• 한국콘텐츠학회논문지
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• 제19권8호
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• pp.284-292
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• 2019

소아 흉부 CT 검사 시 방사선 피폭을 최소화 하면서 진단적으로 가치가 높은 영상을 얻기 위해서 Helical mode, High-pitch mode, Volume Axial mode를 적용하여서 선량, 검사시간, 화질을 비교하여 유용성을 평가하고자 한다. Revolution(GE Healthcare, Wisconsin USA)을 이용하여 PBU-70팬텀을 Helical mode, High-pitch mode, Volume Axial mode로 각각의 그룹으로 나누어서 관전압 80kVp, 조건으로 30회 검사를 실시하였다. 영상을 획득 한 후에 각각의 영상에 심장(Heart), 뼈(Bone), 폐(Lung), Back-ground air에 ROI를 설정하고 CT number(HU)와 noise(SD)값을 측정하여 평균값을 구하고 SNR과 CNR을 측정하였고, 장비에서 직접 제공하는 DLP값 비교하였다. 통계적인 유의성을 확인해보기 통계 분석은 SPSS 21.0을 사용하여 ONE-WAY-ANAOVA를 시행하였다. 본 실험을 통해 검사 시 volume axial mode 사용 시 가장 적은 선량으로 영상의 화질 저하 없이 빠른 시간에 검사가 가능하였다. 16cm의 detector coverage 가 모든 소아 흉부 CT검사에 적용하기에 제한점이 있으나 가능한 소아환자에 있어 적극적인 활용을 추천하며 volume axial mode의 다른 검사부위 적용에 대한 지속적인 연구가 필요하리라 사료된다.

• Journal of Trauma and Injury
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• 제25권4호
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• pp.209-216
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• 2012

Purpose: The objectives of this study are to classify chronic subdural hematomas based on brain computerized tomographic scan (CT scan) findings and to determine the mechanism of evolution and treatment methods. Methods: One hundred thirty-nine patients who were diagnosed with a chronic subdural hematoma and who available for follow up assessment 6 months post-surgery were analyzed retrospectively. The presence of trauma and past medical history were reviewed and evaluation criteria based on brain CT scan findings were examined. Results: Initial brain CT scans revealed a chronic subdural hematoma in 106 patients, a subdural hygroma in 24 patients, and an acute subdural hematoma in 9 patients. In all cases where the initial acute subdural hematoma had progressed to a chronic subdural hematoma, final was a hypo-density chronic subdural hematoma. In case where the initial subdural hygroma had progressed to a chronic subdural hematoma, the most cases of hematoma were hyper-density and mixed-density chronic subdural hematoma. In total, 173 surgeries were performed, and they consisted of 97 one burr-hole drainages, 70 two burr-hole drainages and 6 craniotomies. Conclusion: This study demonstrates that rebleeding and osmotic effects are mechanisms for enlarging of a chronic subdural hematoma. In most cases, one burr-hole drainage is a sufficient for treatment. However, in cases of mixed or acute-on-chronic subdural hematomas, other appropriate treatment strategies are required.

• Journal of Ginseng Research
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• 제36권4호
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• pp.469-476
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• 2012

Raw ginseng root of Panax ginseng is graded according to its shape and the quality of its internal tissue. A variety of grades are sold with prices according to grade. If an inferior raw ginseng is purchased, the consumer experience an economic loss. This research was conducted in order to explore the possibility of developing a noninvasive method for investigating raw ginseng's internal tissue. It has been determined that computed tomography (CT) scanner images agreed with actual cross-sections of raw ginseng. CT images were obtained to assess the internal portions of raw ginseng, and CT scans of raw ginseng were thoroughly measured using the Hounsfield unit (HU) system, since it allows for a more detailed analysis compared to nuclear magnetic resonance imaging. HU is a measure of attenuation used for CT images, with each pixel being assigned a value using a scale on which air is defined as -1000, water as 0 and compact bone as +1000. It takes about one second to process are slice and produce an image of the raw ginseng by a one channel CT scanner. An image good enough to discriminate the internal tissues can be obtained in 1/24 seconds with a one-channel CT scanner. Using this method, images of raw ginseng can be obtained and the characteristics of the internal tissues can be observed in a short time.

• Journal of Magnetics
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• 제21권4호
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• pp.603-615
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• 2016

In this study, in order to determine the validity and accuracy of MR imaging of 3D gradient dual echo 2-point DIXON technique for measuring abdominal adipose tissue volume and distribution, the measurements obtained by CT were set as a reference for comparison and their correlations were evaluated. CT and MRI scans were performed on each subject (17 healthy male volunteers who were fully informed about this study) to measure abdominal adipose tissue volume. Two skilled investigators individually observed the images acquired by CT and MRI in an independent environment, and directly separated the total volume using region-based thresholding segmentation method, and based on this, the total adipose tissue volume, subcutaneous adipose tissue volume and visceral adipose tissue volume were respectively measured. The correlation of the adipose tissue volume measurements with respect to the observer was examined using the Spearman test and the inter-observer agreement was evaluated using the intra-class correlation test. The correlation of the adipose tissue volume measurements by CT and MRI imaging methods was examined by simple regression analysis. In addition, using the Bland-Altman plot, the degree of agreement between the two imaging methods was evaluated. All of the statistical analysis results showed highly statistically significant correlation (p<0.05) respectively from the results of each adipose tissue volume measurements. In conclusion, MR abdominal adipose volumetry using the technique of 3D gradient dual echo 2-point DIXON showed a very high level of concordance even when compared with the adipose tissue measuring method using CT as reference.

• Imaging Science in Dentistry
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• 제50권4호
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• pp.299-307
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• 2020

Purpose: The diagnosis of chronic rhinosinusitis requires a comprehensive knowledge of the signs and symptoms of the disease and an accurate radiographic assessment. Computed tomography (CT) is the superior imaging modality for diagnosis of chronic rhinosinusitis. However, considering the lower dose and higher resolution of cone-beam computed tomography (CBCT) compared to CT, this study aimed to assess the agreement between the findings of CBCT and functional endoscopic sinus surgery (FESS). Materials and Methods: This descriptive prospective study evaluated 49 patients with treatment-resistant chronic rhinosinusitis who were candidates for FESS. Preoperative CBCT scans were obtained before patients underwent FESS. The agreement between the CBCT findings and those of FESS was determined using the kappa correlation coefficient. The frequency of anatomical variations of the paranasal sinuses was also evaluated on CBCT scans. Results: Significant agreement existed between pathological findings on CBCT scans and those of FESS, such that the kappa correlation coefficient was 1 for mucosal thickening, 0.644 for nasal deviation, 0.750 for concha bullosa, 0.918 for nasal polyp, 0.935 for ostiomeatal complex (OMC) obstruction, and 0.552 for infundibulum thickening. Furthermore, 95.9% of patients had 1 or more and 79.6% had 2 or more anatomical variations, of which nasal deviation was the most common (67.3%). Conclusion: Considering the significant agreement between the findings of CBCT and FESS for the detection of pathological changes in the paranasal sinuses, CBCT can be used prior to FESS to detect chronic rhinosinusitis and to assess anatomical variations of the OMC.

• Journal of Trauma and Injury
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• 제24권1호
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• pp.25-30
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• 2011

Purpose: Major trauma patients should be transferred to a definitive care facility as early as possible because prompt management will prevent death. This study was designed to discover the obstacles leading to delayed transfers under the current emergency medical system in Korea and whether there are any negative outcomes associated with conducting procedures at primary care hospitals prior to transferring patients to higher levels of care. Methods: The medical records of major trauma patients with an Injury Severity Score above 15 within the past year were reviewed. Patients were divided three groups as follows: (A) came directly to our emergency center, (B) were transferred without CT or MRI scan at the primary care hospital and (C) transferred with CT or MRI scans. The transfer time of each group were compared and analyzed statistically. Additionally, the number and type of imaging performed at the primary care hospital were analyzed. Results: All qualified patients (n=276) were enrolled in this study: 121 patients in group A; 104 in group B; 51 in group C. There was a statistically significant difference in the transfer time between the three groups (p-value<0.001), and 79 (28.6%) were transferred to an emergency medical center within one hour. In group C, CT or MRI scans were performed an average of 1.86 times at the primary care hospital, and the median transfer time was 4 hours 5 minutes. Conclusion: Only 28.6% of the cases in the study arrived within the golden hour at a definitive care facility. Such delays are in part the result of prolonged times at the primary care hospital for radiologic examinations, such as CT or MRI scans. Major multiple trauma patients should be transferred to a definitive care facility directly or as soon as the primary survey and the resuscitation of Advanced Trauma Life Support guideline are completed at the primary care hospital.

• 대한영상의학회지
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• 제82권6호
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• pp.1493-1504
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• 2021

목적 관상동맥 칼슘스코어(coronary artery calcium score; 이하 CACS)를 측정하는 데 있어 비 조영증강 흉부 CT에서 16 cm 축상 촬영 기법의 유용성을 알아보고자 하였다. 대상과 방법 20명의 환자를 대상으로 16 cm 축상 촬영 기법을 이용한 비 조영증강 흉부 CT와 칼슘 스코어 CT를 전향적으로 시행하였다. 흉부 CT는 세 가지 절편 두께(0.625, 1.25, 2.5 mm)로 재구성하여, Agatston 방법을 통해 관상동맥 칼슘스코어를 측정하였다. 다양한 절편 두께의 비 조영증강 흉부 CT와 칼슘스코어 CT의 관상동맥 칼슘스코어를 비교하고, 단면 분석을 통해 CACS의 임상적 중요성에 대한 일치를 확인하였다. 또한 각각의 석회화 병변들을 위치와 크기로 나누어 비 조영증강 흉부 CT와 칼슘스코어 CT에서 일대일 비교를 시행하였다. 결과 2.5, 1.25, 0.625 mm 절편 두께의 흉부 CT와 칼슘스코어 CT의 CACS 상관 계수는 각각 0.9850, 0.9688, 0.9834였다. 흉부 CT와 칼슘스코어 CT 간의 CACS 차이는 0.625 mm에서 -21.4%, 1.25 mm에서 -39.4%, 2.5 mm 절편 두께에서 -76.2%였다. CACS 구간별 분석에서 절편 두께별로 16명(80%, 0.625 mm), 16명(80%, 1.25 mm), 13명(65%, 2.5 mm)의 환자가 관상 동맥 질환의 위험도 구간이 일치하였다. 관찰자 간 일치도는 모든 절편 간격에서 높게 나타났다. 세 절편 두께 중에서는 0.625 mm CT에서 석회화 병변에 대한 민감도가 가장 높았다. 결론 16 cm 축상 촬영 기법을 이용한 비 조영증강 흉부 CT에서 electrocardiogram 동기화 없이도, 0.625 mm 절편 간격에서 칼슘스코어 CT에서의 CACS와의 유사한 값을 얻을 수 있었다. 이를 통해 추가 방사선 노출 없이, 심혈관 질환 위험을 예측하는 데 도움이 될 수 있다.

• Journal of Korean Neurosurgical Society
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• 제29권7호
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• pp.886-890
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• 2000

Objective : placement of ventricular catheter is important to achieve long-term patency of the shunt system. We describe a method of calculating the insertion site, trajectory, and the length of the ventricular catheter using CT parameters in shunt surgery. Patients and Methods : These can be rapidly obtained using a caliper from a scout cut and two axial scans at lateral ventricular and upper 3rd ventricular level. To compare this technique with traditional one, we analyzed 40 consecutive patients who underwent shunt surgery. Results : Of 20 patients undergoing ventriculoperitoneal shunt insertion using this technique, none had poor location of the proximal catheter. In the counterpart, 9 patients had poor location(p＝0.001). The number of patients who required revision surgery were also lower in the group using this technique, but it was not statistically significant (4 versus 2, p＝0.422). Mean follow-up period was shorter in this technique group. Conclusion : This technique provides an accurate placement of the proximal catheter without special instrument or additional expenses.

• 핵의학기술
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• 제16권2호
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• pp.68-80
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• 2012

감쇠 보정법과 산란 보정법은 정량적인 PET검사를 하기 위한 필수적인 방법이다. PET/CT에서는 PET에서 사용하는 소멸방사선과 CT의 X선이 같은 전리 방사선이기 때문에 측정에 의한 CT의 Hounsfield Units를 감쇠 계수로 전환해서 감쇠보정, 산란보정이 가능하다. 그러나 PET/MR에서 MR는 강한 자기장을 걸어 수소밀도와 조직의 이완률차이로 되돌아오는 변화로 신호를 획득하기 때문에 CT처럼 전환하는 것은 불가능하다. Ingenuity TF PET/MR장비는 soft tissue, lung, air로 3구역을 segment하여 MR 감쇠지도를 얻는다. 이에 신호획득원리가 완전히 상이한 PET/MR과 PET/CT에 대한 정량적 평가를 하고자 한다. Phantom study로 uniform cylinder phantom에 증류수 9293 ml와 $^{18}F$-FDG 199.8 MBq를 넣고 magnetic stirrer를 이용하여 균일하게 교반한 후 60 min부터 15분 간격으로 Ingenuity TF PET/MR, Gemini TF 64, Biograph Truepoint 40를 이용하여 각각 single-bed로 2 min씩으로 영상을 얻었다. phantom의 중심부분 10개의 slice에 대한 동일한 관심영역을 그려 SUVs를 측정하고 평균, 표준편차를 구하였다. 그리고 임상적용을 위한 평가로 $^{18}F$-FDG 섭취가 정상인 환자를 대상으로 90 sec/bed씩 Ingenuity TF PET/MR을 시행한 후 Gemini TF 64 PET/CT 검사를 실시하였다. 각각의 data에서 lung, liver, spleen, bone 위치에 동일한 관심영역을 그려 SUVs 최대값과 평균값을 측정하고, %Difference를 구하였다. 또한, PET 장비들 사이에서의 일치도를 평가하기 위해 Bland-Altman plot 분석을 하였다. Phantom study에서 3가지 장비에서 측정한 SUVs 최대값과 평균값은 Biograph Truepoint 40, Gemini TF 64, Ingenuity TF PET/MR 순으로 높은 것을 확인할 수 있었다. patients study에서는 MR과 CT로 감쇠 보정한 PET장비의 SUVs 최대값과 평균값이 서로 유의미한 차이가 없었다.(p<0.05) Lung에서 left middle lobe과 transverse bone을 제외하고는 MR로 감쇠 보정한 PET의 SUVs가 대체로 낮았다. Bland Altman Plot으로 분석한 결과 대부분의 항목에서 95% 신뢰구간의 일치한계선내에서 측정되었다. PET/CT에서는 time of flight 기능을 가진 PET이 SUVs가 낮게 측정되었다. PET/MR과 PET/CT에서 알아본 SUVs차이는 MR을 이용한 분할 감쇠 보정방법이 CT를 사용한 측정 감쇠보정방법보다 SUVs가 낮게 측정되었다. 이러한 다른 감쇠 보정법에 의한 SUVs의 차이는 임상적으로는 용인할 수준에 있었지만, 향후 PET/MR와 PET/CT의 정량적인 값을 비교 분석할 때 PET 장비들간의 특성은 고려할 필요가 있다.

• 한국방사선학회논문지
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• 제13권2호
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• pp.169-174
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• 2019

$^{99m}Tc$을 이용하는 검사를 받고 CT 검사를 진행했을 때 CT 영상에 $^{99m}Tc$이 미치는 변화에 대하여 정량적으로 알아보고자 하였다. Resolution phantom과 Water phantom에 $^{99m}Tc$ 740 MBq를 주입 전 후 80 kVp와 120 kVp로 관전압을 변화시켜 CT Scan하였다. 연구결과 $^{99m}Tc$ 주입 전 후 신호강도는 각각 0.173, 0.241의 감소하였으며, 공간분해능은 각각 0.090, 0.109로 증가하였다. CT 촬영을 $^{99m}Tc$의 유효 반감기를 고려하여 $^{99m}Tc$의 감마선이 CT에 영향을 미치지 않도록 일정한 시간 후 진행함으로 영상의 변화를 줄일 수 있을 것으로 사료된다.