運用紅外線影像處理於頸動脈狹窄之評估

Using Infrared Thermal Image in the Evaluation of Carotid Stenosis

李愛先(Ai-Hsien Li)

指導教授 ： 翁清松

中原大學/工學院/生物醫學工程學系/博士(2008年)

https://doi.org/10.6840/cycu200800249

摘要

台灣地區缺血性腦中風是重要的死亡原因，其中一個重要致病原因就是頸動脈狹窄。然而傳統評估方法，不論是血管動脈攝影、頸動脈都卜勒超音波，核磁共振血管攝影，都有耗時較長以及執行不便的缺點，不適合作為大規模篩檢疾病的影像工具。根據文獻上的証據，同側臉部平均溫度的測量，可以推測血流量血流分布變化，本研究的目的是在利用紅外線攝影機取得的熱影像，藉由紅外線影像處理和分析的技術來預測病人頸動脈的狹窄程度。
在恆溫控制的環境下，本實驗利用攜帶型紅外線攝影機拍攝正常志願者(包括健康志願者8名以及其他疾病病患業經頸動脈排除者32名)和頸動脈狹窄病患(在不同階段共57名)的側臉熱影像，擷取灰階熱影像檔案儲存到電腦以備分析。另一方面，用Borland C++ Builder 6.0為開發工具，完成半自動圈選臉部輪廓，以及全自動偵測的程式軟體；以便計算其平均溫度和各部位溫度分布的標準差。
我們進一步研究分析結果和受試者的頸動脈超音波(臨床上操作耗時)，與頸動脈血管攝影檢查結果比較，頸動脈超音波不僅耗時且有介入性的危險性，証明彼此強烈相關性。我們更發現正常人的面部溫度平均溫度可以用攝氏三十二度作為切分點，可以得到合理的快速測量特異度超過七成71%~83%，負向預測值在小於33℃左右可以得到60%以上。
未來希望利用研究所開發的臉部溫度最高溫最低溫自動決定以及等溫度曲線繪圖功能。進一步建立正常與不正常頸動脈血管狀況和面部血流資料的資料庫。同時所開發的軟體，可以有效作為快速評估頸動脈血流的篩檢性方法，並做為未來追蹤的基礎。

關鍵字

紅外線影像處理 ； 頸動脈狹窄 ； 平均溫度 ； 灰階熱影像 ； 缺血性腦中風

並列摘要

As a major cause of ischemic stroke, Carotid artery stenosis still calls for a effective screening method for its diagnosis. The traditional image modalities, such as carotid angiography, carotid duplex ultrasound, and magnetic resonance angiography, are not good for screening for their invasiveness and time-consuming process. According to the evidence in the literature, the ipsilateral thermograph could predict the facial blood flow distribution and the carotid condition indirectly. We acquire infrared thermograph to predict the possibility of carotid artery stenosis by Infrared thermograph processing and analysis.
In the temperature-constant room, we acquired the side facial thermograph of carotid-normal individuals (8 health volunteers and 32 patients of other diseases) and carotid stenotic patients (totally 57 patients).We used Borland C++ Builder 6.0 as platform to complete a software for image analysis. We achieved automatic and semi-automatic software capable of processing grey scale thermograph and calculating the mean temperature and standard deviation. Then we also compare the image parameters with the traditional image modalities. Thereafter, strong association was disclosed between them.
Besides, after the comparative analysis of the parameters between various image methods, we set the threshold temperature to 32 degree as a cut-off value, and obtained reasonable specificity of diagnosis more than 70% (0.71-0.83).
We wish to continue our work to utilize the automatic border/isothermal curve demarcation software to establish a much bigger data base in the future, and it would be beneficial to not only the detection of carotid stenosis, but the prevention of clinical events.

並列關鍵字

Mean temperature ； Infrared thermograph processing and analysis ； Grey scale thermograph ； Ischemic stroke ； Carotid stenosis

參考文獻

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