[논문]나선형영상획득에서 Pitch에 따른 CT 감약계수와 잡음의 변화

강성진

doi:10.7742/jksr.2020.14.7.981

나선형영상획득에서 Pitch에 따른 CT 감약계수와 잡음의 변화
Changes in CT Number and Noise Level according to Pitch in Spiral Image Acquisition 원문보기

한국방사선학회 논문지 = Journal of the Korean Society of Radiology, v.14 no.7, 2020년, pp.981 - 989

강성진 (안산대학교 방사선학과)

초록
AI-Helper

본 연구는 Pitch의 변화에 따른 CT 감약계수(CT Number)와 잡음(Noise)의 변화를 정량적으로 측정하고자 자체 제작한 맞춤형 팬텀(Customized Phantom)을 사용하였다. 팬텀을 이용한 영상의 획득을 위해 팬텀 내부는 멸균증류수로 가득 채웠다. 유리관 내부에는 생리식염수와 조영제의 비율을 각각 생리식염수 100%, 400:1, 200:1, 100:1, 50:1로 희석한 용액을 담은 후 영상화하였고, 이때 용액의 희석비율별로 pitch를 0, 0.35, 0.7, 1.05, 1.4의 단계로 나누어 각각 영상화하였다. 희석비율별로 모든 ROI에서 측정한 CT number와 noise 값의 평균이 pitch의 변화에 따라 유의한 차이를 보이는지 검증하고자 일원 배치 분산분석(One-way ANOVA Analysis)과 사후검정을 시행하였다. 실험 결과 각 희석비율별 pitch의 변화에 대한 CT number의 변화는 통계적으로 유의한 차이가 없었지만, noise 값은 pitch의 증가에 따라 증가하는 경향을 보였으며, 통계적으로도 유의한 차이를 보이는 것으로 나타났다. 나선형 영상획득 방식은 pitch에 따라 noise가 유의한 수준으로 달라질 수 있다. 따라서 나선형 영상획득 방식을 적용한 CT 영상의 화질평가 항목과 기준을 설정할 필요가 있을 것이다.

Abstract ▼ AI-Helper

In this study, a self-made customized phantom was used to quantitatively measure the change in CT number and noise according to the change of pitch. In order to acquire an image using the phantom, the inside of the phantom was filled with sterile distilled water. Inside the glass tube, a solution obtained by diluting the ratio of normal saline and contrast medium to 100%(NS), 400:1, 200:1, 100:1, 50:1, respectively, was placed and imaged. At this time, the pitch was divided into steps of 0, 0.35, 0.7, 1.05, and 1.4 for each dilution ratio of the solution and imaged, respectively. One-way ANOVA analysis were performed to verify whether the mean of the CT number and noise values measured in all ROIs by dilution ratio showed a significant difference according to the change in pitch. As a result of the experiment, there was no statistically significant difference in the change of the CT number according to the change in the pitch for each dilution ratio, but the noise value tended to increase with the increase of the pitch, and showed a statistically significant difference. In the spiral image acquisition of CT, noise can be changed to a significant level depending on the pitch. Therefore, it will be necessary to set the quality evaluation items and criteria for CT images using the spiral image acquisition method.

주제어

표/그림 (10)

그림 Fig. 1. Schematic drawing of customized CT phantom made for the experiment.
그림 Fig. 2. Photograph of customized CT phantom used in the experiment.
그림 Fig. 3. Setting the region of interest(ROI) on the acquired image for measuring CT number and noise.
표 Table 1. Average value of CT number and noise measured at all ROIs according to dilution ratio and pitch factor.
표 Table 2. Results of one-way ANOVA analysis of changes in CT number and noise according to pitch factor.
그림 Fig. 4. Variation of CT number(left) and noise(right) according to pitch in 100 % normal saline.
그림 Fig. 5. Variation of CT number(left) and noise(right) according to pitch in 400:1(normal saline: iodine contrast material) diluted solution.
그림 Fig. 6. Variation of CT number(left) and noise(right) according to pitch in 200:1(normal saline: iodine contrast material) diluted solution.
그림 Fig. 7. Variation of CT number(left) and noise(right) according to pitch in 100:1(normal saline: iodine contrast material) diluted solution.
그림 Fig. 8. Variation of CT number(left) and noise(right) according to pitch in 50:1(normal saline: iodine contrast material) diluted solution.

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상세보기

표제어: PCR

동의어: Packet Collision Rate

용어 설명 출처 목록 (6)

용어 설명: PCR은 세균 특이성이 있는 primer를 이용하여 적은 수의 세균이 있을지라도 쉽게 검출할 수 있는 유용한 방법이며, 이를 이용하여 구강 내 치면세균막이나 타액에서 직접 세균을 검출할 수 있게 되었다[8].

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