4D左心室心肌運動變量模型之應用

Four-dimensional Wall Motion Model for Application of Left Ventricular Myocardial Function

簡士凱(Shi-Kai Chen)

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(2017年)

https://doi.org/10.6840/cycu201700191

摘要

心室重塑與整體心肌的受力分配不均有著顯著的關係，文獻指出心室重塑是連續一段時間下心肌功能結構的改變，因此若能找出運動不良的區域，對於心室重塑的預防與監測上能提供另一種參考資訊，本研究利用電腦斷層影像建構四維心肌運動模擬工具，評估左心室各區域心肌的運動功能。
心肌運動功能檢測工具使用區域成長法找尋訂定心內膜與心外膜邊界，手動校正中心軸獲得以左心室長軸為中心的左心室影像，以內外膜資訊計算向量獲得心肌變化量值，再利用心內膜與外膜資訊建構一個時序可建1800格的三角立體網格模型，根據十個或更多時序之立體模型上心肌變化量分析不同區塊的心肌變化量的程度不同在左心室立體模型上以紅、黃、綠、淺藍與深藍等顏色呈現區塊動量，其中深藍色區塊為區域心肌運動量與平均心肌運動量相比低於2mm以下的區域，低運動量區域之心肌為運動不良的心肌肌群，系統記錄發生的位置與計算低運動量區域的範圍面積及計算相關參數。
本研究發現患者手術後部位，約有40%不會產生纖維化組織，但心肌損傷較嚴重時，即使無纖維化組織產生，仍然會表現出低運動量狀態；當患者具有纖維化區域(60%)，此區必定會發生低運動量狀態，且低運動量區域位置與纖維化區域位置必定重疊；此外本研究也觀察到心肌運動量下降會導致低運動量區的半徑變化率比健康區域來的低；結果表明本研究的模擬工具能夠有效評估心肌功能狀態與纖維化區域位置，對於評量左心室運動有可行性。

關鍵字

左心室重塑 ； 心肌運動 ； 纖維化組織

並列摘要

The synergy of myocardial contraction creates an effective cardiovascular pumping system. Regional dysfunction of myocardium will be leading to functional abnormality of cardiac wall motion that is one of the risk factors for ventricular remodeling and heart failure. Early detecting abnormality of wall motion and treated could prevent further deterioration. This study sought to characterize global and regional systolic function abnormalities.
The self-developed 4D image processing software will be extracting the wall motion of left ventricle from a 4D cardiac images. A seeded region growing incorporated active contour method was designed to locate the edge of endocardial and epicardium. A 3D harmonic phase method using 3D triangle mesh was utilized to construct a 3D grid model of heart. Myocardial wall motion value in different extent will be marked with colors in 3D model. With 10 frames of 3D heart model and the shortening of ventricular long axis, the left ventricular wall motion could be predicted. The region of wall motion with less than 2mm that was lower than average will be marked with dark blue color for illustration. The coordinates of lower motion areas and related LV parameters were characterized and recorded. Four data set of fibrotic scar delay enhanced cardiac images and 4D cardiac wall motion images was used to test this non-invasive method of early detection cardiac abnormality. The patient after surgery with fibrotic scar tissue necessarily has lower myocardial motion value. However, fibrotic scar tissue will not show up in 40% of patients after surgery but the operated area may still have lower myocardial motion.
The detection wall motion could effectively reflect the dysfunction of myocardium. Thus, this study provides a new approach to assess the degree and site dysfunction area of myocardium.

並列關鍵字

Left ventricular remodeling ； Myocardial wall motion ； Fibrotic tissue

參考文獻

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