-939
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• 2019

MDCT에서 인체등가형 흉부팬텀과 유리선량계를 이용하여 고해상력 및 저선량 CT로 검사하여 영상의 평가 및 흡수선량 및 유효선량을 측정하여 임상 기초자료를 제공하는데 목표를 두고자한다. 인체등가형 흉부팬텀내부에 유리선량계를 삽입하여 조직선량을 측정하였다. 64-slice CT system (SOMATOM Sensation 64, Siemens AG, Forchheim, Germany)과 CARE Dose 4D를 이용하였고, 고해상력 CT에서의 파라메터는 관전압 120 kVp, Eff. mAs 104, scan time 7.93 sec, slice 1.0 mm (Acq. 64×0.6 mm), convolution kernel (B60f sharp)의 스캔 파라메터가 사용되었고, 저선량 CT는 120 kVp, Eff. mAs 15, scan time 7.41 sec, slice 3.0 mm (Acq. 64×0.6 mm), convolution kernel B50f medium sharp의 스캔하였다. 인체등가형 흉부팬텀을 이용하여 스캔에 따른 CTDIvol은 고해상력 CT에서 8.01 mGy, 저선량 CT는 1.18 mGy로 측정되었다. 저선량 CT 검사는 고해상력 CT 검사에 비해 흡수선량이 85.49%가 감소하였고 영상의 차이는 없어 임상에서 유용하게 적용할 수 있다.