64切與256切電腦斷層血管攝影於冠狀動脈繞道術後評估之輻射劑量與影像品質研究

Comparison of 64- and 256-Slice CT of Radiation Dose and Image Quality in Coronary Artery Bypass Grafts

陳良光(Liang-Kuang Chen)；呂坤木(Kun-Mu Lu)；蘇誠道(Cheng-Tau Su)；李正輝(Cheng-Hui Lee)；羅偉業(Wei‐Yip Law)；盧建利(Chien-Li Lu)；蔡裕豐(Yuh-Feng Tsai)

電腦斷層冠狀動脈攝影 ； 冠狀動脈繞道手術 ； 回顧性心電閘控掃描 ； 前瞻性心電閘控掃描 ； CT coronary angiography (CTCA) ； coronary artery bypass graft (CABG) ； retrospectively gated helical (RGH) scan technique ； prospectively gated axial (PGA) scan technique

中華放射線技術學雜誌

39卷3期（2015 / 09 / 01）

159 - 166

繁體中文

冠狀動脈疾病(coronary artery disease, CAD)患者在接受冠狀動脈繞道手術(coronary artery bypass graft, CABG)後，通常須接受術後檢查和長期追蹤(follow-up)，以評估血管狀態與預後。本研究目的為使用64切回顧性(64 CT-RGH)與256切回顧性(256 CT-RGH)與256切前瞻性(256 CT-PGA)心電閘控掃描技術等不同掃描技術，針對受試者族群特性、掃描參數、輻射劑量和影像品質進行比較與探討。本研究共分析82位病人之207 條繞道血管和972 段繞道血管節段，並對繞道血管的影像品質使用五等級評分，從1 分(最佳)到5 分(無法診斷)評估每節段之影像品質並與輻射劑量進行比較。結果顯示256 CT-PGA 相對於64CT-RGH，平均可減少高達72%的有效劑量，256 CT-RGH 相對於64 CT-RGH，平均可減少16%的有效劑量(64 CT-RGH, 31.8 ± 5.8mSv; 256 CT-RGH, 26.7 ± 5.0 mSv; 256 CT-PGA, 8.8 ± 1.6mSv)，並有較佳的影像品質(64 CT-RGH, 2.4 ± 0.7; 256 CT-RGH, 1.7 ± 0.6; 256 CT-PGA, 1.6 ± 0.6)。而比較256 切CT 冠狀動脈攝影之RGH和PGA 兩種不同掃描技術，PGA不僅劑量低且影像品質佳，顯示此三種掃描技術於CABG術後追蹤，256CT-PGA具有較低之輻射劑量與良好之影像品質。

To assess the vascular status and prognosis, the patients of coronary artery disease (CAD) are subjected to inspection and long-term follow up after coronary artery bypass grafts (CABG) surgery. The purpose of this study is to compare radiation dose and image quality of computed tomography coronary angiography (CTCA) with 64 slice-retrospective gated helical CT (64 CT-RGH), 256 slice-retrospective gated helical CT (256 CT-RGH), and 256 slice-prospective gated axial (256 CT-PGA) in assessing coronary artery bypass grafts. This study analyzed 207 grafts with 972 segments in 82 patients who received CTCA. The image quality of the bypass grafts was assessed by a 5-point scale (1 = excellent to 5 = non-diagnostic) for each segment (proximal anastomosis, proximal, middle, distal course of graft body, and distal anastomosis) and was compared with each radiation dose. The results show that 256-CT PGA is associated with a 72% reduction in effective radiation dose as compared to 64 CT-RGH, and 256-CT RGH is associated with a 16% reduction in effective radiation dose as compared to 64 CT-RGH (64 CT-RGH, 31.8 ± 5.8 mSv; 256 CT-RGH, 26.7 ± 5.0 mSv; 256 CT-PGA, 8.8 ± 1.6 mSv), and has better image quality (64 CT-RGH, 2.4 ± 0.7; 256 CT-RGH, 1.7 ± 0.6; 256 CT-PGA, 1.6 ± 0.6). PGA scan technique is superior to RGH scan technique in reducing the effective dose and has better image quality on 256-slice CT CTCA. In conclusion, following bypass surgery, 256 CT-PGA is superior to 64 CT-RGH and 256 CT-RGH technique, and has lower radiation dose and better image quality of bypass grafts.