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  • 學位論文

利用心臟電腦斷層影像評估左心房與左心耳之射血功能

Estimate the Ejection Fraction of the Left Atrium and the Left Atrial Appendage from Medical Cardiac CT Image

指導教授 : 胡威志

摘要


許多心臟疾病會導致心臟房室的容積異常,心房纖維性顫動(atrial fibrillation, AF)是因為竇房結(sinoatrial node, SA node)不規則的電位傳遞使左心房(left atrium, LA)無法有效收縮,其容積收縮變化,即射血功能(ejection fraction, EF)較正常人還要小。本研究所採用電腦斷層(computed tomography, CT)掃描的心臟影像,針對左心房、左心耳(left atrial appendage, LAA)和肺靜脈(pulmonary vein, PV)的容積、截面積、射血功能參數開發一個電腦分析系統進行觀察與討論,並提供三維的心臟影像系統,可以多角度、多方位與多切面觀察心臟的整理生理架構,搭配已搜尋的邊緣資訊可以針對左心房、左心耳進行觀察。 本研究以手動與自動方式將左心房與左心耳、左心室、肺靜脈相連的部分產生區分的界線,左心耳和左心室是以手動方式將其與左心房區分;肺靜脈是從三維立體影像裡找出肺靜脈切平面並建立區分界線。左心房與左心耳的邊緣搜尋,本研究分別使用動態邊緣(active contour: snake)與區域成長(seeded region grow)兩種方法進行邊緣搜尋,並進行容積的運算與其結果分析。 本研究利用兩個假體測試的容積校正,兩次測試的結果準確率分別為96.06%與96.92%,分析30個病人的影像實驗,分析肺靜脈截面積大小,結果呈現四條肺靜脈裡的兩條上側截面積明顯大於下側的兩條,p<0.05。肺靜脈截面積在不同時序的變化並無規律性地變小或變大,主因在於左心房的外在收縮或舒張應力影響了肺靜脈的應力,此稱為伸展效應(stretch effect)。此外、將病人分成左心房容積大於100ml (Group I)與小於100ml (Group II)兩組,分析左心房容積與射血功能結果顯示,Group I的左心房射血功能低於20%比例達41.18%,Group II左心房射血功能低於20%比例為7.69%,結果呈現左心房容積較大時,容易使其射血功能降低;反之容積較小,其射血功能較高且較穩定。以心房纖維性病患和非心房纖維性病患重新分組,分析他們的左心房和左心耳射血功能,結果呈現患有心房纖維性顫動病患的左心房射血功能比較低,p=0.03475,左心耳的射血功能以平均值觀察亦比較低,p=0.16491。最後本研究將所有病人資訊執行兩種邊緣搜尋的機制,結果呈現兩種方法相關度r-square value=0.9893,彼此有著高度相關。

並列摘要


Atrial fibrillation will lead to abnormality of atrial ejection function. The radio ablation or medication that will be blocking the unwanted electrical pathway on the atrium will be the choices of medical therapies. Therefore, to assess the outcome of treatment non-invasively is the importance issue to determine the successful of these medical therapies such as atrial ablation. The function of left atrium can be accurately estimated non-invasively using 4D CT cardiac images and a good analysis tool. In this research, a self-developed 4D Cardiac CT images analysis program was reported. The procedure of the program will be reconstructing the 3D volume of heart first. Then, a cut plane method is utilized to accurately delineate the 4 pulmonary veins and set the boundary at mitral valve for the left atrial contour extraction. The delineated information can be mapped onto the original CT images. With this prior processed information, the active contouring methodology and seed region growth methodology were implemented in the program for 3D atrial segmentation. The contour information will be re-sampled for the reconstruction of wire-mesh display. Then, the atrial volume and the dimension of pulmonary veins can be accurately assessed. The methods of active contouring and seeded area growth for volume calculation were able to estimate volume within 5% of error using 500 ml saline with contrast medium in bag. In result and the application, a set of thirty 4D CT cardiac images were acquired at 30% and 90% of RR interval. The left atrial volume was evaluated and the Ejection Fraction (EF) was calculated. The statistic for the dimension of the pulmonary veins shows that the two superior veins are larger than the two inferior veins (LSPV: 2.76 ± 1.33mm2, RSPV: 2.58 ± 1.21mm2, LIPV:1.74 ± 1.14mm2, RIPV: 1.97 ± 0.84mm2, p < 0.05). This result is paralleling to the previous finding. The result also shows that patient with AF, the ejection function is much lower than the control group (Exp: 30.81 ± 13.61%, Ctrl: 36.69 ± 19.95%, p < 0.034).

參考文獻


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被引用紀錄


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陳文瑩(2012)。建構模擬X-ray影像工具評估不同角度對影像的影響〔碩士論文,中原大學〕。華藝線上圖書館。https://doi.org/10.6840%2fcycu201200887
陳奕瑋(2012)。利用心臟電腦斷層影像評估動脈脈搏傳導速度〔碩士論文,中原大學〕。華藝線上圖書館。https://doi.org/10.6840%2fcycu201200130
馬銘徽(2010)。建構左心室四維動態模擬工具評估左心室心肌運動功能〔碩士論文,中原大學〕。華藝線上圖書館。https://doi.org/10.6840%2fcycu201000862
薛若盈(2009)。開發三維立體工具應用於多切面CT影像以分析左心室心臟功能〔碩士論文,中原大學〕。華藝線上圖書館。https://doi.org/10.6840%2fcycu200900338

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