利用肺動脈脈波傳導速率評估右心室順應性與肺動脈順應性之間的相關性

動脈硬化已經被證實是許多心血管疾病(CVD)的重要危險因素之一，為了能夠精確的評估血管硬化程度，以非侵入式的方式量測動脈順應性(AC)和脈波傳導速率(PWV)是現今醫學上最常用來分析人體血管特性的方法。本研究目的是利用肺動脈脈波傳導速率(PA-PWV)評估右心室順應性及肺動脈順應性之間的相關性，利用本研究室自行開發的醫學影像處理系統，使用以DICOM(Digital Imaging and Communications in Medicine)為儲存格式的電腦斷層掃描影像(CT)，針對肺動脈部位做觀察與分析。我們分析15位受測者的左、右心室心輸出量容積參數與計算射血分率，來驗證本開發系統的準確性與可行性，結果顯示左、右心室容積的相關性為R2=0.6457，p<0.0001，經過計算之後左心室射血分率為57~78%，平均為66±6%；右心室射血分率為42~65%，平均為52±6%，其所有的變異係數與正常人的數值相比皆在10%以下。評估肺動脈脈波傳導速率參數部分，使用三維的影像技術，將影像重新取樣成以肺動脈為新的中心軸後，進行邊緣圈選的容積計算，取得各時序下肺動脈的容積與時間參數後，使用了兩種不同計算肺動脈脈波傳導速率的方法，結果顯示較為優異的方法是利用最大、最小斜率的方式，來定義計算脈波傳導速率所需的相對距離(ΔD)，得出平均肺動脈脈搏傳導速度為0.15±0.05(m/s)並將結果繪製成VTC曲線圖。在計算順應性的部分，壓力變化量是藉由都卜勒心臟超音波來獲得受測者的肺動脈收縮壓(RVSP)，而容積變化量則是使用我們的軟體來計算右心室和肺動脈的容積，計算出右心室順應性平均為2.59 ± 0.84 (mL/mmHg)、肺動脈順應性平均為0.08±0.04(mL/mmHg)。接著利用肺動脈脈波傳導速率來評估右心室順應性(R2=0.585，P<0.001)和肺動脈順應性(R2=0.716，P<0.001)的相關性皆呈現良好的負相關趨勢。此外，我們還針對同一觀察者和不同觀察之間，做肺動脈順應性和脈波傳導速率的變異係數及相關係數分析。結果顯示在同一觀察者內的變異係數與相關係數分別為14.29%、13.12%，R2 = 0.92、R2 = 0.69，而在不同觀察者之間的數值分別為11.21%、11.59%，R2 = 0.87、R2 =0.72，具有良好的相關性和變異性。综合上述的結果証實，本研究使用了自行開發的影像處理系統，成功的利用醫學影像計算出肺動脈脈搏傳導速度，提出了在右心室順應性和肺動脈順應性之間具有一個良好的正相關性存在(R2=0.625,p<0.001)。

關鍵字

三維心臟電腦斷層影像；動態邊緣；右心室順應性；肺動脈順應性；肺動脈脈波傳導速率；區域成長

並列摘要

Arterial stiffness has proven to be one of the most dangerous factors of many cardiovascular diseases (CVD). Recent studies have shown that Arterial Compliance (AC) and Pulse Wave Velocity (PWV) are the common medical method to measure the stiffness of arterial vessels. The purpose of this study is to understand the correlation between Right Ventricle Compliance (CRV) and Pulmonary Artery Compliance (CPA) by using Pulmonary Artery Pulse Wave Velocity (PA-PWV). By using the self-developed image processing program, we try to observe and analyze the change of the pulmonary artery through the cardiac DICOM image of 3D heart model. We analyze and compare 15 subjects’ Cardiac Output (CO) volume parameters and Ejection Fraction (EF) of Left and Right ventricular to ensure the accuracy and feasibility of this research. The results showed that the relationship between the cardiac output of the left and right ventricular was R2=0.6457, p<0.0001. The ejection fraction of left ventricular was 57-78% (mean was 66 ± 6%) and the right ventricular was 42-65% (mean was 52 ± 6%). Compared with the normal value, all of the coefficients of variation were less than 10%. As for the evaluation of PA-PWV, we use the 3D image technique and set the original pulmonary artery value as short axis, and the re-extracted value of the 3D heart model through a semi-automatic way as the centerline. During the re-sampling period, the user has to specify the start and end value of the pulmonary artery to get correct position and image. Then we use two methods to compare the pulmonary artery pulse wave velocity of the volume value and time from the pulmonary artery in different time course, the result showed that the more excellent way is to use the maximum and minimum slope to define the relative distance (ΔD) of the pulse wave velocity. And we found that the average pulmonary artery pulse wave velocity was 0.15 ± 0.05 (m/s). And the result will be drawn into the VTC line diagram. As for the compliance, we use the Doppler echocardiography to get the RVSP of pressure change and use our image processing program to get the volume change of right ventricle and pulmonary artery. By calculate the ratio of the RVSP and volume change, we get that the average compliance of right ventricle was 2.59 ± 0.84 (mL/mmHg) and the average compliance of pulmonary artery was 0.08±0.04 (mL/mmHg). Then we use PA-PWV to compare the compliance of right ventricle(R2=0.585，P<0.001) and pulmonary artery(R2=0.716，P<0.001), and found that both of correlation with PA-PWV were negative. Besides, we compare and analyze the coefficient of variation and correlation coefficient of the compliance of pulmonary artery and PA-PWV form the intra- and inter-observer. We found that the coefficient of variation and correlation coefficients in the intra-observer were 14.29%、13.12%, R2= 0.92、R2= 0.69, and the inter-observer were 11.21%、11.59%, R2= 0.87、R2=0.72. Both of the coefficients of variation and correlation coefficient were positive. As above, we use our image processing program to calculate the PA-PWV successfully, and prove that the correlation of the compliance between right ventricle and pulmonary artery was positive (R2=0.625, p<0.001).

並列關鍵字

active contour ； right ventricle compliance ； pulmonary artery compliance ； pulmonary artery pulse wave velocity ； seeded region grow ； 3D cardiac computed tomography

參考文獻

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[15] 李佳融，“半自動式左心室三維動態模型之運動和形態分析系統”，中原大學醫學工程所，碩士學位， 2002。

[3] 陳奕瑋，“利用電腦斷層掃描評估動脈脈波傳導速度”，中原大學醫學工程所，碩士學位， 2011。

[14] Hideki Yamamoto, Tetsuya Sano, Tsuneharu Morito and Yoshio Hiraki（2001）： “Image Analysis of Left Ventricle Wall Motion by MRI Tagging” Technology and applications, international workshop, on page 91-94

[1] Babin D, Devos D, Pizurica A, Westenberg J, Vansteenkiste E, Philips .”Robust segmentation methods with application to aortic pulse wave velocity calculation Computerized Medical Imaging and Graphics” W2013 38 179-189

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利用肺動脈脈波傳導速率評估右心室順應性與肺動脈順應性之間的相關性

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