관상동맥 협착 진단을 위한 workstation별 QCA값의 비교 평가

김완역(Wan Yuk Kim),박건진(Kun Jin Park),변정인(Jung In Byun) 대한전산화단층기술학회 2007 대한CT영상기술학회지 Vol.9 No.1

Purpose As 64 Multi-Detector Computed Tomography systems were recently introduced and software has been variously developed, coronary CT angiography has been clinically come into notice. The patients, diagnosed with coronary arteriostenosis due to thrombi, were subject to this study. In this study, Quantitative Coronary Analysis value was comparatively analyzed by using the workstations produced by 4 companies respectively. Materials and Methods The 20 patients who showed the stenos is of the left anterior descending artery due to thrombi, among the patients, who underwent coronary CT angiography from November 2006 until January 2007, were subject to this study. The CT angiography was performed by using Toshiba Aquilion 64 under the condition of 120kVp, 400mA, 0.4sec tube rotation time. In result, the images of 75, 35, 45 and 90% with the sectional thickness of 0.5mm/0.4mm were taken and were transmitted to the workstation for image reconstruction. Extended brilliance workstation, Advantage workstation, Vitrea workstation, and TeraRecon workstation were used to measuring instruments, and QCA value, i.e., the stenos is degree of left anterior descending artery, was measured. Results 1. With regard to the QCA value based on area value, TeraRecon workstation showed the highest value but the value of PDW was lowest. 2. With regard to the QCA value based on average diameter value, the value of Vitrea workstation was highest but ADW also showed the lowest value. Conclusion QCA values were measured by using the workstations produced by 4 companies respectively; with the consequence that the values become different as to company and TeraRecon workstation and Vitrea workstation did not show conspicuous differences in case the vascular diameter is over 3mm. However, EBW and ADW showed remarkable differences in case the vascular diameter is less than 3mm. In case the vascular area is over 6mm², TeraRecon workstation and Vitrea workstation did not significant differences. When compared to QCA, the ability of workstation to quantitatively assess coronaiy artery diameters and coronary artery stenases is insufficient for clinical purposes

Adenosine triphosphate(ATP)를 이용한 운동부하 cardiac CT angiography 검사의 특성과 유용성

박건진(Kun Jin Park),김완역(Wan Yuk Kim),김문찬(Moon Chan Kim),한동균(Dong Kyoon Han) 대한전산화단층기술학회 2007 대한CT영상기술학회지 Vol.9 No.1

Purpose In the sphere of noninvasive CT (Computed Tomography), the perfusion evaluation of the left ventricle has been recently performed through the technical advance of MDCT (Multi-Detector Computed Tormgraphy) and the application of ECG gating. In this study, cardiac stress CT was performed by using ATP (Adenosine Triphosphate : DENOSIN??) on purpose to evaluate cardiac diseases through cardiac rest CT and myocardial image analysis, and to analyze the characteristics of cardiac stress CT and its usability. Materials and Methods The 33 patients, who underwent ATP cardiac CT from July 1, 2006 until January 31, 2007 in this hospital, were subject to this study and the medical data of 33 cases, collected from them, were applied to the research. ATP of 0.84mg/kg was slowly administered by using the syringe pump for 6 minutes. A stress view was taken after 5 minutes, and a rest view was taken 15 minutes after ATP was ceased. As regards image analysis, ROI (Region of Interest) was measured at the 4 segments in the ventricle, and PD (Physical Density) analysis and qualitative analysis were performed. Results 1. The average density of myocardial lesion was different, about between 50 and 60mg/cm³, as compared with those of other lesions. 2. The result of rest investigation was compared with the cases where myocardial ischemic lesion is observed in stress among the patients who showed the perfusion defects of myocardium. In result, the sensitivity to cardiovascular diseases was higher in stress investigation as compared with that of rest investigation. 3. Myocardial segments were mieasured by ROI analysis, with the consequence that the mild stenosis of the coronary artery could be diagnosed. Conclusion It is considered that the ATP-based cardiac stress CT is useful to compare evaluate the myocardium in cardiac excitement with stabilization, and to detect the coronary artery stenosis latent in patients. In addition, it is expected to research the characteristics of investigations through ROI analysis and image analysis, and to extend the existing diagnostic range in cardiac examination.

Coronary CT Angiography에서 Cardio ImageXact

김부환(Boo Hwan Kim),남윤철(Yoon Chul Nam),박건진(Kun Jin Park),김완역(Wan Yuk Kim),김문찬(Moon Chan Kim) 대한CT영상기술학회 2008 대한CT영상기술학회지 Vol.10 No.1

Purpose This research is that evaluate quality of reconstruction by Heart rate change in coronary arteries building CT examination about coronary artery disease patient who is being on the increase gradually and improve quality of reconstruction by searching for Cardiac reconstruction phase of most suitable in Heart rate that do using Cardio ImageXact that is TOSHIBA company’ s software. Materials and Methods From May, 2006 to July, 2007, Coronary CT Angiography did to 43 outpatients who examine and patient who undergo Coronary Artery Bypass Graft(CABG) surgical operation excepted. Patient does NPO during before examination and vital(BP, Heart rate) check and do 1/2T and carry on the head Metoprolol in case Heart rate more than 65, and in case is more than 75, effect conducted examination after 1 hour that is time that become maximum efficiency after did to take 1T(100mg). Reconstructed data using Cardio ImageXact that is TOSHIBA raw data reconstruction software by Auto(Best)phase, % method, ms(milli-second) method cardiac reconstruction raw data. Analysis method use Cardio ImageXact software acquires data as much as 0~99% to 1% space and 10ms space and R-R interval space to 10ms space in section of 2 level(aortic valve, mitral valve level)in raw data after examination and quality selects the best cardiac phase and acquire volume data in 3 method. Corona1y artery’ s quality in 3 cardiac recon mode analyzed comparison. Results Compared point through vessel analysis of target patient total 43 people on above 3 mode to use TOSHIBA company’ s cardiac phase recon software. 1. When Heart rate is 50~59 Average point becomes difference in segment No.2 and No.3, No.6, No.7 in 3 recon mode and difference did not become in other segment. 2. When Heart rate is 60~69 Could know that could acquire good image seeing that ms method acquires near point in 1 point in segment excepting segment No.10. 3. When Heart rate is 70~79 It is seldom difference of m.5 mode with % mode in each segment different 3 recon mode, showed near differentia in 1 point more with Auto(Best)phase mode, and % mode and ms mode could know that difference of average point is not great quality difference of image after recon in 0.1 point interior and exterior. 4. When Heart rate is over 80 Each segment different 3 recon mode could know in segment excepting segment No.9 that ms mode could get better image showing near point 1 point than Auto(Best) mode with % mode. Each segment different acquired point could make image that ms mode is better receiving near point in head of a family 1 point in Auto(Best) mode and % mode, ms mode to be 3 recon mode in each heart rate different each segment and % mode was some difference than ms mode, but did not show large difference. However, Auto(Best)recon mode to acquire good image missing near point in 1 point than above 2 mode difficulty know can. Also, Heart rate 3 recon mode did not show difference greatly in 50~59 but Heart rate is higher more than 60~69, 70~79, 80 difference of point that acquire could appear greatly and know qualitative difference of image. Conclusion By Auto(Best) and % mode or ms mode strongly in Heart rate that do stable very cardiac phase image that may not do reconstruction get. But, 75% and 45% cardiac phase are thought that this research is value more to supplement this to could not have gotten good image, and could not have good image in Auto(Best)phase usually in heart rate’ s case that do unstable. Reduce patient’ s re-procedure having gotten good image through this research, and expect to give large help diagnostic and treatment of heart vessel disease by supplying correct diagnostic information.

Bolus shield를 이용한 두경부 CT검사의 선량감소와 화질평가

김영균(Yung Kyoon Kim),김완역(Wan Yuk Kim),김광수(Kwang Soo Kim),변지혜(Ji Hye Byun) 대한전산화단층기술학회 2016 대한CT영상기술학회지 Vol.18 No.2

목적 : 두경부 CT검사에서 bismuth를 대체하여 인체 조직등가물질인 bolus 차폐물로 안구, 갑상선 부위를 차폐하여 임상적으로 사용가능한 지 화질과 선량감소 효과를 비교 평가하여 그 유용성을 확인하고자 한다, 대상 및 방법 : CT장비는 GE사의 VCT XTe(General Electric medical systems, Milwaukee, USA) CT를 이용하였고, 팬텀은 Rando phantom(model RAN-110, Churchin associate LTD, USA)과 ACR Phantom(Model #438, Gammex TMI, USA)을 사용하였다. 안구와 갑상선의 차폐를 위하여 bismuth로 코팅된 라텍스(F&L Medical Products Co. 0.060mmPb equivalent, USA)와 bolus (Eckert & Ziegler BEBIG Inc, Oxford, USA)를 이용하였다. 검사조건은 standard protocol에서 AEC 적용 시 120kVp, 300mAs, Noise Index는 9.05로 2.5mm thickness에 algorithm은 STD로 설정하였다. Low dose protocol은 100kVp를 적용하였고, fixed mA시 200 mA로 고정하였으며 나머지 조건은 동일하게 설정하였다. ACR phantom 인증 프로그램을 이용하여 균일도를 평가하였고, ADW 4.6(General Electric Healthcare, Barrington, USA) workstation을 사용하여 안구와 목 부위의 CT number와 noise 그리고 SNR을 구한 후, 비교 평가하였다. 조직선량의 측정을 위하여 형광유리선량계(GD-352M, 12mm, FGD-1000 reader, Asahi Techno Glass Co, shizuoka, Japan)을 사용하였다. 통계는 PASW Statistics 18. Release 18.0.0과 Microsoft Office Excel 2007을 이용하였다. 결과 : 균일도 평가 결과, bismuth 그룹은 low dose와 standard protocol은 각각 12.58과 12.17로 높게 나타났다. 그러나 bolus 1, 2, 3cm 그룹은 각각 1.16 ~ 2.42, 1.81 ~ 2.37로 적었다(p〈0.05). Non-shield한 그룹과 bismuth, bolus 1, 2, 3cm 차폐물을 부착한 그룹의 CT number와 noise 그리고 SNR을 측정하여 각각 T-test로 비교 평가한 결과, standard와 low dose protocol에서 AEC에 상관없이 bismuth는 모든 부위에서 유의한 차이가 발생하였다(p〈0.05). 하지만 bolus는 대부분 비슷하거나 유의한 차이를 보이지 않았다(p〈0.05). Bolus 두께에 따른 장기의 CT number는 AEC의 적용여부와 측정 장기에 따라 일부 유의한 차이가 발생하였으나, 5.73 HU 이내로 미미하였다. Noise는 두께가 증가될수록 높아졌지만 그 차이는 안구에서 1.07 ~ 3.69이었고, 목의 상부와 중간 그리고 하부는 각각 0.14 ~ 2.09, 0.06 ~ 2.86, 0.14 ~ 2.19 이내로 매우 미미하였다(p〈0.05). 차폐물에 변화에 따른 안구와 갑상선의 선량감소율은 Bismuth 그룹의 안구는 26.1 ~ 34.7% 감소되었으며 갑상선은 34.5 ~ 43.5% 감소되었다. 그리고 Bolus 1, 2, 3cm를 부착한 그룹의 안구선량은 9.2 ~ 26.53% 그리고 갑상선은 6.6 ~ 28.9% 감소되었다. 결론 : 두경부 CT 검사에서 조직등가물질인 bolus 차폐물은 갑상선과 안구의 조직선량을 감소시키면서 화질에 영향을 거의 미치지 않는 유용한 차폐체임을 알 수 있었다. 또한 bolus 차폐물은 AEC의 적용여부에 상관없이 성인기준의 120kVp뿐만 아니라 100kVp의 저선량 구간에서도 매우 유용하였다. Purpose : This study aims to demonstrate the effectiveness with the comparison and evaluation of image quality and dose reduction effect for clinical usage protecting eye and thyroid with bolus in neck CT. Materials and Methods : CT equipment which used in this study were GE VCT XTe 64 slice MDCT(General Electric medical systems, Milwaukee, USA) with Rando Phantom(model RAN-110, Churchin associate LTD, USA) and ACR Phantom(Model #438, Gammex TMI, USA). For the protection of eye and thyroid, we used the latex (F&L Medical Products Co. 0.060 mmPb equivalent, USA) and Bolus (Eckert & Ziegler BEBIG Inc, Oxford, USA) covered bismuth. The parameters of standard protocol were 120 kVp, Noise Index 9.05, 100 ~ 300 mA, 2.5 mm thickness, pitch 0.984, and STD algorithm were set with AEC. Low dose protocol is adapted 100kVp and Fixed mA used as 200mA. The uniformity was evaluated by using ACR phantom program, and we evaluated CT number and noise of eye and neck area for using ADW 4.6(General Electric Healthcare, Barrington, USA) workstat ion. For the measurement of organ dose, it used fluoroglass dosimeter (GD-352M, 12 mm, FGD-1000 reader, Asahi Techno Glass Co, shizuoka, Japan). Program used in this study were PASW Statistics 18. Release 18.0.0 and Microsoft Office Excel 2007. Results : As the result of assessment, low dose and standard protocol in bismuth group shows 12.58 and 12.17 highly. But, it was low as 1.16 ~ 2.42, 1.81 ~ 2.37 with 1, 2, 3 cm bolus(p〈0.05). As the result of comparison evaluation on the SNR, noise, CT number in 5 groups (Non-shield, with Bismuth, with 1, 2, 3 cm Bolus) by T-test, showed significant differences on non-shield and Bismuth groups in standard and low-dose protocol regardless of AEC(p〈0.05). But, the Bolus group didn t show the significant difference(p)0.05). CT number of organs depending on the thickness of the Bolus showed insignificant differences (5.73 HU) in applying AEC or not and each organs. Noise was increased with thickness, the differences were very slight 1.07 ~ 3.69 in eyeball(p〈0.05), 0.14 ~ 2.09 in upper part of the neck, 0.06 ~ 2.86 in medial part of the neck, 0.14 ~ 2.19 in lower part of the neck. As the result of dose reduction, it shows the reduction of 26.1 ~ 34.7% of eye and 34.5 ~ 43.5% of thyroid in bismuth group. And it shows 9.2 ~ 26.53% eye dose and 6.6 - 28.9% thyroid in Bolus 1, 2, 3 cm attached. Conclusion : In neck CT, the bolus shield is effective shield material because it rarely damage to the image quality with reducing thyroid and eye organ dose. Also bolus shield is very useful at 100 kVp area despite of 120 kVp in Adult without the adaptation of AEC.

Single source dual-energy CT에서 복부 장기별 energy level의 최적화

김영균(Yung Kyoon Kim),김완역(Wan Yuk Kim),김광수(Kwang Soo Kim) 대한CT영상기술학회 2014 대한CT영상기술학회지 Vol.16 No.2

목적 : Single Source Dual Energy CT를 이용한 복부검사 시 Optimal CNR을 이용하여 장기별 최적의 keV를 찾고자 하였다 대상 및 방법 : 임상연구는 2013년 8월 1일부터 12월 30일까지 GE Discovery 750 HD(General Electric medical systems, Milwaukee, USA) CT를 이용하여 복부검사를 시행한 124명의 환자를 대상으로 데이터를 수집하였다. ADW 4.6(General Electric Healthcare)에서 제공하는 Optimal CNR Tool을 이용하여 장기별keV를 측정하였다. 간, 비장, 췌장, 담도, 신장, 방광, 지방, 근육, 뼈(L-spine, Pelvis)에 target ROI를 그리고 위안의 물에 background를 설정하여 keV를 구하였다. 또한 환자의 연령과 BMI 및 조영제 주입속도가 최적의 CNR에 영향을 미치는지 분석하였다. Scan 조건은 120kVp, 270mAs, slice thickness와 interval은 2.5mm/2.5mm, FOV는 35, pitch는 0.984, rotation time은 0.7sec, algorism은 soft로 설정하였다. 조영제 주입 후, scan time은 70sec로 설정하였다. 통계는 PASW Statistics 18. Release 18.0.0과Microsoft Office Excel 2007을 이용하였다. 결과 : 모든 복부장기는 60에서 75keV 범위에서 최적의 CNR이 측정되었고, 그 중 99.2%이상 65~70keV의 범위에서 측정되었다. 또한 평균과 중위수를 비교해 본 결과 66~68keV 범위에 있었고, 최빈값은 65에서 69keV의 범위에 있었다. 장기별 CNR의 평균과 표준편차는 간 8.45±9.93, 비장 8.77±2.96, 신장 13.08±18.06, 담도 1.79±3.03, 췌장 7.59±8.88, 방광 2.38± 2.99, 내장지방 -5.43±7.48, 외장지방 -6.02±8.84, 근육 4.16±5.80, 대동맥 13.17±16.17, 요추 15.38± 22.43, 골반 18.27± 16.84로 측정되었다. 환자의 연령과 BMI 및 조영제 주입속도에 따른 keV의 변화여부를 평가하기 위하여 일원배치 분산분석을 시행한 결과, 집단간 P-value가 모두 0.05보다 크므로 유의성이 없었다. 결론 : SSDE CT로 복부검사 시, 장기별로 65~70keV의 범위에서 적절하게 keV를 설정하여 사용하면 최적의 CNR에 해당되는 영상을 획득할 수 있다. 또한 복부 routine 검사의 경우 최적의 CNR은 66~68keV이다. 연령과 BMI 그리고 조영제 주입속도에 따른 영향은 없었다. Purpose : To find optimal keV using Optimal CNR when using Single source dual energy CT Subject and Method : Clinical studies were collected the data targeting 132 patients doing abdomen exam by using GE Discovery 750 HD(General Electric medical systems, Milwaukee, USA) CT in 2013 August 1 to December 30. To measure each organ keV using Optimal CNR Tool supported from ADW 4.6(General Electric Healthcare). To have keV after drawing ROI on liver, spleen, pancreas, bile duct, kidney, bladder, fat, muscle and bone (L-spine, Pelvis), and then setting background on water in stomach. Also, to analyze that varying factor following patient’s age, BMI and contrast injection rate speed affect optimal CNR. Scan condition was 120kVp/ 270mAs, Slice thickness and Interval 2.5mm/2.5mm, FOV was 35, pitch was 0.984/1 and Rotation Time 0.7sec, Algorism set soft, and clinic set 70sec scan time after 120cc contrast injection. Statistic was used PASW Statistics 18. Release 18.0.0 and Microsoft Office Excel 2007. Results : All abdomen organs shows the optimal CNR between 60 and 75keV, over 99.2% was included the range of 65~70keV among the rest. Also, as the comparison the average and the median, the result shows under 66~68keV range. And the mode was between 65 and 69keV. CNR average and standard deviation of each organ were measured liver 8.45±9.93,spleen 8.77±2.96, kidney 13.08±18.06,bile duct 4.16±5.80, pancreas 7.59±8.88,bladder 2.38±2.99,, intra-abdominal fat -5.43±7.48, supra abdominal fat -6.02±8.84, muscle 4.16±5.80, aorta 13.17±16.17,lumbar spine 15.38± 22.43, and pelvis 18.27± 16.84. As doing One-Way ANOBA for evaluating the keV variation following patient’s age, BMI and contrast injection speed, the result shows no significance because intergroup P-value was all higher than 0.05. Conclusion : When doing abdomen exam using SSDE CT, if using properly to get images applied optimal CNR within the 65~70keV range of each organ, it could be to get the images of optimal CNR. Also, for abdomen routine exam, the optimal CNR is 66~68keV. And, no effects following age, BMI and contrast injection speed

ODM과 bismuth를 이용한 수정체와 갑상선 선량 감소 효과 및 영상 화질 평가

이승현(Seung Hyun Lee),오현식(Hyun Sik Oh),김완역(Wan Yuk Kim),장광현(Kwang Hyun Chang) 대한CT영상기술학회 2016 대한CT영상기술학회지 Vol.18 No.2

Purpose : It is to know the method of the limiest dose reduction of lens and Thyroid which is comparative high sensitivity with the implementation of the best images during head and neck exam by using ODM(Organ Dose Modulation, ODM) that is AOBCM(automated organ current modulation) by GE manufacture company, AEC(Automatic exposure control) and bismuth. Materials and Methods : CT equipment is used Discovery CT 750HD(General Electric Medical System, Milwaukee, Wisconsin USA), and Alderson Rando phantom(CNMC Company, USA) is used with attached Radiophoto Luminescent Glass Dosimeter five to head and six to neck for dose measurement using tour methods(AEC, ODM, bismuth, ODM+bismuth) with 10 times scan and acquired average value. Also to evaluate image quality, we used noise and CT number, and to measure linearity and uniformity by using ACR phantom (Model #438, Gamex RMI, USA). Statistic is used MedCalc version 16.1 to have average and standard deviation of all measurement values, and it could be judged statistically when p-value under 0.05 by AVOVA test. Result : The standard by the usage of AEC, the measured dose result shows that lens were ODM 19.2%, bismuth 32.9%, ODM and bismuth 46.7% down, and to Thyroid shows that ODM 31.2%, bismuth 24.9%, ODM and bismuth 56.8% down. To evaluate image quality for noise, lens shows that ODM 7.1 %, bismuth 17.7%, ODM and bismuth 13.3% increase, to Thyroid shows that ODM 10.1 %, bismuth 30.0%, ODM and bismuth 36.9% increase, for CT number values, lens show that ODM 0.3%, bismuth 50.0% and ODM+bismuth 48.8% increase, to Thyroid shows that ODM 1.9% down, bismuth 296.2%, ODM and bismuth 305.8% increase. To evaluate using ACR phantom, for the usage of bismuth, linearity and uniformity were out of tolerance field recommended ACR because of artifact, by ODM case was under tolerance field for ACR recommendation. To judge statistical significance test, as the result of dose, noise and CT number values by ANOVA test, we confirmed that all results were significant with p-value< 0.05. Conclusion : When using ODM, it was known that dose could be reduced over 25% and increased noise, but continued CT number. Also, neck which is lower thickness compared head shows low noise changes and CT number values continuation. Through this result, it is considered that ODM is more effective method for dose reduction and image quality to less thickness area. 목적 : GE사에서 개발한 자동장기기준선량제어장치(automated organ current modulation, AOBCM) 인 ODM(Organ Dose Modulation, ODM)과 자동노출제어장치(Automatic exposure control, AEC), 그리고 비스무스(bismuth)를 이용하여 두경부 검사 시 최고의 영상을 구현하면서 상대적으로 감수성이 높은 장기인 수정체와 갑상선의 선량을 최소로 낮추는 방법을 찾아보고자 한다. 대상 및 방법 : CT장비는 Discovery CT 750HD(General Electric Medical System, Milwaukee, Wisconsin USA)를 사용하였고, 선량측정을 위해 Alderson Rando phantom(CNMC Company, USA)을 이용하여 두부에 5개, 경부에 6개씩 형광유리선량소자를 이용하여 AEC, ODM, bismuth, ODM+bismuth 4가지 방법으로 10회 scan하여 평균값을 구하였다. 또한 화질평가를 위해 noise와 CT number값을 이용하여 평가하였으며, 영상평가를 위해 ACR phantom(Model #438, Gamex RMI, USA)을 사용하여 직선성과 균일성을 측정하였다. 통계는 MedCalc version 16.1을 사용하여 모든 측정치의 평균과 표준편차를 구하였으며, AVOVA로 통계분석 하여 유의확률(p-value)가 0.05 미만일 때 통계적으로 유의하다고 판단하였다. 결과 : AEC를 사용한 경우를 기준으로 선량을 측정한 결과 수정체는 ODM 19.2% bismuth 32.9% ODM과 bismuth 46.7% 감소하였고, 갑상선은 ODM 31.2%, bismuth 24.9%, ODM과 bismuth 56.8% 감소하였다. 화질평가를 위해 측정한 noise값의 경우 수정체는 ODM 7.1%, bismuth 17.7%, ODM+bismuth 13.3% 증가하였고, 갑상선은 ODM 10.1%, bismuth 30.0%, ODM+bismuth 36.9% 증가하였으며, CT number값의 경우 수정체는 ODM 0.3%, bismuth 50.0%, ODM+bismuth 48.8% 증가하였으며, 갑상선은 ODM 1.9% 감소하였고 bismuth 296.2% ODM+bismuth 305.8% 증가하였다. ACR phamtom을 이용한 영상평가에서는 bismuth를 사용하였을 경우 Artifact로 인해 직선성과 균일성 모두 ACR에서 권고하는 허용범위에 속하지 않았으며, ODM을 사용한 경우에는 ACR에서 권고하는 허용범위에 속하였다. 통계적 유의성을 판단하기 위하여 ANOVA test로 각각의 선량, noise, CT number값을 검정한 결과 모든 측정값이 p-value<0.05 미만으로 유의하다고 판단하였다. 결론 : ODM을 사용하였을 경우 선량은 25% 이상을 감소시키면서 noise 값은 증가하지만 CT number값은 유지됨을 알 수 있다. 또한 두부보다 상대적으로 두께가 얇은 경부의 경우 noise값은 변화가 적으면서 CT number값은 유지됨을 알 수 있다. 이를 통해 ODM은 두께가 얇은 부위에 선량감소 및 영상평가에 더욱 효과적이라 사료된다.