藉由動態假體觀察冠狀動脈電腦斷層血管攝影的移動性假影特性

Observing the Characteristics of the Motion Artifact by Using Dynamic Phantom in Coronary Computed Tomographic Angiography

廖學鍵(Shueh-Chien Liao) ； 劉益瑞(Yi-Jui Liu) ； 陳郁芬(Yu-Fen Chen) ； 鄭偉宏(Wei-Hung Cheng) ； 魏世民(Shih-Min Wei) ； 吳新華(Xin-Hua Wu)

《中華放射線技術學雜誌》 37卷1期 (2013/03) Pp. 7-14

摘要

冠狀動脈電腦斷層血管攝影已對於冠狀動脈疾病的篩檢與診斷具有極佳優勢，可是移動性假影常常會損及影像品質，本研究希望藉由動態假體來瞭解移動性假影的特性。因此採用馬達式動態假體裝置進行研究，其運動速度設定為3.86 mm/sec到29.32 mm/sec等速變化，在此動態假體上固定五條不同直徑的熱縮管，來模擬冠狀動脈血管的顯影，其直徑各別為1.0 mm、1.5 mm、2.0 mm、2.5 mm、3.0 mm作為主要影像分析之對象。將動態假體放置於六十四列電腦斷層中，且選用冠狀動脈攝影條件進行掃描。研究結果顯示平均電腦斷層值在6.37 mm/sec以上的速度，就讓所有血管全都出現變化，至於有效面積則是要在11.09 mm/sec以上的速度才能讓全都血管出現變化，而大直徑模擬血管產生影像變化的速度較小直徑模擬血管來得高。影像分析中觀察到電腦斷層值與速度成反向的關係，而顯影面積則是正向的關係，因此移動性假影會導致電腦斷層值降低與顯影面積增加的特性。移動性假影的影響將取決於電腦斷層的時間解析度的能力，本研究的動態假體期許未來可作為檢測電腦斷層的時間解析度之參考工具。

關鍵字

時間解析度 ； 移動性假影 ； 動態假體

並列摘要

Coronary computed tomographic Angiography has the excellent advantage of screening and diagnosis of coronary artery disease. But the image quality usually hurt by the motion artifacts. We try to find out the characteristics of motion artifacts through dynamic phantom. In this study, the motor dynamic phantom is used and its velocity is set to 3.86 mm/sec to 29.32 mm/sec with constant change in velocity. Five simulated coronary arteries ,diameter are 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, fixed on the dynamic phantom are the main objects of this analysis. This Dynamic phantom is placed in the sixty-four Multidetectors computed tomography and scanned by the condition of angiographic image. The results show that image of 5 vessels will change at the average computed tomography number in 6.37 mm/sec or more, and at the effective area in the 11.09 mm/sec or more. Furthermore, the changes of image in large-diameter are faster than those in smaller diameter. We observed an inverse relationship between the computed tomography number and the change of image but a positive relationship to the effective area. For this reason, motion artifact will lead to the decrease of computed tomography number and the increase in effective area. The effects of motion artifacts depend on the temporal resolution in computed tomography. We wish that dynamic phantom can be used as a reference device in detecting the temporal resolution of computed tomography.

並列關鍵字

Temporal resolution ； Motion artifact ； Dynamic phantom