Mirau 全域式光學同調斷層掃描術結合螢光顯微術在皮膚黑色素癌診斷上的應用

Abstract

Mirau全域式光學同調斷層掃描儀(FF-OCT)為具有非侵入式、樣本不須特別製作及三維空間解析度佳等特性，近年來嘗試應用在皮膚科的臨床醫學研究上，然而有部分案例較難直接以此準確判定。螢光顯微術利用染劑標定欲觀察的對象，可以只針對特定目標來成像。我們以螢光顯微術輔助光學同調斷層掃描術，利用針對抗體MART-1結合的螢光抗體Cyanine Cy™3來標定黑色素癌細胞，同時我們也將相同的樣品進行大面積光學同調斷層掃描，並且請台大醫院皮膚科及病理科醫師協助圈選癌細胞區域；以相同檢體之H&E stain作為比對標準，經研究發現結合螢光顯微術可以大幅降低誤判情況。 實驗規劃分成二種比對模式，第一種是比較醫師們圈選大面積光學同調斷層掃描影像的癌症區域和H&E stain的差異，利用Cohen's κ檢定、卡方檢定、ϕ相關係數、敏感性、專一性、陽性預測值和陰性預測值量化差異；第二種是比較結合螢光顯微術之後和H&E stain的差異，並利用上述相同方式量化差異。實驗結果發現皮膚科醫師對癌症區域認定差異很大，表示和H&E stain一致性的Cohen's κ從0.74到不一致，ϕ相關係數由0.77到0.22，實證醫學指標也顯示有的皮膚科醫師辨認很準確，有的醫師幾乎辨認錯誤。病理科醫師圈選十分相近，然而切片判斷經驗豐富的病理科醫師之結果和H&E stain不太一致，ϕ相關係數也小於0.3。結合螢光顯微術之後，Cohen's κ檢定、ϕ相關係數及實證醫學指標都超過0.9。 本研究使用結合螢光顯微術的Mirau全域式光學同調斷層掃描儀，利用免疫螢光染色判斷黑色素癌細胞，發現比未結合前還優異的結果，與H&E stain的相關性及一致性都超過0.9，此一結果顯示本研究之光學系統與H&E stain十分接近，在臨床應用上極具潛力。

Mirau-based full-field optical coherent tomography (Mirau FF-OCT) is a three-dimensional (3D) optical imaging system that has characteristics of non-invasive, no specific demand in preparing the sample and high spatial resolution. It has been tried to be used in clinically dermatology research lately, but part of cases are hard to distinguish lesion correctly. Fluorescence microscopy (FM) uses fluorescence dye to label biological molecule of interest, so it can only present image of specific target. We use immunofluorescence techniques to aid OCT in melanoma diagnosis. We applied labeled antibodies Cyanine Cy™3 to bind to target antibodies MART-1 for melanoma detection. We also obtained large area OCT image with exactly the same specimen, and with the help of dermatologists and pathologists circled the area on the image which showed the presence of melanoma. The H&E stain of the sample is needed as standard contrast. Our research reveals that combining fluorescence microscopy can reduce the case of misidentification dramatically. We did the experiment with two comparison methods. The first method was compared the difference in circled areas by pathologists or dermatologists between large area OCT images and H&E stains image. The second method was compared the difference in detection areas which had been involved by melanoma between combination of OCT with FM and H&E stain. We evaluated the degree of differences by using Cohen's κ, chi-square test, phi coefficient, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Results showed that dermatologists' recognition as tumor area varied greatly. κ statistic, a measure of agreement, ranged from 0.74 to disagreement and phi coefficient ranged from 0.77 to 0.22. The results of diagnostic test also showed that some dermatologists recognized tumor areas very well but others did not. The circled areas by pathologists were very close. However, the results from experienced pathologists were not in agreement with H&E stain perfectly and phi coefficient was also less than 0.3. After combining FM, Cohen's κ, phi coefficient and the results of diagnostic test are greater than 0.9. In this study, by utilizing the combination of Mirau FF-OCT with FM and immunofluorescence techniques, we obtain better results than individual methods in detecting melanoma. The agreement and correlation with H&E stain are all greater than 0.9. These demonstrate that our optical system is very close to H&E stain and has great potential on clinical application in the future.