半自動式左心室三維動態模型之運動和形態分析系統

Wall Motion and Shape Analysis System of 3D LV Dynamic Modal with Semi-Automatic Border Delineation

李佳融(Chia-Jung Lee)

指導教授 ： 胡威志

中原大學/工學院/醫學工程研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200587

摘要

本研究提出一個超音波心臟影像左心室改進的邊緣搜尋演算法，採用動態邊緣圈選(Active Contour)進行原始影像圓柱平面掃瞄(Polarized Scan)，初步建立邊緣控制點，將控制點由圓柱座標轉為立體空間座標後，配合第二次動態邊緣圈選(Active Contour)，做Z平面掃瞄（Z-Cube Scan），可快速且正確的搜尋食道超音波影像左心室腔室邊緣，以此邊緣資訊運算左心室容積及左心室功能性參數，顯示心臟功能是否正常。因食道超音波影像為多角度，多時序影像，所以本研究採用，手動圈選幾個不同角度左心室影像初始邊緣，配合此演算法使用。
驗証此邊緣搜尋演算法是否正確時，採用容積驗証方式，以水球容積本系統所得之容積相比較。結果圓柱平面掃瞄(Polarized Scan)配合Z平面掃瞄（Z-Cube Scan）技術所得容積結果會較只以傳統動態邊緣圈選（Active Contour）技術精確，其相關係數為0.9685。臨床容積驗証上，尤於左心室容積沒有標準可做為比較，所以採用與醫院所使用的容積量測系統相比，容積結果均呈現正相關，相關係數為0.9364，肉眼觀察此技術搜尋之左心室邊緣均貼附於影像邊緣。此技術加上高度半自動化的初始邊緣搜尋，較同種類的左心室分析系統快速。
利用正確邊緣搜尋及高速的優點，本研究可提供左心室容積參數量測及形態分析和心室壁運動參數分析，為方便觀察，採用牛眼圖(Bull’s Eye)的方式，以顏色呈現左心室功能性參數結果，將牛眼圖(Bull’s Eye)結果貼附於左心室立體模型上，顯示左心室心摶週期中運動異常的部位，高度視覺化的觀察左心室模型及功能性參數指標。

關鍵字

3D+1D ； 超音波 ； 容積量測 ； 心室壁運動分析 ； 形態分析 ； 動態圈選 ； 左心室

並列摘要

This paper reports an improved methodology of LV contour delineating procedure of Transesophageal Echocardiography (TEE) image of heart. The active contour algorithm was used to delineate LV chamber from initial images in Cylinder coordinates (Polarized Scan). The LV chamber was delineated again (Z-Cube Scan), using previous delineated information in Cartesian coordinates. Using this, the Left Ventricular of TEE image can be traced more efficiently and correctly. From the delineating contour of LV, the LV volume can be calculated by Simpson’s rule. The ejection fraction (EF) can be calculated from the volume at end diastolic volume (EDV) and end systolic volume ESV. The above procedure was initiated using a set of hand-traced pattern to improve the efficiency of delineation process. The procedure was proved effectively and accurately.
This paper uses volume validation to prove the effectiveness of methodology for delineating border. The volume calculated from the images was compared to the volume of water balloon. The result shows the volume calculated by this methodology of using Polarized Scan and Z-Cube Scan is more accuracy than the preciously reported studies. The coefficient of correlation is 0.9685. Because the volume of LV does not have the gold standard, the LV calculated volume was tested to the volume calculated by Tomtec heart analysis system. The result shows positive correlation. The coefficient of correlation is 0.9364.
With the excellence of LV border delineating, this paper also reported the capability of calculating LV volume, parameters of LV shape analysis and wall motion analysis. The Bull’s Eye display method was used to illustrate the results of shape analysis and wall motion analysis. Texturing the LV 3D model by this Bull’s Eye Image, this system can display the unusual repositions of LV border in heartbeat.

並列關鍵字

Left Ventricular ； supersonic ； shape analysis ； active contour ； volumn calculation ； LV wall motion analysis ； 3D+1D

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