利用實時四維心臟超音波影像評估左心室功能

Analysis LV function with Real-time 4D Echocardiography

郭紀翔(Chi-Hsiang Kuo)

指導教授 ： 胡威志

中原大學/工學院/醫學工程研究所/碩士(2007年)

https://doi.org/10.6840/CYCU.2007.00647

摘要

在心臟疾病的診斷與治療上左心室的收縮與舒張的功能性測定是很重要的。室壁收縮與放鬆的功能可能可以從心動週期心室容積的變化中得之，利用四維心臟超音波影像，許多參數可以從心臟的容積時間曲線研究中取得，這些參數包括射血比率、最大排血率和最大充血率，而最大排血率到最大充血率的變化率可以表現出收縮與舒張狀態的功能。
在一個心臟週期，四維心臟超音波影像需要18到22個心臟影像的序列，每一個心臟影像序列可以從心內膜的輪廓計算出一個左心室容積。利用容積時間曲線可以簡易的找到舒張末期容積、收縮末期容積以及射血比率，而從容積時間曲線的一次微分計算可以得知最大排血率與最大充血率。在心內膜與心外膜的輪廓是使用動態邊緣模組，利用這些輪廓的資料，可以計算出室壁運動百分率以及室壁厚度百分率。
分析五個正常人的實時心臟超音波影像，其平均射血比率為54.75±6.71%，射血比率可以表示這些對象的左心室功能皆為正常，而在結果中顯示出最大排血率到最大充血率的變化率大者其射血比率也相對的較好(r=0.97)，也顯示出射血比率與室壁運動百分率和室壁厚度百分率參數也有很高度的相關性，相關度分別為-0.95與0.95。代表著左心室腔室在收縮期間所作用的力量較大，而從心室打出去的血液也會相對的多，腔室在運動時與心肌力在收縮時的功能性越強其射血比率會因此變的越高。

關鍵字

左心室 ； 室壁厚度 ； 動態邊緣模組 ； 室壁運動 ； 心臟超音波

並列摘要

Determination of diastolic and systolic left ventricular function is important in diagnosis, therapy, and follows up studies of cardiac diseases. The contraction and relaxation functions could be accessed with the change ventricular volume during the cardiac cycle. Many parameters were extracted from volume-time curve (VTC) using 4D echocardiography image that could be used in cardiac study. The parameters were ejection fraction (EF), peak ejection rate (PER) and peak filling rate (PFR) of the ventricle. For example, the rate change from PER to PFR could be representing the function of systole and diastole state.
In one heart cycle, 4D echo images data set may include 18-22 frames of cardiac image volume. For each cardiac image volume frame, one LV volume can be calculated from the delineated endocardial contour and the LV chamber volume and myocardial volume can be totaled from area of each image slice using Simpson rule. Using VTC, one may easily found EDV, ESV and EF. The PER, PFR can be calculated from the first derivative of VTC. The tracing of endocardium and epicardium were using active contour model (ACM) with cubic spline. Using these contour data, the percent of wall motion and percent of wall thickening were calculated and tabulated along with the volume information.
Five sets of 4D live echocardiograph were analyzed using self-developed cardiac image analysis program, the mean LVEF was 54.75±6.71%. These ejection fractions indicated that the left ventricle function of these subjects were normal. The result showed that the correlation between EF and the rate change from PER to PFR was 0.97 (r=0.97). The EF and the percent of wall motion was 0.95 (r=-0.95). And, the EF and the percent of wall thickening was 0.95 (r=0.95). In examining the EF with rate of change from PER to PFR in cardiac cycle, the ventricle having a better EF will be having a sharper slope of the volume change. And, the ventricle having a better EF will be having a larger chamber motion and myocardial contraction.

並列關鍵字

wall thickening ； echocardiography image ； active contour model ； left ventricle ； wall motion

參考文獻

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