저선량 CT에서 다양한 촬영기법에 따른 폐결절의 석회화 발견과 음영도 변화의 팬텀 연구
A Phantom Study for Attenuation Change and Detection of Calcification in Lung Nodules According to Variation of Examination Techniques in Low Dose CT
- 주제(키워드) Low-dose chest CT , Lung phantom , Lung nodule , CT densitometry
- 발행기관 아주대학교
- 지도교수 박경주
- 발행년도 2016
- 학위수여년월 2016. 2
- 학위명 석사
- 학과 및 전공 일반대학원 의학과
- 실제URI http://www.dcollection.net/handler/ajou/000000022113
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Purpose : To evaluate the attenuation change of hyperdense lung nodule and diagnostic performance of visual assessment according to various tube voltage and current setting in low-dose CT comparing with standard-dose CT. Material and Methods : A chest phantom containing artificial nodules was scanned with 64-detector-row and 128-detector-row CT scanners using a standard and various low-dose settings with iterative reconstruction. Mean attenuation of nodules and image noise were compared between the standard-dose and low-dose images. Diagnostic accuracy of visual assessment by two readers for discrimination of hyperdense nodule was analyzed using CT images of standard and 5 selected low-dose settings. Results : Mean CT attenuation of nodules was increased with low tube voltage and image noise was increased with low tube voltage and current in both CT scanners. Mean attenuation of some nodules below hyperdense criteria (200 HU) on standard-dose CT was changed to considerably above 200 HU on low tube current and voltage setting. Diagnostic accuracy for discrimination of hyperdense nodule by visual assessment was not different between standard-dose and low-dose CT scans. Inter-observer agreement for grading of hyperdense nodule showed better agreement in higher radiation-dose scans. Conclusion : Low-dose CT maintains the diagnostic accuracy in visual assessment of hyperdense lung nodule despite increased image noise and higher attenuation criteria will be necessary for determining hyperdense nodule using CT densitometry in low-dose setting.
more목차
Ⅰ. INTRODUCTION 1
Ⅱ. MATERIAL AND METHODS 3
A. Anthropomorphic Phantom and Artificial Nodules 3
B. CT Imaging 10
C. Image Analysis 10
D. Statistics 12
Ⅲ. RESULTS 13
A. CT Attenuation of Artificial Nodules 13
B. Visual Assessment and Interobserver Correlation 17
Ⅳ. DISCUSSION 20
Ⅴ. CONCLUSION 30
REFERENCE 31
국문요약 34
