建構複數心結構動態模擬工具評估分析左心房左心室之運動功能

Construction of multi heart structure four-dimensional dynamic simulation tool for assessment of left ventricular and left atrium motion function

楊少康(SHAO-KANGF YANG)

指導教授 ： 胡威志

中原大學/工學院/生物醫學工程研究所/碩士(2013年)

https://doi.org/10.6840/CYCU.2013.00324

摘要

本研究旨於建構一套心臟醫學影像分割工具，做為進行心臟功能性分析的輔助工具，程式具備以下特點：
　　一.能實現心臟腔室心內膜與心外膜的分割。分割處理分為兩個部份，先使用區域成長法長(seeded region grow)取得心內膜資訊，並將心內膜的形狀進行倍率放大，並將放大區域作為限制範圍，將區域成長的目標從腔室改為肌肉，在限制的範圍內進行第二次的區域成長，即可取得心外膜資訊。之後可分別計算腔體以及腔槽體積，兩者相減後可獲得心臟心肌層的體積資訊。
　　二.能將左心房左心室兩個腔室的運動資訊整合顯示，可以更加全面的評估心臟的整體功能。
　　三.透過影像處理，能將腔室肌肉纖維對腔室邊緣的影響消除。處理的方法同樣利用事先取得的心內膜資訊，在心內膜內進行封閉區域填滿，藉此消除周邊肌肉產生的不規則曲線。此舉可提升四維動態分析的品質，也利於進行腔室心外膜之分析。
　　透過本系統，使用者可以透過心臟電腦斷層影像(computed tomography,CT)得到：腔室容積、腔室周圍心肌體積以及腔室在不同時序下的三維幾何形狀，以利後續的研究與分析。本研究對三位心房顫動病患進行資料的擷取後，發現左心房心肌層於心動週期中體積的變化不明顯的趨勢（連續的時序的體積變動平均為1.494 ± 0.379 cm3。最大體積與最小體積的差値為5.094 ± 1.631 cm3。），透過視覺判讀的方式對所擷取的影像進行驗證動作，條列出腔體於各時序下之立體模型，標示心內膜與心外膜之區域，並觀察分割結果是否符合數據資料的特徵趨勢，其結果表明本研究所使用之分割方法具備穩定的準確性。

關鍵字

心臟斷層影像 ； 區域成長 ； 腔室心內膜心外膜分割

並列摘要

The aim of this study is to build a software tool for cardiac analysis using noninvasive 4D CT cardio-images. The tool will be used for anatomic heart chamber structure segmentation and quantization of cardiac function. This System has three new features added to previous studies. Firstly, through image processing, the tool could remove motion artifact from the shadow image caused by the motion of chordate tendineae and papillary muscle in the ventricle. It could be smoothing the contour of border through area extrapolation methodology and will be reconstructing a good visualization of cardiac model.

Secondly, it can segment both endocardial and epicardial border in two processes. One could identify the endocardial contour of cavity with seeded region growth. And, the other, one could make the endocardial contour as an introduction contour to delineate epicardial contour. After all part of delineation had been accomplished, the contour of epicardial and endocardial could be described and the volume of chamber or the volume of cavity was calculated. Therefore, the volume of myocardium could be calculated by ventricular cavity’s volume subtracted from whole epicardial volume.

Thirdly, the developed tool can display the motion of left atria and left ventricle simultaneously. In the display window endocardial border will been evinced red model and epicardial order will been evinced green. Simulated left ventricle will been evinced green yellow model. User can overlap those models for details observation. The display window could also show Bull's-eye diagram in synchronous with the beating heart model. It could help understand the wall motion of heart chamber. Thus, the global function of heart could be illustrated and comprehended more easily.

With this analysis system, user can measure several functional parameters from the reconstructed heart model using computed tomography images. The parameters that could be used at post analysis included volume of chamber cavity, volume of chamber myocardium and chamber's 3D model in different time sequence. In this study, we have measured functional parameters in three patients with atrial fibrillation. The results showed that the volume change of left atrial myocardium within the cardiac cycle is very tiny. From our evaluation of C.T. Time series data, the average value of each variation is only 1.494 ± 0.379 cm3 and whole cycle change (max. - min.) is only in 5.094 ± 1.631 cm3. We also confirmed this by only from visual image view. this demonstrated that the segmentation processes in the developed tool was credible.

並列關鍵字

computed tomography image ； region grow ； segment endocardial and epicardial

參考文獻

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