Principle of spiral CTA ; Image Quality

임흥선,Im, Heung-Seon 대한디지털의료영상학회 1997 대한디지털의료영상학회논문지 Vol.3 No.1

64-MDCT에서의 CT Aortography와 조영제 주입 방법

이우상(Woo sang Lee),임흥선(Heung seon Im) 대한CT영상기술학회 2013 대한CT영상기술학회지 Vol.15 No.1

MDCT의 기술적인 발전과 보급으로 이용률과 보급률이 증가되고 있으며, CT Aortography 또한 진단적 정확도의 향상, 검사시간의 단축과 편리성 등으로 임상응용의 폭이 증가하고 있다. 각종 언론과 방송매체의 영향으로 CT 검사 시 방사선량의 위험성과 조영제의 부작용에 관한 정보가 넘쳐나고 있고, 이에 대하여 검사실로 문의하는 경우도 많아지고 있는 실정이다. SDCT에서와는 달리 64 MDCT장비에서는 갠트리의 회전속도가 빨라지고, 검출기 열의 수가 많아지게 되어 검사부위의 스캔시간이 짧아졌다. 이에 따라서 SDCT에서와는 다른 64 MDCT에서의 CT Aortography의 검사법과 조영제 프로토콜에 대한 연구의 필요성이 요구되어 진다. 이에 본 연구에서는 64 MDCT에서의 CT Aortography 검사법과 조영제 주입 방법에 대하여 국내외의 문헌 및 고찰을 통해 정리하여 기초자료로 활용하고자 한다. The usage and penetration rates of MDCT are increasing according to the technical development and penetration and the clinical application of CT Aortography is also increasing according to the improvement of diagnostic accuracy, shortened examination time and convenience. Owing to various reports of the press and the broadcasting media, a lot of information about danger of radiation dose and side effects from the contrast media is yielded and the inquiries to the CT examination room are increasing. Unlike the SDCT, the 64-MDCT has shorter scan time because of the faster gantry rotation speed and increased amount of CT detector rows. Accordingly, the study of different scan method of CT Aortography and protocols for contrast media in 64-MDCT is necessary. In this study, we investigated the scan method of CT Aortography and protocols for contrast media through home and abroad literature and gave careful consideration and arranged it as a basis for the application.

뇌혈관 조영CT에 대한 320-MDCT에서의 영상의 질 및 방사선량

차영경(Yeong Kyeong Cha),이민수(Min Su Lee),이성주(Seong Joo Lee),임흥선(Heung Seon Im),손철호(Cheol Ho Son) 대한CT영상기술학회 2012 대한CT영상기술학회지 Vol.14 No.2

목적 본 연구는 뇌혈관 조영CT에 대한 320-MDCT와 64-MDCT에서의 영상의 질과 방사선량을 비교하고자 한다. 대상 및 방법 320-MDCT와 64-MDCT에서 뇌혈관 조영CT를 실시한 60명의 환자(남성 28명, 여성 32명; 연령분포, 20-84세; 평균나이 58±14.8세)를 대상으로 320-MDCT 그룹과 64-MDCT 그룹으로 나누었다. 횡단 다면 재구성 영상과 볼륨 렌더링 혈관조영CT 영상을 획득하여 영상의 질을 평하였다. 중대뇌동맥과 기저동맥에서 각각 CT number와 Noise, SNR을 측정하였고, DLP값과 유효선량(ED)을 비교하였다. 유효선량은 DLP값과 두부 촬영 변환계수(k=0.0021 mSv/mGy×cm)로 계산하였다. 정량적 영상분석을 위해 영상의학과 교수 한명이 4점 척도를 이용하여 영상의 질을 평가하였다. 정량적 분석과 정성적 분석을 위해 각각 Independent t-test를 사용하여 통계적 유의성을 검정하였다. 결과 중대뇌동맥과 기저동맥에서의 CT number값은 두 그룹간 통계적으로 유의한 차이를 보였다. (p=0.000) 중대뇌동맥 Noise는 64-MDCT 보다 320-MDCT에서 유의하게 낮게 나타났다(p=0.016). 중대뇌동맥과 기저동맥의 SNR은 320-MDCT에서 모두 유의하게 높게 나타났다(p=0.000). 각 그룹에서 측정한 유효선량은 64-MDCT보다 다 320-MDCT에서 유의한 차이를 보이며 14% 낮게 나타났다(p=0.000). 영상의 질은 두 그룹 모두 우수했고 64-MDCT보다 320-MDCT에서 유의하게 높게 나타났다(p=0.000). 결론 320-MDCT에서의 뇌혈관 조영CT는 64-MDCT보다 낮은 선량으로 높은 영상의 질을 제공함으로써 뇌혈관 질환의 진단에 있어 유용한 검사라고 생각된다. I. Purpose The purpose of this study was to compare image quality and radiation dose of 320- and 64-MDCT for whole brain CT angiography. II. Meterial and Methods A total of 60 patients (28 men, 32 women; age range, 20~84 years; mean age, 58±14.8 years) who underwent contrast-material-enhanced brain CT angiography with 320- and 64-MDCT were randomized into two groups: the 320-MDCT group and the 64-MDCT group. Transaxial multiplanar reformatted images and volume-rendered CT angiogram; were obtained and evaluated image quality, CT numbers in middle cerebral artery, basilar artery; Noise; signal-to-noise ratio(SNR); and dose-length product(DLP), Effective dose(ED) were compared. ED was calculated from the DLP and a conversion factor (k=0,0021 mSv/mGy×cm). To qualitative image analysis, One observer indepen-dently assessed image quality using a 4-point scale. Independent t-test was used for quantitative and qualitative analysis, respectively. III. Result Significant difference in mean CT numbers of the middle cerebral artery and basilar artery was noted between the two groups(p=0.000). Noise of middle cerebral artery was significantly lower in the 320-MDCT group than in the 64-MDCT group(p=0.016). SNR of the both cerebrovasculars was significantly higher in the 320-MDCT group than in the 64-MDCT group(p=0.000). ED was 14% significantly lower in the 320-MDCT group than in the 64-MDCT group(p=0,000). Image quality was acceptable in both groups and was significantly better in the 320-MDCT group than in the 64-MDCT group(p=0,000). IV. Conclusions A 320-MDCT for brain CT angiography is a useful method for the diagnosis of cerebrovascular diseases with better image quality and lower radiation dose than 64-MDCT.

전산확단층검사에서 상지와 하지의 혈관조영검사를 위한 새로운 보조기구

권대철(Kweon Dae Cheol),권오성(Kwon Oh Sung),임흥선(Im Heung Seon),김명구(Kim Myeong Goo) 대한CT영상기술학회 2005 대한CT영상기술학회지 Vol.7 No.1

Purpose S표 immobilization of the patients is essential for diagnostic CT angiography. Our objective was to develop and evaluate a non-invasive device for rigid immobilization and surface disease non-contact of the 표 in the upper and lower extremity during CT angiography. Materials and Methods Patients undergoing CT examination during 8 months January to September 2004. 655 patients were evaluated with CT angiography. Upper limbs(n=41), Lower limbs(n=614) patients. Image quality in the infrapopliteal(lower limb), brachial region(upper limb). The patients upper limb device consists of a polyethylene resin which need to be immobilize is wrapped with up around the elbow joint area based vecro tape. Lower limb device stabilizing elements made of polyethylene resin soft materials, and pelvis parts foam pad is used for noncontact surface. In a prospective study the upper and lower extremity device was used in patients who underwent a CT angiography of the upper and lower limb. Results Immobilization with our device was well tolerated by all patients. The rigid immobilization resulted in a complete absence of motion artifacts. The device is well tolerated easy and quick to apply, and is now routinely used in limb angiography. During the examination the patients were explicitly asked about pain or any other discomfort, which all denied. The improvement in image quality was especially obvious in the patients who had undergone a previous CT examination without adequate immobilization. Conclusion The device immobilzation allows for comfor표, effective extremity immobilization during CT angiography resulting in complete absence of motion artifacts.

Dual Source CT에서 Coronary검사의 방사선량 비교분석

신용환(Yong Hwan Shin),안병환(Byoung Hwan Ahn),옥승호(Seung Ho Ock),권오성(Oh Sung Kwon),임흥선(Heung Seon IM),김명구(Myeong Goo Kim) 대한CT영상기술학회 2008 대한CT영상기술학회지 Vol.10 No.1

Purpose This Paper compared the Radiation Dose of Dual Source ECG-gating Spiral Scan and ECG-triggered Sequential Scan in coronary CT. and Analysed how much the Radiation dose reduced in sequential scan. Materials and Methods We studied Spiral and Sequential scan in Phantoms and used by Dual source MDCT called Definition. Scan was made as follows;(Spiral scan:Kvp/mAs/Rotation time/Pitch/Scan time/=100/320/0.33/0.28/8.82, Sequential scan: Kvp/mAs/Table feed/Cycle time/Scan time =100/180/20/1.37/8.22). We used ECG Simulator as equipment( NETECH) Contrast media diluted (CM :1, Normal saline:24) An Experimental method compared CIDivol and CIDIDlP with Spiral and Sequential scan and were measured. Qualitive analysis evaluate the CTDIvol, and CTDIDLP, and SNR through ROI analysis. Quantitative analysis evaluate the Uniformity and noise, Preference Results The results obtained as follows; Radiation dose reduced about 28.8% in Sequential scan than Spiral scan. SNR increased in Spiral scan than Sequential scan. The image Qualities with Sequential scan showed better than Spiral scan. Conclusion In conclusion, by comparing the Phantoms image with Spiral scan and Sequential Radiation dose reduced in Sequential scan. If used and selected properly Sequential scan useful clinically applied to the patients with coronary Disease. (Heart Rate <60-65bpm)

하지 64 MDCT 혈관조영술에서 outrun 예방을 위한 검사방법

안병환(Byoung Hwan Ahn),옥승호(Seung Ho Ock),김순자(Soon Za Kim),권대철(Dae Cheol Kweon),권오성(Eun Kyoung Lee),이은경(Oh Seong Kweon),임흥선(Heung Seon Im),김명구(Myeong Goo Kim) 대한CT영상기술학회 2007 대한CT영상기술학회지 Vol.9 No.1

Purpose In present, MDCT has come into wide use. But outrun often occurs due to fast scanning and rotation time in lower extremity CT angiography with-64 MDCT. We studied the prevention to outrun in lower extremity CT angiography. Materials and Methods Between October 2006 and January 2007, during a period of 4 months, total 210 patients underwent a lower extremity CT angiography with 64 channel MDCT. We scanned patients from the level of lumber-spine three to feet in a single helical scan with 64 MDCT. Examination was scanned by each of different scanning methods. We changed the scan parameter in 3 ways. First, we set the delay time to 6.4 sec and the rotation time to 1sec. We called it to PG 1 (aorta slow). Second, we set the delay time to 20 sec and the rotation time to 0.4 sec. We called it PG 2 (aorta fast). Third method was same as PG 1 except of setting triggering level to popliteal artery. It was called for PG 3 (popliteal fast). The data from scanning was transmitted to 3D software program. Three-dimensional images were obtained using MIP(maximum intensity projection). Four radiologist evaluated all the results in reference to outrun, vein contamination, motion artifact and enhancement of vessel. Results In PG 1, there was no outrun. But it had some vein contamination and motion artifact because of long scan time. In PG 2, there was some outrun. But it had hardly vein contamination and motion artifact due to fast scan time. In PG 3, there was no outrun, too On the a:her hand, it had some vein contamination. Conclusion The best way to prevent outrun is program one (PG 1) or program three (PG 3) in lower extremity CT angiography with 64 MDCT. But each method has inherently a merit and demerit. We should use the protocol which is fit to patient history.