64及256切小兒心臟電腦斷層於不同造影模式之影像品質與輻射劑量的探討

Investigation of Radiation Dose and Image Quality in Pediatric Cardiac Imaging: Comparison of 64- and 256-Slice CT

呂坤木(Kun-Mu Lu) ； 紀卓永倫(Yung-Lun Chi Cho) ； 蔡裕豐(Yuh-Feng Tsai) ； 李正輝(Cheng-Hui Lee) ； 盧建利(Chien-Li Lu) ； 陳良光(Liang-Kuang Chen)

《中華放射線技術學雜誌》 41卷3期 (2017/09) Pp. 123-130

摘要

多排偵檢器電腦斷層掃描儀目前已可廣泛應用於成人心臟冠狀動脈檢查，然而，在小兒心臟檢查運用上，仍面臨許多困難。小兒心臟體積較小、心跳速度較快，臨床不確定性較多，故需更高階的多排偵檢器電腦斷層掃描儀來協助取像判讀。鑑於目前尚未有完整的256 切電腦斷層掃描儀應用於小兒心臟冠狀動脈檢查之研究，本研究使用臨床一歲及五歲小兒心臟電腦斷層檢查於無心電閘控掃描技術、回溯性心電閘控掃描技術與前瞻式心電閘控掃描技術之造影參數，運用於256 切電腦斷層掃描儀上，配合美國放射學院電腦斷層認證假體使用，評估256 切電腦斷層掃描儀於小兒心臟檢查的輻射劑量及影像品質影響，同時將相同的造影參數轉移到臨床64 切電腦斷層掃描技術上，探討不同排數電腦斷層掃描儀於小兒心臟檢查之影像品質及輻射劑量差異。研究結果顯示，使用心電閘控掃描技術時，前瞻式心電閘控掃描技術會比回溯性心電閘控掃描技術有更低的輻射劑量，且維持良好之影像品質，但缺點是前瞻式心電閘控掃描技術時間解析度較低，無法記錄整個心週期影像。無心電閘控掃描技術的輻射劑量則介於前瞻式心電閘控掃描技術與回溯性心電閘控掃描技術之間，影像雜訊最低，但時間解析度最低且無法同步心週期是其缺點。總體而言，不論使用一歲或五歲之小兒心臟電腦斷層造影參數，256 切前瞻式心電閘控掃描技術比起回溯性心電閘控掃描技術能給予病人較低的幅射劑量，且維持良好之影像品質。

關鍵字

多排偵檢器電腦斷層掃描儀 ； 小兒 ； 心臟電腦斷層 ； 輻射劑量 ； 影像品質

並列摘要

Multiple detector computed tomography (MDCT) has been widely used in assessment of CT coronary angiography (CTCA) for adult population. However, it is still a challenge to perform cardiac CT for pediatric population. It is higher heart rates and smaller cardiovascular structures in children, therefore, an advanced 64-slice or 256-slice CT is indeed in favor of acquiring cardiac images delicately. Until now, related researches have yet to find complete details about coronary angiography studies on 256-slice CT in pediatrics. Therefore, this study aimed to evaluate the image quality and radiation doses between 256-slice CT and 64-slice CT for pediatric population. A series of CTCA protocols including prospective gated axial (PGA) protocol, retrospective gated helical (RGH) protocol and non-gating scanning protocol were used. We separately performed 64-slice and 256-slice CT in the setting for 1-year-old and 5-year-old children. Furthermore, to evaluate the image quality, an American College of Radiology (ACR) phantom was used. Results showed that the PGA protocol had a lower radiation dose than RGH protocol did in the setting of gated CTCA protocol. Also, PGA protocol maintained good image quality, though it was unable to record the entire cardiac cycle. Moreover, non-gating scanning protocol could reach low-dose diagnostic purposes, which trade-off was incapable to synchronize a cardiac cycle, due to the let fall of time resolution. Overall, this study showed that the PGA protocol on 256-slice CT was the preferable choice in balancing radiation exposure and image quality in cardiac CT for pediatrics.

並列關鍵字

multi-slice CT ； child ； cardiac CT ； radiation dose ； image quality