Journal of the Korean Society of Radiology (대한영상의학회지)

The Korean Society of Radiology (대한영상의학회)
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Use of Iterative Reconstruction and a Small Contrast Volume in Rabbit Kidney CT: Comparison with Conventional Protocol

반복적 재구성 기법과 저용량 조영제를 이용한 토끼 신장 CT: 기존 영상과의 비교연구

  • Kim, Rihyeon (Department of Radiology, Seoul National University Hospital) ;
  • Kim, Sang Youn (Department of Radiology, Seoul National University Hospital) ;
  • Cho, Jeong Yeon (Department of Radiology, Seoul National University Hospital) ;
  • Lee, Joongyub (Medical Research Collaborating Center, Seoul National University Hospital) ;
  • Kim, Seung Hyup (Department of Radiology, Seoul National University Hospital)
  • 김리현 (서울대학교병원 영상의학과) ;
  • 김상윤 (서울대학교병원 영상의학과) ;
  • 조정연 (서울대학교병원 영상의학과) ;
  • 이중엽 (서울대학교병원 의학연구협력센터) ;
  • 김승협 (서울대학교병원 영상의학과)
  • Received : 2017.10.16
  • Accepted : 2018.04.21
  • Published : 2018.08.01
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Abstract

Purpose: To investigate the quality of rabbit kidney computed tomography (CT) images obtained using a small contrast volume and iterative reconstruction (IR). Materials and Methods: Twenty sedated rabbits were used. Four milliliters of contrast material and the IR technique were used for the study group. In the control group, 6 mL of contrast and the filtered back projection (FBP) technique were used. The image quality was evaluated by two radiologists in consensus. For qualitative image assessment, the sharpness, noise, texture, and streak artifacts were rated. For quantitative analysis, the CT attenuation values, image noise, signal-to-noise ratios (SNR), contrast-to-noise ratios (CNR), and figures of merit (FOM) were calculated. Results: Images obtained from the study group were sharper and contained less noise and fewer streak artifacts (all, p < 0.05) compared to those obtained from the control group. However, the texture of images from the study group was worse (p < 0.05). Although the CT attenuation values were comparable between the study and control groups, the image noise was considerably lower for the study group than that for the corresponding control group (all, p < 0.05). Thus, the SNR, CNR, and FOM were higher in the study group (all, p < 0.05) than in the control group. Conclusion: The use of the IR technique and a small volume of contrast material yielded CT images with better qualities compared to those obtained using the FBP technique and conventional contrast volume in a rabbit model.

목적: 본 연구에서는 반복적 재구성 기법과 저용량 조영제를 사용한 토끼 신장 CT 영상의 질을 비교 평가하고자 하였다. 대상과 방법: 실험에 사용된 토끼는 총 20마리로서, 실험군에서는 4 mL의 조영제와 반복적 재구성 기법을 적용하였고, 대조군에서는 6 mL의 조영제와 여과 역투사법을 이용하였다. CT영상의 질 평가는 2명의 비뇨영상의학 전문의의 합의로 이루어졌다. 4점 척도로 영상의 선예도, 영상 잡음, 영상 질감, 줄무늬 인공물의 4가지 항목을 정성적으로 평가하였다. 정량적 평가 항목으로는 평균 CT 감쇄 값, 영상 잡음, 신호 대 잡음비, 대조도 대 잡음비 및 성능 지수를 계산하였다. 결과: 정성적 비교 평가 결과, 실험군에서 유의하게 영상 잡음과 줄무늬 인공물이 적었고 보다 나은 영상의 선예도를 보여 주었다(p < 0.05). 하지만, 영상의 질감은 실험군에서 오히려 떨어졌다(p < 0.05). 평균 CT 감쇄 값은 실험군과 대조군이 비슷하였지만 실험군에서 영상 잡음이 현저하게 낮아 신호 대 잡음비, 대조도 대 잡음비 및 성능 지수 모두 대조군에 비해 유의하게 높은 값을 보였다(p < 0.05). 결론: 4 mL 조영제와 반복적 재구성 기법을 적용한 토끼 신장 CT는 기존의 6 mL 조영제와 여과 역투사법을 사용한 CT 보다 나은 영상의 질을 보여주었다.

Keywords

Acknowledgement

Supported by : Seoul National University Hospital

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