心房運動功能評估之工具發展

Method of Estimating the Atrial Function and Wall Motion

翁正軒(Cheng-Hsuan Weng)

指導教授 ： 胡威志

中原大學/工學院/生物醫學工程學系/碩士(2008年)

https://doi.org/10.6840/CYCU.2008.00031

摘要

心房纖維性顫動起因於竇房結產生的動作電位在心房肌肉上混亂傳導，部分活化心肌的電流反覆地再興奮原來的區域，持續地循環刺激導致心房某些部位的收縮步調無法一致而降低其輸血功能。電腦斷層掃描可以記錄心臟搏動過程的瞬間影像並以數位化儲存，藉由觀察多時序影像之間的左心房收放型態變化可以應用於分析異常節律性心房腔室壁之運動。
計算心房壁運動首先要克服不同時序影像中相同參考依據座標校正的問題，在型態變化的分析領域裡，圖形配準常被作為完成影像之間特徵參考圖形匹配之方法，本研究利用高品質的心臟電腦斷層影像，有效率地計算影像之間的匹配程度，排除造影過程中非左心房運動的干擾。在心房的輪廓圈選是使用區域成長演算法，利用這些輪廓的資料計算房壁運動來評估左心房在各區域的舒張及收縮功能。
透過本研究開發之系統工具分析二十組的心臟電腦斷層影像（11個正常人，9個心房纖維性顫動患者），結果顯示，正常人與患有心房纖維性顫動的病患，位於左心房的左下方前、後側靠近僧帽瓣處有顯著差異：正常人的前、後側平均移動量各為6.37±1.81mm及7.01±1.72mm；AF患者的前、後側平均移動量各為8.76±1.46mm及9.20±1.63mm，p value<0.01。此外，以向量分析環繞右下肺靜脈周圍的心房壁下、後區塊亦有顯著差異：正常人的下、後區域向量大小變化分別為0.045±0.016及0.051±0.022；AF患者的下、後區域向量大小變化各為0.089±0.038及0.085±0.028，p value<0.01。代表著患有心房纖維性顫動的病患會導致左心房局部功能異常，在臨床診斷與治療上便可藉由型態的改變作為判斷的指標。

關鍵字

圖形配準 ； 房壁運動 ； 心房纖維性顫動 ； 左心房 ； 區域成長

並列摘要

Atrial fibrillation is caused by the disorderly action voltage which generates by sinoatrial node in the atrium. Some of the excited cardiac muscle patterns are re-stimulated by the recurrent impulse which makes the left atrium contract irregularly. As the heartbeat goes by, these cardiac patterns change can be taken down immediately by the CT scan. With the various time of CT images, we can analyze the abnormal rhythmic wall motion of heart chamber.
For calculation of wall motion, reference which being a fixed figure in different time of CT image series must be calibrated slice by slice. In the analytic field of pattern changes, image registration is often taken as the method to complete characteristic reference matches between images. This study utilizes the high-quality cardiac CT images to efficiently calculate the matching degree between the CT images so that we can rule out the interference occasioned by the non-left atrium motion during the CT scan. As to delineate the atrial profile, we adopt seed region growth algorithm. By means of the profile data, we can analyze the atrial wall motion to evaluate the contraction extent of all regions in the left atrium.
With the system built by this research, analysis of the 20 cardiac CT images (eleven being normal and nine suffering from atrial fibrillation) indicates the obvious differences between the normal people and the patients at issue. For the normal ones, the average side motion at anterior and posterior of left inferior wall readings are 6.37±1.81mm and 7.01±1.72mm; for the patients, the readings are 8.76±1.46mm and 9.20±1.63mm，p value<0.01. Besides, there is another difference with regard to the vector analysis of LA areas circling the right inferior pulmonary vein. For the normal, the magnitude of difference at inferior and posterior patterns readings are 0.045±0.016 and 0.051±0.022; and for the patients, the readings are 0.089±0.038 and 0.085±0.028，p value<0.01. These analyses implicate that the AF patients would develop partial malfunction in the left atrium. Therefore, they will serve as the diagnose index when clinic diagnoses and treatments are in process.

並列關鍵字

Seed Region Growth ； Image Registration ； Wall Motion ； Left Atrium ； Atrial Fibrillation

參考文獻

﹝10﹞ Stephen M. Pizer, P. Thomas Fletcher, Sarang Joshi, Andrew Thall, James Z. Chen, Yonatan Fridman, Daniel S. Fritsch, and A. Graham Gash, “Deformable M-Reps for 3D Medical Image Segmentation,” International Journal of Computer Vision, vol. 55, pp. 85-106, 2003.

﹝12﹞ Hideki Yamamoto, Tetsuya Sano, Tsuneharu Morito and Yoshio Hiraki, “Image Analysis of Left Ventricle Wall Motion by MRI Tagging,” Technology and Applications, International Workshop, pp. 91-94, 2001.

﹝22﹞ 陳巨弦, “實時四維超音波動態心臟影像顯示及分析系統,” 中壢中原大學, 2005.

﹝23﹞ 吳明鴻, “利用心臟電腦斷層影像評估左心房與左心耳之射血功能,” 中壢中原大學, 2007.

﹝1﹞ Zhaohui Zhang and Veronique Prinet, “A Rough–to–fine Satellite Image Registration Method with Sub-pixel Accuracy,” IEEE International Conference on Image Processing, vol. 3, pp. 385-388, 2002.