Contrast Media in Abdominal Computed Tomography: Optimization of Delivery Methods

Joon Koo Han,Byung Ihn Choi,Ah Young Kim,Soo Jung Kim The Korean Society of Radiology 2001 Korean Journal of Radiology Vol.2 No.1

Objective: To provide a systematic overview of the effects of various parameters on contrast enhancement within the same population, an animal experiment as well as a computer-aided simulation study was performed. Materials and Methods: In an animal experiment, single-level dynamic CT through the liver was performed at 5-second intervals just after the injection of contrast medium for 3 minutes. Combinations of three different amounts (1, 2, 3 mL/kg), concentrations (150, 200, 300 mgI/mL), and injection rates (0.5, 1, 2 mL/sec) were used. The CT number of the aorta (A), portal vein (P) and liver (L) was measured in each image, and time-attenuation curves for A, P and L were thus obtained. The degree of maximum enhancement (Imax) and time to reach peak enhancement (Tmax) of A, P and L were determined, and times to equilibrium (Teq) were analyzed. In the computed-aided simulation model, a program based on the amount, flow, and diffusion coefficient of body fluid in various compartments of the human body was designed. The input variables were the concentrations, volumes and injection rates of the contrast media used. The program generated the time-attenuation curves of A, P and L, as well as liver-to-hepatocellular carcinoma (HCC) contrast curves. On each curve, we calculated and plotted the optimal temporal window (time period above the lower threshold, which in this experiment was 10 Hounsfield units), the total area under the curve above the lower threshold, and the area within the optimal range. Results: A. Animal Experiment: At a given concentration and injection rate, an increased volume of contrast medium led to increases in Imax A, P and L. In addition, Tmax A, P, L and Teq were prolonged in parallel with increases in injection time The time-attenuation curve shifted upward and to the right. For a given volume and injection rate, an increased concentration of contrast medium increased the degree of aortic, portal and hepatic enhancement, though Tmax A, P and L remained the same. The time-attenuation curve shifted upward. For a given volume and concentration of contrast medium, changes in the injection rate had a prominent effect on aortic enhancement, and that of the portal vein and hepatic parenchyma also showed some increase, though the effect was less prominent. A increased in the rate of contrast injection led to shifting of the time enhancement curve to the left and upward. B. Computer Simulation: At a faster injection rate, there was minimal change in the degree of hepatic attenuation, though the duration of the optimal temporal window decreased. The area between 10 and 30 HU was greatest when contrast media was delivered at a rate of 2 3 mL/sec. Although the total area under the curve increased in proportion to the injection rate, most of this increase was above the upper threshould and thus the temporal window was narrow and the optimal area decreased. Conclusion: Increases in volume, concentration and injection rate all resulted in improved arterial enhancement. If cost was disregarded, increasing the injection volume was the most reliable way of obtaining good quality enhancement. The optimal way of delivering a given amount of contrast medium can be calculated using a computer-based mathematical model.

다중시기 조영증강 액체감쇠역전회복 자기공명영상은 작은 뇌전이의 발견에도움이 되는가?

김정환,이경식,최치훈,우승태,차상훈 대한영상의학회 2018 대한영상의학회지 Vol.78 No.3

Purpose: To determine adequate timing of acquisition of contrast-enhanced fluid attenuated inversion recovery (FLAIR) by using multiphasic contrast-enhanced FLAIR magnetic resonance imaging (MRI) and to evaluate added value in detecting small intracerebral metastases 5 mm or less. Materials and Methods: Twenty-nine patients, that underwent multiphasic contrast- enhanced FLAIR MRI and contrast-enhanced T1 weighted image (T1WI) were included and total number of small intracerebral metastases was 131. Sensitivity, specificity and accuracy of lesion detection were evaluated. Contrast ratio (CR) and enhancement ratio of each lesion were compared and analyzed among each imaging sequence. Results: Sensitivity, specificity and accuracy of lesion detection were increased when contrast-enhanced FLAIR was added to contrast-enhanced T1WI. Area of under receiver operating characteristic curve significantly increased by addition of contrast-enhanced FLAIR than using contrast-enhanced T1WI alone (p < 0.05). CR was significantly higher in contrast-enhanced T1WI than FLAIR (p < 0.001). All of the above results were not different according to time of acquisition of contrastenhanced FLAIR. Conclusion: There was advantage of conducting contrast-enhanced FLAIR MRI, but multiphasic contrast-enhanced FLAIR did not provide additional information for detection of small intracerebral metastases compared with single-phase FLAIR MRI. 목적: 다중시기 조영증강 액체감쇠역전회복(fluid attenuated inversion recovery; 이하 FLAIR) 자기공명영상을 이용하여5 mm 이하의 작은 뇌전이를 발견하는 데 가장 적절한 영상 획득 시기를 규명하고 부가적인 가치가 있는지 평가하고자 하였다. 대상과 방법: 조영증강 T1강조영상과 더불어 이중시기 혹은 삼중시기 조영증강 FLAIR영상을 시행한 환자 중 5 mm 이하의 뇌전이가 발견된 29명의 환자에게서 발견된 총 131개의 병변을 대상으로 뇌전이의 발견율, 명암비와 조영증강비를구하여 각 영상 검사별 차이를 분석하였다. 결과: 조영증강 T1강조영상만을 단독으로 시행했을 때보다 조영증강 FLAIR영상을 추가로 시행했을 때 뇌실질 전이 발견의 민감도, 특이도, 정확도가 증가하는 경향을 보였으나 조영증강 FLAIR영상의 획득 시기별 차이는 없었다. Receiver operating characteristic 커브의 커브아래면적도 조영증강 FLAIR영상을 추가로 시행했을 때 그 값이 유의하게 증가하였다(p < 0.05). 뇌전이 병변의 명암비는 조영 후 FLAIR영상에서 유의하게 높았고(p < 0.001), 조영증강비는 조영증강 T1 강조영상에서 유의하게 높았으나(p < 0.001) 조영증강 FLAIR영상의 획득 시기별 병변의 명암비와 조영증강비에는 차이가 없었다. 결론: 조영증강 FLAIR영상은 작은 뇌전이 발견에 부가적인 가치가 있지만 다중시기 조영증강 FLAIR영상별 차이는 없었다.

수술 후 요추 추간판 탈출증에서 역동적 조영증강 자기공명영상의 유용성

남지은 대한영상의학회 1999 대한영상의학회지 Vol.40 No.2

Purpose : To compare the usefulness of dynamic contrast enhanced lumber spine MR Imaging with that ofconventional delayed contrast enhanced MR imaging in the assessment of postoperative herniated lumbar disc.Materials and Methods : Forty-one postoperative herniated lumbar disc (HLD) lesions of 32 patients with back painwere examined with MR imaging(1.5T, Vision, Siemens, Germany). Five-phase dynamic 2D FLASH sagittalimages(TR/TE=118.1 msec) was obtained every 19 seconds with a 4 minutes delayed image after contrast injection. Asseen on delayed images, the discs were assessed as recurred, fibrosis, or no change. On dynamic images, thepattern of enhancement was evaluated as follows : Type I(no change in peripheral disc enhancement between theearly and late phase);or Type II(minimal internal extension of marginal smooth enhancement during the latephase);or Type III(marked internal extension f peripheral irregular enhancement). Dynamic and delayed imaging werecompared, and early epidural space enhancement with rapid wash-out was also evaluated. Results : of 41postoperative HLDs, 39 lesions showed peripheral contrast enhancement. Evaluation depended on delayed imaging, andwas as follows:recurred HLD(n=27);fibrosis(n=5);no change in postoperative disc(n=7). On dynamic contrast-enhancedimaging, enhancement patterns were Type I(n=29), Type II(n=7), and Type III(n=3). In 29 Type-I lesions, there wereno significant differences in image findings between dynamic and delayed images. However, in the lesions(typeII:n=7, type III:n=3), findings additional to those revealed by delayed images were demonstrated by dynamiccontrast-enhanced MR imaging. Nine of the ten Type-II and III lesions were diagnosed as recurred HLD. On dynamicOn dynamic images, five lesions showed early epidural space enhancement. Conclusion : dymamic contrast-enhancedlumbar spine MR imaging provided additional findings such as increased peripheral disc enhancement, and epiduralspace enhancement, which cannot be detected on conventional delayed images. Inrecurred postoperative herniatedlumbar discs, these findings are frequent.

Contrast 향상을 위한 가중치 맵 기반의 Retinex 알고리즘

이상원(SangWon Lee),송창영(ChangYoung Song),조성수(SeongSoo Cho),김성일(SeongIhl Kim),이원석(WonSeok Lee),강준길(JuneGill Kang) 大韓電子工學會 2009 電子工學會論文誌 IE (Industry electronics) Vol.46 No.4

최근에 널리 보급되고 있는 디지털 카메라는 제한된 크기의 Dynamic Range를 갖는 이미지 센서의 한계로 인하여 Dynamic Range가 넓은 환경에서 영상을 획득하면 인간의 눈으로 보는 것과는 달리 밝게 포화된 영상 또는 노출이 적은 어두운 영상을 얻게 된다. 입력 영상의 Dynamic Range를 압축하고 Contrast를 개선하기 위한 여러 가지 디지털 영상 처리 방법들 중에서 인간의 시각모델을 기반으로 한 Retinex 알고리즘은 Contrast 향상 및 컬러 재현성에 있어서 매우 효과적인 방법으로 알려져 있다. 하지만, Retinex 알고리즘은 Dynamic Range가 넓은 환경에서 획득한 영상의 경우에 전역적인 Contrast는 증가하나 국부적인 Contrast가 오히려 감소하는 Contrast 불균형이 발생하는 문제가 있다. 이러한 문제를 개선하기 위해 본 논문에서는 Retinex 영상에서 에지 정보와 노출 정보를 추출하여 가중치 맵을 구성하고 이를 영상 합성과정에 적용하여 Contrast의 불균형을 개선하는 알고리즘을 제안한다. 실험 결과 영상의 비교와 수치 분석을 통해 제안된 알고리즘이 기존의 알고리즘에 비해 Contrast 향상 성능이 더 우수한 방법임을 확인하였다. The Image sensor of digital still camera has a limited dynamic range. In high dynamic range scenes, a picture often turns out to be underexposed or overexposed. Retinex algorithm based on the theory of the human visual perception is known to be effective contrast enhancement technique. However, it happens the unbalanced contrast enhancement which is the global contrast increased, and the local contrast decreased in the high dynamic range scenes. In this paper, to enhance the both global and local contrast, we propose the weight mapping retinex algorithm. Weight map is composed of the edge and exposure data which are extracted in the each retinex image, and merged with the retinex images in the fusion processing. According to the output picture comparing and numerical analysis, the proposed algorithm gives the better output image with the increased global and local contrast.

조영증강 $^{18}F$-FDG PET/CT가 이중에너지 X-선 흡수 계측법을 이용한 골밀도 및 체성분 측정에 미치는 영향

김성수,이선도,이남주,신용철,모은희,이춘호,Kim, Seong Su,Lee, Sun Do,Lee, Nam Ju,Shin, Yong Cheol,Mo, Eun Hee,Lee, Chun Ho 대한핵의학기술학회 2012 핵의학 기술 Vol.16 No.2

PET/CT에 사용되는 방사성의약품 FDG와 CT 조영제가 DXA를 이용하여 측정하는 BMC, BMD, TFM, LBM 등의 결과에 미치는 영향을 알아보고자 하였다. 2011년 12월부터 2012년 3월까지 본원 PET/CT를 시행한 환자 중 본 연구에 참여를 동의한 환자 총 22명을 대상으로 하였다. 실험은 두 집단으로 나누어 실험을 진행하였는데 첫 번째 집단은 17명으로 PET/CT 용 방사성의약품인 FDG 정맥 주사 전에 WB DXA를 시행한 다음 FDG 정맥주사 1시간 후 CT 조영제 사용 없이 PET/CT (Non-Contrast Enhancement $^{18}F$-FDG PET/CT)시행 후 즉시 다시 WB DXA를 진행하였다. 두 번째 집단은 총 5명으로 첫 번째 집단과 마찬가지로 FDG 정맥 주사 전 WB DXA를 시행한 다음 FDG 정맥 주사 1시간 후 CT 조영제 사용하여 PET/CT (Contrast Enhancement $^{18}F$-FDG PET/CT)시행 후 즉시 다시 WB DXA 진행하였다. 결과는 PET/CT 전 후 DXA에서 WB-BMC, WB-BMD, TFM 그리고 LBM 등을 측정하였고 각 항목의 변화율을 산출하여 비교하였다. Non-Contrast Enhancement $^{18}F$-FDG PET/CT 전 후의 골밀도 및 체성분의 변화율은 WB-BMC, +2.4%; WB-BMD, +1.8%; TFM, -6.8%; LBM, +2.2%였고 각 항목의 변화는 통계적으로 유의한 차이가 없었다. Contrast Enhancement $^{18}F$-FDG PET/CT 전 후의 변화율은 WB-BMC, +13.7%; WB-BMD, +9.3%; TFM, -34.1%; LBM, +13.6%였고 Contrast Enhancement $^{18}F$-FDG PET/CT 전과 후의 골밀도 및 체성분 측정치의 변화는 통계적으로 유의하였다. 본 연구에서 Non-Contrast Enhancement $^{18}F$ PET/CT 후에는 DXA 시행은 결과에 영향이 없어 가능할 것이라 생각되어지나 Contrast Enhancement $^{18}F$-FDG PET/CT검사 후에 시행한 DXA 검사의 결과는 신뢰도가 감소될 것으로 사료된다. Purpose : The effect of concomitant use of $^{18}F$-FDG and intravenous contrast agent (CA) on dual-energy X-ray absorptiometry (DXA), was rarely reported. We had investigated these potentially confounding effects. Materials and Methods : Twenty-two patients had undergone DXA before and immediately after $^{18}F$-FDG PET/CT scans. Two DXA and 1 PET/CT scans had performed within one-day. $^{18}F$-FDG PET/CT scans had been performed with CA in 17 patients and without CA in 5 patients. Whole body bone mineral content (BMC), whole body bone mineral density (BMD), total fat mass (TFM), and lean body mass (LBM) were measured by DXA scanner before and after the $^{18}F$-FDG PET/CT scans. Results : BMC, BMD, TFM and LBM had significantly affected by $^{18}F$-FDG PET/CT with CA (BMC, +13.7%, from $2061.3{\pm}393.7$ to $2343.4{\pm}373.3$; BMD, +9.3%, from $1.07{\pm}0.09$ to $1.17{\pm}0.08$; TFM, -34.1%, from $17052.1{\pm}4049.9$ to $11237.1{\pm}2990.3$; LBM, +13.6%, from $45834.5{\pm}5662.1$ to $52094.0{\pm}6335.4$). However, $^{18}F$-FDG PET/CT without CA had no effect on the measurement of DXA (BMC, +2.4%, from $2197.7{\pm}391.6$ to $2251.5{\pm}380.9$; BMD, +1.8%, from $1.13{\pm}0.09$ to $1.15{\pm}0.07$; TFM, -6.8%, from $14585.6{\pm}3455.9$ to $13591.3{\pm}4351.4$; LBM, +2.2%, from $47360.5{\pm}8381.8$ to $48441.1{\pm}8488.1$). Conclusion : The measurements of DXA are affected by using CA. However, DXA scans might be unaffected by the presence of $^{18}F$-FDG administered for PET/CT.

Optimized Adaptive Fuzzy based Image Enhancement Techniques

Taranbir Kaur,Ravneet Kaur Sidhu 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.1

Image enhancement plays an important role in vision applications. Recently much work is performed in the field of images enhancement. Many techniques have already been proposed up to now for enhancing the digital images. The overall objective of this proposed work is to evaluate the performance of existing image enhancement techniques like Histogram equalization, adaptive histogram equalization and Fuzzy image enhancement technique. It has been found that the value of contrast parameter ‘K’ in fuzzy method was taken statically as 128. To overcome this, to make contrast dynamic a new optimized fuzzy method have been proposed. Here different optimization techniques ACO, PSO and ABC have been used to optimize the contrast and the technique with best optimized contrast value is selected. The newest approach has the ability to boost the contrast in digital images in efficient manner by utilizing the histogram based fuzzy image enhancement algorithm with optimized Contrast value. The proposed technique is designed and implemented in MATLAB using image processing toolbox.

Gd-BOPTA 조영증강 자기공명영상에서 간의 조영증강 양상: 경변성 간과 정상 간의 비교

신상수,정용연,강형근,임효순,윤웅,서정진,박진균,Sin, Sang-Su,Jeong, Yong-Yeon,Gang, Hyeong-Geun,Im, Hyo-Sun,Yun, Ung,Seo, Jeong-Jin,Park, Jin-Gyun 대한영상의학회 2004 대한영상의학회지 Vol.50 No.1

목적:Gd-BOPTA 조영증강 자기공명영상의 지연기 영상에서 간경변 환자군과 정상군 사이에 간실질의 조영증강 양상의 차이를 비교하고자 하였다. 대상과 방법:Gd-BOPTA 조영증강 자기공명영상을 시행한 60명(간경변 환자군 35명, 정상군 25명)을 대상으로 하였다.1.5T 자기공명영상 기기에서 위상배열 다중코일을 사용하여 조영전과 Gd-BOPTA를 일시에 정맥 주입하고 60분 후에 in-phase와 opposed-phase T1강조 경사에코 영상을 각각 얻었다. 모든 영상은 다음과 같이 분석하였다. 정량적 분석은 간실질의 신호잡음비 (signal to noise ratio,이하 SNR)와 조영증강값 (signal enhancement,이하 SE)을 구하여, 간경변 환자군과 정상군 사이에 차이를 비교하였다. 간경변 환자군에서는 Child-Pugh분류에 따른 SNR과 SE의 차이를 비교하였다. 정성적 분석은 간의 조영증강 양상을 두 명의 방사선과의사가 합의하에 균질성과 비균질성으로 분류하였다. 결과:간실질의 SNR은 간경변 환자군 (p<0.001)과 정상군 (p<0.001)모두가 지연기 영상에서 조영전과 비교하여 유의하게 증가하였고,Gd-BOPTA 조영증강 in-phase(p<0.001)와opposed-phase(p<0.001)T1강조 경사에코 영상에서 간경변 환자군이 정상군에 비해 유의하게 낮았다. 경변성 간의 SE는 정상 간에 비해 유의하게 낮았다 (in-phase:p=0.002,opposed-phase:p=0.011). 경변성 간에서 간실질의 SNR은 Child-Pugh A군(p<0.001)과 B군(p<0.001)모두가 지연기 영상에서 유의하게 증가하였고, Gd-BOPTA 조영증강 in-phase(p<0.001)와 opposed-phase(p=0.022)T1강조 경사에코 영상에서 Child-Pugh A군이 B군에 비해 유의하게 높았다.SE는 in-phase T1강조 경사에코 영상에서 Child-Pugh A군이 B군에 비해 유의하게 높았다 (p=0.004).간경변 환자군에서는 35명중 20명(57%)에서 비균질성의 조영증강 양상을 보였지만,정상군에서는 모든 예에서 균질성의 조영증강 양상을 보였다. 결론:Gd-BOPTA 조영증강 자기공명영상의 지연기 영상에서 경변성 간은 정상 간에 비해 조영증강의 정도가 낮았으며,간경변 환자에서 간기능이 떨어질수록 조영증강의 정도가 낮았다. 따라서 Gd-BOPTA 조영증강 자기공명영상의 지연기 영상은 간기능의 보존정도를 평가하는데 도움을 줄 수 있을 것으로 생각된다. Purpose: To compare the enhancement features of hepatic parenchyma between cirrhotic and normal liver, using Gd-BOPTA-enhanced delayed MR imaging. Materials and Methods: The 60 patients (35 with cirrhotic and 25 with normal liver) included in our study underwent Gd-BOPTA-enhanced MR imaging using a 1.5T system with a phase-array multicoil. In all cases, T1-weighted in-phase and opposed-phase gradient-echo MR imaging was performed before and 60 minutes after intravenous administration of a bolus of Gd-BOPTA. All images were quantitatively analysed by comparing the signal-to-noise ratio (SNR) and signal enhancement (SE) of cirrhotic and normal liver before and after contrast enhancement, and in cirrhotic patients, SNR and SE were also compared in terms of the Child-Pugh classification. For qualitative analysis, the hepatic enhancement patterns of cirrhotic and normal liver were classified as homogeneous or heterogeneous according to the consensual findings of two radiologists. Results: At contrast-enhanced imaging, both cirrhotic (p<0.001) and normal liver (p<0.001) showed substantially increased SNR relative to unenhanced images, and the SNR of cirrhotic liver was significantly lower than that of normal livers at both in-phase (p<0.001) and opposed-phase (p<0.001) imaging. The SE of cirrhotic liver was significantly lower than that of normal liver (in-phase: p=0.002; opposed phase: p=0.011). Both Child-Pugh class A (p<0.001) and B (p<0.001) cirrhotic liver showed a substantial increase in SNR at contrast-enhanced imaging relative to unenhanced imaging and the SNR of Child-Pugh class A was significantly higher than that of Child-Pugh class B at both in-phase (p<0.001) and opposed-phase (p=0.022) imaging. In addition, the SE of class A was significantly higher than that of class B at in-phase imaging (p=0.004). Cirrhotic liver showed heterogeneous enhancement in 20 of 35 patients (57%), whereas normal liver showed homogeneous enhancement in all patients. Conclusion: At Gd-BOPTA-enhanced delayed MR imaging, cirrhotic liver showed less enhancement than normal liver. In cirrhotic patients, hepatic enhancement and hepatic function decreased in tandem. Gd-BOPTAenhanced delayed MR imaging may be useful for evaluating the functional reserve of the liver.

Hepatic CT Enhancement: Comparison between Dimeric and Monomeric Nonionic Contrast Agents in Rabbits

김기현,곽병국,심형진,김교남,유위강,유승훈,김양수,이종범,김건상,Kim, Gi-Hyeon,Kwak, Byung-Kook,Shim, Hyung-Jin,Kim, Kyo-Nam,Liu, Wei Chiang,Ryu, Seung-Hoon,Kim, Yang-Soo,Lee, Jong-Beum,Kim, Kun-Sang The Korean Radiological Society 2003 대한영상의학회지 Vol.48 No.6

목적: 정상 가토에서 비이온성 이중체(dimer)인 iodixanol과 단량체(monomer)인 ioversol간의 간과 대동맥에서의 조영증강 정도를 비교하고자 하였다. 대상과 방법: 나선식 CT를 이용하여 가토 7마리에서 일주일 간격을 두고 iodixanol(Visipaque 320, Nycomed, Oslo, Norway)과 ioversol(Optiray 320, Mallincrodt medical, Quebec, Canada)로 각각 3초간격으로 120초 동안 간의 한부위에서 역동적 CT를 시행하였다. 각 가토 체중에 따라 동일량의 조영제를 사용하였으며 2(ml/kg), 조영 증강치와 최고 조영 증강치에 도달하는 평균 시간을 산출한 후 조영증강 곡선을 구하였고, 두 조영제간의 차이를 통계학적으로 비교하였다. 결과: 간실질의 평균 조영 증강치는 후기 동맥기에서 조기 문맥기(18-39초)에 이르는 동안 ivorsol을 사용한 예에서 더 높게 관찰 되었으며 통계학적으로 의의가 있었다(P<0.05). 또한 간실질, 문맥, 대동맥에서의 평균 최고 조영 증강치 역시 ioversol을 사용한 예에서 더 높게 관찰되었다. 그러나, 최고 조영 증강치에 도달하는 평균시간은 두 조영제 사이에 유의한 차이가 관찰되지 않았다. 결론: Ioversol은 후기 동맥기에서 조기 문맥기에 이르는 동안 간실질의 조영증강에 있어 iodixanol보다 통계적으로 유의한 효과를 보였다. Purpose: To determine the hepatic and vascular enhancement profiles with nonionic dimeric, iodixanol, contrast agent in the rabbit and to compare them with nonionic monomeric, ioversol, contrast agent. Materials and Methods: Seven rabbits initially underwent hepatic dynamic CT scan with either iodixanol or ioversol, followed by repeated CT scan with other unused contrast agent with one week interval between scans. Pre and post contrast attenuation values of hepatic parenchyma, aorta and portal vein were measured sequentially. The mean enhancement of the hepatic parenchyma, aorta and portal vein were compared between two agents. The mean peak enhancement and peak enhancement time of the liver, aorta, and portal vein were also compared. Results: The attenuation values of ioversol showed a greater mean hepatic enhancement than iodixanol from 18 seconds to 39 seconds after injection (from late arterial phase to early portal venous phase) with a statistical significance (p<0.05). The mean peak enhancement of hepatic parenchyma, aorta and portal vein was also greater using ioversol than iodixanol, but the mean peak enhancement times of ioversol and iodixanol were nearly identical. Conclusion: Ioversol may have the greater effects than iodixanol on hepatic tumor conspicuity, especially from late arterial phase to early portal veneous phase.

Pretreatment assessment of tumor enhancement on contrast-enhanced computed tomography as a potential predictor of treatment outcome in metastatic renal cell carcinoma patients receiving antiangiogenic therapy

Han, Kyung Seok,Jung, Dae Chul,Choi, Hyuck Jae,Jeong, Min Soo,Cho, Kang Su,Joung, Jae Young,Seo, Ho Kyung,Lee, Kang Hyun,Chung, Jinsoo Wiley Subscription Services, Inc., A Wiley Company 2010 Cancer Vol.116 No.10

<B>BACKGROUND:</B><P>Tumor vascularity is a potential predictor of treatment outcomes in metastatic renal cell carcinoma (mRCC), and contrast enhancement of tumors in computed tomography (CT) is correlated significantly with microvessel density. In this study, the authors investigated whether tumor enhancement in contrast-enhanced CT (CECT) is useful for predicting outcomes in patients with mRCC who are receiving antiangiogenic therapy.</P><B>METHODS:</B><P>Attenuation values were reviewed retrospectively on CECT images of all metastatic lesions in 66 patients from February 2007 to November 2008. All patients received a tyrosine kinase inhibitor (either sunitinib or sorafenib). Tumor response was evaluated on CECT studies every 12 weeks. The authors analyzed the association between contrast enhancement and treatment outcomes, including objective response, tumor size reduction rate, time to response, and time to progression.</P><B>RESULTS:</B><P>In 46 patients, 198 metastatic lesions were assessed. Tumor size was reduced in 140 lesions (70.7%) and was increased in 58 lesions (29.3%). The mean reduction in size was 23.8%. The overall mean time to response and the time to progression were 8.6 months and 16.4 months, respectively. In multivariate analyses, tumor enhancement and enhancement pattern were associated with objective responses (P = .003 and P = .028, respectively). In addition, tumor enhancement was associated with tumor size reduction (P = .004). In Cox proportional hazards models, only tumor enhancement was associated significantly with the time to size reduction and progression-free survival (P = .03 and P = .015, respectively).</P><B>CONCLUSIONS:</B><P>Tumor enhancement on CECT images was associated with treatment outcomes and was identified as a potential predictor of treatment outcomes after antiangiogenic therapy in patients with mRCC. Cancer 2010. © 2010 American Cancer Society.</P>

조영증강 복부 CT 검사에서 조영제 사용량 감소에 관한 연구: 인공지능 기반 조영 증강 부스트 기술

양민재,한현석,이성주,이민수,조명주 대한CT영상기술학회 2024 대한CT영상기술학회지 Vol.26 No.1

본원에서는 일부 조영증강 복부 CT 검사 시 이중-선원 이중 에너지 CT의 저 에너지 가상 단색 영상(Virtual Monochromatic Image; VMI)을 이용하여 조영제 사용량 감소(체중×1.2 mL)를 임상 검사에 적용하고 있다. 이에, 최근 도입된 CE-Boost 기술을 적용해 표준 조영제 사용량(체중×1.6 mL) 120 kV 단일-선원 조영증강 복부 CT 영상과 비교 평가하여 표준 조영제 사용량을 사용하는 조영증강 복부 CT검사에서도 조영제 사용량 감소를 적용할 수 있는지 알아보고자 하였다. 2023년 1월부터 조영제사용량 감소를 적용한 실험군(A), 실험군+CE-Boost(B), 표준 조영제 사용량을 적용한 대조군(C)의 62명을 대상으로 후향적 연구를 진행하였다. 정량적인 평가를 위해 주문맥이 가장 넓게 보이는 영상에서 동맥기의 복부대동맥과 우측 척주기립근, 문맥기의 주문맥과 간실질, 우측 척주기립근에 관심영역(Region of Interest; ROI)을 설정하여 CT Number(HU), 신호 대 잡음비(Signal to Noise Ratio; SNR), 대조도 대 잡음비(Contrast to Noise Ratio; CNR)를 산출하였다. 정성적 평가는 10명의 영상을 표본으로 설정하여 조영증강 정도와 전반적인 영상의 질 평가 항목으로 숙련된 방사선사 5명이 독립적으로 평가하였다. HU 값은 CE-Boost 기술을 적용한 (B) 그룹이 가장 높은 값을 나타내었고,(P<.05) CE-Boost 기술이 적용되지 않은 (A)-(C) 그룹은 통계적으로 유의미한 차이를 보이지 않았다.(P>.05) SNR에서는 CE-Boost가 적용된 (B)그룹이 가장 높은 값을 나타냈으나,(P<.05) 간실질 부위 평가에서 CE-Boost 기술이 없는 (C)그룹과 유의미한 차이를 보이지 않았다.(P>.05) CNR에서도 CE-Boost 기술이 적용된 (B)그룹이 가장 높은 값을 나타냈으나,(P<.05) (B)-(C) 그룹 간에 통계적으로 유의미한 차이를 보이지 않았다.(P>.05) 정성적 평가에서도 CE-Boost가 적용된 (B)그룹이 평가 항목 2문항에서 가장 우수한 것으로 평가되었다.(P<.05) 조영증강 복부 CT 검사 시 인공지능기반의 CE-Boost 기술을 이용한다면 이중-선원 이중 에너지 CT가 아닌 단일-선원 120kV CT 검사에서도 영상의 질을 유지하면서 표준 조영제 사용량의 약 25% 감소를 적용할 수 있어 환자에게 더 안전한 의료 서비스를 제공할 수 있을 것으로 생각된다. In our hospital, we implement a reduction in contrast media dose (calculated as body weight × 1.2 mL) for clinical examinations conducted with dual-source dual-energy CT during contrast-enhanced abdominal CT examinations. Therefore, by applying the CE-Boost technique, the degree of contrast enhancement of blood vessels and tissues was compared with standard contrast media dose (body weight × 1.6 mL) in 120 kV single-source computed tomography images. In contrast-enhanced abdominal CT using the standard contrast media dose, the CE-Boost technique was applied to investigate the feasibility of reducing the contrast media dose. From January 2023, a retrospective study was conducted on 62 subjects. The study included an experimental group (A) that received a reduced contrast media dose, an experimental group + CE-Boost (B), and a control group (C) that received the standard contrast media dose. For quantitative evaluation, in the image where the Main Portal Vein (MPV) is the widest, CT number (HU), Signal-to-Noise Ratio (SNR), and Contrast-to-Noise Ratio (CNR) were calculated. Qualitative evaluation was independently assessed by five experienced radiotechnologists, who evaluated 10 samples as the assessment items for contrast enhancement and overall image quality. In the HU values, the (B) group with CE-Boost technique showed the highest value (P < .05), while the (A)-(C) group without CE-Boost technique showed no statistically significant difference. In the SNR, the group (B) that received the CE-Boost technique exhibited the highest value,(P<.05) but there was no significant difference compared to the group (C) that did not receive the CE-Boost technique in the evaluation of liver parenchyma.(P>.05) In CNR, the (B) group utilizing the CE-Boost technique showed the highest value (P<.05), but there was no statistically significant difference between (B) and (C). In the qualitative evaluation, the group (B) to which CE-Boost was applied was rated the highest in two evaluation items. If an AI-based CE-Boost technique is used for contrast-enhanced abdominal CT, it is believed that safe medical services can be provided to patients by implementing a 25% reduction in the standard contrast media dose while still maintaining image quality, even in a single-source 120kV CT.