提昇冠狀動脈多列式電腦斷層之影像品質：閉氣後延遲掃描技術的運用

Improvement in Coronary Angiography Image Quality using Multi- Detector Computed Tomography: Use of Delayed Scanning after Breath-hold

罹患嚴重冠狀動脈粥狀硬化的致死率相當高，唯有早期的診斷與適時治療可以有效降低致死率。以往都是利用心導管血管攝影及侵入性血管超音波來做為主要檢查方法，但皆屬於侵入性檢查，現今可以利用非侵入性的多列式電腦斷層來進行檢查及診斷。由於冠狀動脈多列式電腦斷層攝影是利用回朔式心電圖同步影像擷取技術進行影像重組，所以心跳頻率在影像品質具有關鍵性的影響。本研究針對30位健康檢查病患，並且利用呼吸控制來觀察閉氣後心跳頻率變化，發現第三秒之後心跳頻率較前兩秒降低了10.1個百分比，由於運用回朔式心電圖同步影像擷取技術來重組影像，此心跳頻率變化會降低影像品質。藉由閉氣後延遲些許時間後再進行掃描，將可以有效減少心跳頻率落差，並且掃描期間能在較低且規律的心跳頻率下進行檢查。因此利用閉氣後延遲技術於心臟冠狀動脈多列式電腦斷層攝影檢查，可以有效率提昇整體影像品質。

Early diagnosis and treatment of coronary atherosclerosis is essential in reducing the mortality rate from this disease. Conventional catheterization angiography is the diagnostic standard for determining the presence, location and severity of coronary artery disease. Multi-detector computed tomography (MDCT) angiography is a noninvasive alternative to cardiac catheterization which uses retrospective ECG gating to reconstruct images of the coronary arteries. The key factor in the acquisition of quality images involves control of the heart rate. Using breath control techniques, we observed that the heart rate after breath-hold in 30 patients is reduced by 10.1% between the first two seconds of breath-hold and the third second. This reduction in heart rate degrades the quality of images that are reconstructed by retrospective ECG gating during MDCT. Therefore, delaying the scan after breath-hold may effectively avoid the drop in heart rate and provide scanning within a more regular heart rate period. Delayed scanning after breath-hold during coronary angiography using MDCT can, thus, potentially improve image quality.