악교정 수술에서 모의 조종된 3차원 전산화 단층촬영상의 응용

김형돈,이경상,유선국,박창서 大韓口腔顎顔面 放射線學會 1998 Imaging Science in Dentistry Vol.28 No.2

In orthodontics and orthognathic surgery, cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery, too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipments and because of its expenses and amount of exposure to radiation, limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram, pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms, and for validation of new method, in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery, computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of dry skull that position of mandible was displaced, range of displacement between computer-simulated three dimensional images and actual postoperative three dimensional images in co-ordinates values was from -1.8 mm to 1.8 mm and 94% in displacement of all co-ordinates values was from -1.0 mm to 1.0 mm and no significant difference between computer-simulated three dimensional images and actual postoperative three dimensional images was noticed(p>0.05). 2. In four cases of orthognathic surgery patients, range of displacement between computer-simulated three dimensional images and actual postoperative three dimensional images in coordinates values was from -6.7 mm to 7.7 mm and 90% in displacement of all co-ordinates values was from -4.0 to 4.0 mm and no significant difference between computer-simulated three dimensional images and actual postoperative three dimensional images was noticed(p>0.05). Conclusively, computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms. Therefore, potentiality that can construct postoperative three dimensional image without three dimensional computed tomography after surgery was presented.

Application of Computer-Aided Diagnosis for the Differential Diagnosis of Fatty Liver in Computed Tomography Image

Hyong-Hu Park(박형후),Jin-Soo Lee(이진수) 한국방사선학회 2016 한국방사선학회 논문지 Vol.10 No.6

본 연구는 복부 전산화단층촬영 영상을 이용하여 지방간환자의 영상을 질감특징분석과 ROC curve 분석을 하였으며, 컴퓨터보조진단시스템의 구현을 위한 실험적인 선형 연구로서 전산화단층촬영 영상에서 지방간의 객관적이고 신뢰성 있는 진단 정보를 의사에게 제공하고자 하였다. 실험은 정상 및 지방간 복부 전산화단층촬영 영상을 실험영상으로 하여 설정된 구역에 대한 wavelet 변환을 거쳐 질감의 특징값을 나타내는 6가지 파라미터로 통계적 분석 결과를 나타내었다. 그 결과 엔트로피, 평균밝기, 왜곡도는 90% 이상의 비교적 높은 인식률을 보였고, 대조도, 평탄도, 균일도는 약 70% 정도로 비교적 낮은 인식률을 나타내었다. ROC curve를 이용한 분석에서 6가지의 파라미터 모두 0.900(p=0.0001)이상을 나타내어 질환인식에 의미가 있는 결과를 나타내었다. 또한 6가지 파라미터에서 질환 예측을 위한 cut-off 값을 결정하였다. 이러한 결과는 향후 복부 전산화단층촬영 영상에서 질환 자동검출 및 최종진단의 예비 진단 자료로서 적용 가능할 것이다. In this study, we are using a computer tomography image of the abdomen, as an experimental linear research for the image of the fatty liver patients texture features analysis and computer-aided diagnosis system of implementation using the ROC curve analysis, from the computer tomography image. We tried to provide an objective and reliable diagnostic information of fatty liver to the doctor. Experiments are usually a fatty liver, via the wavelet transform of the abdominal computed tomography images are configured with the experimental image section, shows the results of statistical analysis on six parameters indicating a feature value of the texture. As a result, the entropy, average luminance, strain rate is shown a relatively high recognition rate of 90% or more, the control also, flatness, uniformity showed relatively low recognition rate of about 70%. ROC curve analysis of six parameters are all shown to 0.900 (p = 0.0001) or more, showed meaningful results in the recognition of the disease. Also, to determine the cut-off value for the prediction of disease six parameters. These results are applicable from future abdominal computed tomography images as a preliminary diagnostic article of diseases automatic detection and eventual diagnosis.

Ovarian Masses: Is Multi-detector Computed Tomography a Reliable Imaging Modality?

Khattak, Yasir Jamil,Hafeez, Saima,Alam, Tariq,Beg, Madiha,Awais, Mohammad,Masroor, Imrana Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

Background: Ovarian cancer continues to pose a major challenge to physicians and radiologists. It is the third most common gynecologic malignancy and estimated to be fifth leading cancer cause of death in women, constituting 23% of all gynecological malignancies. Multi-detector computed tomography (MDCT) appears to offer an excellent modality in diagnosing ovarian cancer based on combination of its availability, meticulous technique, efficacy and familiarity of radiologists and physicians. The aim of this study was to compute sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of 64-slice MDCT in classifying ovarian masses; 95% confidence intervals were reported. Materials and Methods: We prospectively designed a cross-sectional analytical study to collect data from July 2010 to August 2011 from a tertiary care hospital in Karachi, Pakistan. A sample of 105 women aged between 15-80 years referred for 64-MDCT of abdomen and pelvis with clinical suspicion of malignant ovarian cancer, irrespective of stage of disease, were enrolled by non-probability purposive sampling. All patients who were already known cases of histologically proven ovarian carcinoma and having some contraindication to radiation or iodinated contrast media were excluded. Results: Our prospective study reports sensitivity, specificity; positive and negative predictive values with 95%CI and accuracy were computed. Kappa was calculated to report agreement among the two radiologists. For reader A, MDCT was found to have 92% (0.83, 0.97) sensitivity and 86.7% (0.68, 0.96) specificity, while PPV and NPV were 94.5% (0.86, 0.98) and 86.7% (0.63, 0.92), respectively. Accuracy reported by reader A was 90.5%. For reader B, sensitivity, specificity, PPV and NPV were 94.6% (0.86, 0.98) 90% (0.72, 0.97) 96% (0.88, 0.99) and 87.1% (0.69, 0.95) respectively. Accuracy computed by reader B was 93.3%. Excellent agreement was found between the two radiologists with a significant kappa value of 0.887. Conclusion: Based on our study results, we conclude MDCT is a reliable imaging modality in diagnosis of ovarian masses accurately with insignificant interobserver variability.

폐종양과 폐암의 병기결정에 대한 양전자단층촬영(PET)의 유용성-전산화단층촬영(CT)과의 비교-

김오곤,조중행,성숙환 대한흉부외과학회 2003 Journal of Chest Surgery (J Chest Surg) Vol.36 No.2

배경: 흉부 전산화 단층촬영(CT)의 폐암 진단율의 한계로 인하여 최근 폐암에 대한 진단과 병기결정에 양전자단층촬영(PET)이 유용한 것으로 알려져 있다. 이에 우리나라 폐암 환자에서 진단 및 병기 결정에 전산화 단층촬영과 양전자단층촬영의 진단율의 차이점과 유용성을 비교하고자 하였다. 대상 및 방법: 1998년 6월부터 1999년 12월까지 흉부 X-선 촬영과 CT에서 폐암이 의심되거나 진단된 55명에서, 타 장기에서 폐로 전이된 9명과 폐암수술후 재발된 5명을 제외한 41명을 대상으로 수술전 CT와 PET 소견과 종격동경이나 개흉술로 확진된 조직병리 소견을 비교하였다. 결과: 41명 대상환자 중 폐종양의 조직학적 진단은 악성병변이 35례(편평세포암 19례, 선암 14례, 선편평세포암 2례)였고, 양성병변은 6례였다. 폐종양의 악성여부에 대한 CT와 PET 두가지 검사의 민감도, 특이도, 정확도는 같았으며 각각 100%, 50%, 92.7% 였다. 최종적인 병리적 림프절군 병기는 N0-N1 31례, N2 8례, N3 2례 였다. 림프절군 병기가 일치하는 경우는 CT가 31례, PET가 28례 였고, CT와 PET의 각각 6례에서 병리학적 림프절 병기보다 낮게 평가되었고, CT의 4례, PET의 7례에서 병기보다 높게 평가되었다. 조직검사가 가능했던 108개의 종격동 림프절군 중 18개 림프절군에서 악성으로 나왔고, 종격동 림프절군 침범여부에 대한 CT와 PET의 민감도, 특이도, 정확도는 각각 39.8%, 93.3%, 84.3% 와 61.1%, 90.0%, 85.2% 였다. 종격동 림프절군에 대한 CT와 PET 검사를 종합하여 같이 분석하였을 때 민감도 77.8%, 특이도 93.3%, 정확도 90.7%이었다. 결론: 폐종양과 림프절군의 병기 설정에 있어 PET검사는 CT와 비교하여 비슷한 유용성이 있는 검사로 사료되며, CT와 PET 두 검사를 같이 시행하여 검토할 때 정확도를 높일 수 있다고 여겨진다. 24.Kernstine KH, McLaughlin KA, Menda Y, Rossi NP, et al. Can FDG-PET reduce the need for mediastinoscopy in potentially resectable nonsmall cell lung cancer? Ann Thorac Surg 2002;73:394-402 25.Dhital K, Saunders CAB, Seed PT, O'Doherty MJ, Dussek J. [18F]Fluorodeoxyglucose positron emission tomography and its prognostic value in lung cancer. Eur J Cardiothorac Surg 2000;18:425-8 Efficacy of Positron Emission Tomography in Diagnosing Pulmonary Tumor and Staging of Lung Cancer: Comparing to Computed Tomography

나선형 고해상도 전산화 단층촬영 영상을 이용한 측두골의 3차원 컴퓨터 영상재건:측두골의 해부 및 임상적 응용

전범조,송선화,이동희,조주은,천병준,조광재,여상원 대한이비인후과학회 2004 대한이비인후과학회지 두경부외과학 Vol.47 No.5

Background and Objectives:The intricate anatomy of the temporal bone has always been dificult to visualize. In this regard, the advantages of computer-asisted reconstruction of temporal bone based on image data from computed tomography (CT) are (3D) reconstruction of computed tomography in determining the anatomy and topographic relationship of various important structures. Subjects and Method:For 40 ears of 20 patients with various otological diseases, 3D reconstruction based on image data from spiral high-resolution CT was performed by segmentation, volume-rendering and surface-rendering algorithm on a personal computer. The scanning was caried out in axial plane with technical factors of 140 kV, 100 mAs, 1 m thickness, and 1 second scanning time. A software (VworksTM ) was used for image processing. Results:We were able to demonstrate the 3D display of the midle and iner ear structures. The computer-assisted measurement of reconstructed structures demonstrated the anatomic details comprehensively, which improved the surgeons understanding of their spatial relationship, and provided many details that could not be easily measured in vivo. Conclusion:The 3D reconstruction of temporal bone CT can be useful in demonstrating ecessary to confirm the correlation betwen 3D reconstructed images and histologic sections through the validation study.

전산화 단층 촬영에서 소프트웨어를 이용한 소폐결절 모형 부피 측정의 정확성 평가

도경현,구진모,이경원,임정기,Do, Gyeong-Hyeon,Gu, Jin-Mo,Lee, Gyeong-Won,Im, Jeong-Gi 대한영상의학회 2004 대한영상의학회지 Vol.50 No.2

목적: 소폐결절 부피를 자동으로 계산할 수 있는 소프트웨어의 임상 적용 가능성을 알아보기 위하여 여러 가지의 소폐결절 모형을 제작하고 측정된 부피의 정확성을 평가하고자 하였다. 대상과 방법: 여러 가지의 실제 부피를 알고 있는 결절 모형을 제작한 후 다중검출기 전산화 단층 촬영으로 결절의 영상을 얻었다. 이 영상을 3차원적으로 재구성한 후 부피 측정 소프트웨어(Rapidiaⓡ, 3D-Med, Seoul, Korea)를 이용하여 측정한 부피와 실제 부피를 비교하여 정확도를 평가하였다. 결과: 지름 1 cm 미만의 소폐결절의 부피는 -200, -400, -600 HU에서 각각 17.3, 2.9, 11.5(%)로 -400 HU에서 가장 오차가 적었으며 유의한 상관 관계를 보였다(r=0.96, p < 0.001). 석회화를 포함한 결절의 경우 각각의 비교 오차는 10.9, 5.3, 16.5 %로 -400 HU에서 오차가 가장 적었으며 유의한 상관 관계를 보였다(r=1.03, p < 0.001). 결절의 주위에 혈관이 인접한 경우에는 비교 오차가 각각 4.6, 16.3, 31.2 %였고 -200 HU에서 오차가 가장 적었으며 유의한 상관 관계를 보였다(r=1.1, p < 0.001). 단순 폐결절의 경우 정확한 부피 측정이 가능하였으며 석회화가 동반되거나 혈관과 인접한 경우라도 역치를 조정하면 정확도가 증가하였다. 결론: 여러 가지 폐결절 모형으로 자동적인 알고리듬에 의한 부피 측정의 정확도의 평가가 가능하였다. Window setting에 관계없이 항상 같은 역치 하에서는 결절의 부피는 일정하게 측정되었다. Purpose: To determine the accuracy of automated computer aided volumetry for simulated small pulmonary nodules at computed tomography using various types of phantoms Materials and Methods: Three sets of synthetic nodules (small, calcified and those adjacent to vessels) were studied. The volume of the nodules in each set was already known, and using multi-slice CT, volumetric data for each nodule was acquired from the three-dimensional reconstructed image. The volume was calculated by applying three different threshold values using Rapidiaⓡ software (3D-Med, Seoul, Korea). Results: Relative errors in the measured volume of synthetic pulmonary nodules were 17.3, 2.9, and 11.5% at -200, -400, and -600 HU, respectively, and there was good correlation between true volume and measured volume at -400 HU (r=0.96, p<0.001). For calcified nodules, relative errors in measured volume were 10.9, 5.3, and 16.5% at -200, -400, and -600 HU, respectively, and there was good correlation between true volume and measured volume at -400 HU (r=1.03, p<0.001). In cases involving synthetic nodules adjacent to vessels, relative errors were 4.6, 16.3, and 31.2 % at -200, -400, and -600 HU, respectively. There was good correlation between true volume and measured volume at -200 HU (r=1.1, p<0.001). Conclusion: Using computer-aided volumetry, the measured volumes of synthetic nodules correlated closely with their true volume. Measured volumes were the same at each threshold level, regardless of window setting.

Accuracy of computer-aided template-guided oral implant placement: a prospective clinical study

Beretta, Mario,Poli, Pier Paolo,Maiorana, Carlo Korean Academy of Periodontology 2014 Journal of Periodontal & Implant Science Vol.44 No.4

Purpose: The aim of the present study was to evaluate the in vivo accuracy of flapless, computer-aided implant placement by comparing the three-dimensional (3D) position of planned and placed implants through an analysis of linear and angular deviations. Methods: Implant position was virtually planned using 3D planning software based on the functional and aesthetic requirements of the final restorations. Computer-aided design/computer-assisted manufacture technology was used to transfer the virtual plan to the surgical environment. The 3D position of the planned and placed implants, in terms of the linear deviations of the implant head and apex and the angular deviations of the implant axis, was compared by overlapping the pre- and postoperative computed tomography scans using dedicated software. Results: The comparison of 14 implants showed a mean linear deviation of the implant head of 0.56 mm (standard deviation [SD], 0.23), a mean linear deviation of the implant apex of 0.64 mm (SD, 0.29), and a mean angular deviation of the long axis of $2.42^{\circ}$ (SD, 1.02). Conclusions: In the present study, computer-aided flapless implant surgery seemed to provide several advantages to the clinicians as compared to the standard procedure; however, linear and angular deviations are to be expected. Therefore, accurate presurgical planning taking into account anatomical limitations and prosthetic demands is mandatory to ensure a predictable treatment, without incurring possible intra- and postoperative complications.

Accuracy of computer-aided template-guided oral implant placement: a prospective clinical study

Mario Beretta,Pier Paolo Poli,Carlo Maiorana 대한치주과학회 2014 Journal of Periodontal & Implant Science Vol.44 No.4

Purpose: The aim of the present study was to evaluate the in vivo accuracy of flapless, computer-aided implant placement by comparing the three-dimensional (3D) position of planned and placed implants through an analysis of linear and angular deviations. Methods: Implant position was virtually planned using 3D planning software based on the functional and aesthetic requirements of the final restorations. Computer-aided design/computer-assisted manufacture technology was used to transfer the virtual plan to the surgical environment. The 3D position of the planned and placed implants, in terms of the linear deviations of the implant head and apex and the angular deviations of the implant axis, was compared by overlapping the pre- and postoperative computed tomography scans using dedicated software. Results: The comparison of 14 implants showed a mean linear deviation of the implant head of 0.56 mm (standard deviation [SD], 0.23), a mean linear deviation of the implant apex of 0.64 mm (SD, 0.29), and a mean angular deviation of the long axis of 2.42° (SD, 1.02). Conclusions: In the present study, computer-aided flapless implant surgery seemed to provide several advantages to the clinicians as compared to the standard procedure; however, linear and angular deviations are to be expected. Therefore, accurate presurgical planning taking into account anatomical limitations and prosthetic demands is mandatory to ensure a predictable treatment, without incurring possible intra- and postoperative complications.

Computer-Assisted Modified Mid-Sacrectomy for En Bloc Resection of Chordoma and Preservation of Bladder Function

Han, In-Ho,Seo, Young-Jun,Cho, Won-Ho,Choi, Byung-Kwan The Korean Neurosurgical Society 2011 Journal of Korean neurosurgical society Vol.50 No.6

A 67-year-old woman presented for evaluation of severe coccygeal pain. The computed tomography scans and magnetic resonance imaging showed an asymmetric midline sacral tumor invading the right lower portion of S2. To preserve both S2 nerve roots and to obtain negative surgical margins, a modified mid-sacrectomy with an aid of a computed navigation system was performed. The sacral tumor was excised en bloc with negative tumor margins. Both S2 nerve roots were preserved and additional reconstruction was not necessary because of minimal resection of the sacroiliac joint. We report a case of a sacral chordoma which was excised en bloc with adequate surgical margins by a computer-assisted modified mid-sacrectomy. The computed navigation system may be a useful tool for tumor targeting and safe osteotomies in sacral tumor surgery via the posterior only approach.

Estimation of the effective dose of dental cone-beam computed tomography using personal computer-based Monte Carlo software

Kim, Eun-Kyung,Han, Won-Jeong,Choi, Jin-Woo,Battulga, Bulgan Korean Academy of Oral and Maxillofacial Radiology 2018 Imaging Science in Dentistry Vol.48 No.1

Purpose: To calculate the effective doses of cone-beam computed tomography (CBCT) using personal computer-based Monte Carlo (PCXMC) software (Radiation and Nuclear Safety Authority, Helsinki, Finland) and to compare the calculated effective doses with those measured using thermoluminescent dosimeters (TLDs) and an anthropomorphic phantom. Materials and Methods: An Alphard VEGA CBCT scanner (Asahi Roentgen Ind. Co., Kyoto, Japan) with multiple fields of view (FOVs) was used for this study. The effective doses of the scout and main projections of CBCT using 1 large and 2 medium FOVs with a height >10 cm were calculated using PCXMC and PCXMCRotation software and then were compared with the doses obtained using TLD-100 LiF and an anthropomorphic adult human male phantom. Furthermore, it was described how to determine the reference points on the Y- and Z-axes in PCXMC, the important dose-determining factors in this software. Results: The effective doses at CBCT for 1 large ($20.0cm{\times}17.9cm$) and 2 medium FOVs ($15.4cm{\times}15.4cm$ and $10.2cm{\times}10.2cm$) calculated by the PCXMC software were 181, 300, and $158{\mu}Sv$, respectively. These values were comparable (16%-18% smaller) to those obtained through TLD measurements in each mode. Conclusion: The use of PCXMC software could be an alternative to the TLD measurement method for effective dose estimation in CBCT with large and medium FOVs.