建構左心室四維動態模擬工具評估左心室心肌運動功能

Construction of four-dimensional dynamic simulation tool for assessment of left ventricular myocardial function

馬銘徽(Ming-Huei Ma)

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(2010年)

https://doi.org/10.6840/cycu201000862

摘要

心血管疾病的病患通常會伴隨著心臟運動異常的病徵，雖然藉由多時序的電腦斷層影像系統可以快速且安全的獲得心臟運動的狀況，但是卻無法提供醫生足夠的局部心肌的運動資訊，因此本研究利用電腦斷層影像建構動態的模擬工具以評估整體性左心室功能與局部心肌的運動功能。
本研究首先建立左心室的立體模型並且校正中心軸，其中心軸為二尖瓣到心尖的連線，經手動校正後做重新取樣獲得以左心室長軸為中心的左心室短軸影像，然而為了精確計算每一塊心肌的運動，利用旋轉公式調整心肌位置，並且計算左心室長軸變化與半徑變化率這兩項模擬參數。在模擬方面本研究將左心室運動分解成兩種動作，其一為長軸變化的運動，其二為半徑變化率與阿基米德螺旋的扭轉運動。將左心室心肌分割18區塊以動態影像與牛眼圖顯示運動變化計算局部射血分率與心肌位移變化以分析左心室局部心肌功能。
實驗部分以十三位受測者的實際與模擬的左心室功能作分析，數據分析分為兩方面，其一為整體性左心室功能分析，利用左心室容積曲線與左心室容積變化率曲線證明實際與模擬左心室的整體運動狀況的相似度，而左心室容積(r=0.99)與左心室容積變化率(r=0.97)的結果顯示出很高的相關度。其二維局部心肌運動分析，根據實際與模擬的局部射血分率與心肌位移變化做相關性與差異度分析，結果顯示其差異度在±2SD之內，而心肌位移變化相關性為(r=0.87)呈現出很好的相似度，藉由實驗結果說明本研究就建構的模擬工具對於模擬左心室運動的可行性。

關鍵字

局部射血分率 ； 阿基米德螺旋 ； 半徑變化率

並列摘要

Patients with cardiovascular disease such as cardiomyopathy and myocardial infarction were usually having abnormal myocardial motion.
The cardiac contraction and relaxation information could be obtained speedily and safely by multiple slices CT imaging system with multiple phases. However, Four Dimension non-invasive cardiac medical images could not provide enough information of regional myocardial motion for physicians. Thus, to assess left ventricular function (LV) and regional myocardial motion, a dynamical simulating tool was constructed in this research.
The 3D LV model was constructed from 4D MSCT images. For data pre-processing in this study, firstly, the reposition of the left ventricle in short axis view, the central axis of the 3D LV model was adjusted manually to be aligned with axis that was constructed using central point of short axis LV image from mitral valve to the apex of left ventricle. And, then, the short axis LV images were obtained by re-sampling.
Each unit of myocardial motion was calibrated by assuming a rotating function based on volume time curve of LV ejection function to the unit. Thus, the LV motion could be simulated by shortening of long axis and the twist of myocardium using the rate of radius of change by Archimedan Spiral function.
To illustrate the regional myocardial motion, the data was portraying with the common accepted 18 myocardial regions on a Bull eyes graphical figure with the lively video display. A high resolution of 900 segments illustration was also provided.
The result showed that correlation between simulated and controlled volume-time curve (VTC) was highly correlated. The VTC was 0.99 (r=0.99) and rate of volume change (RVC) was 0.97 (r=0.97). This demonstrated that the high correlation of global LV motion between the controlled data and 3D LV motion model.
For the regional LV motion, the correlation between simulated model and controlled motion data of 18 myocardial regions on a completed cardiac cycle was 0.87(r=0.87). The Bland-Altman analyses on the regional myocardial motion and regional ejection fraction were both within ±2STD. This demonstrated that the simulated model and the controlled data at every LV myocardial motion of whole cardiac cycle were similar.
These results showed that a designated set of contraction functions was able to simulate the LV contraction that will be producing desired cardio output.

並列關鍵字

the rate of radius of change ； regional ejection fraction ； Archimedan Spiral

參考文獻

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