당뇨망막병증과 망막정맥폐쇄 질환에서 보이는 망막비혈류 부위 및 망막중심오목 무혈관 부위 발견을 위한 공초점 무적색 청색광 이미징을 이용한 새로운 방법

Abstract

목적: 본 연구의 목적은 망막 비관류 부위(Retinal nonperfusion)와 망막중심오목 무혈관 부위(Fovea avascular zone, FAZ)의 발견을 위한 새로운 비침습적 이미징 방법으로서 공초점 무적색 청색광 이미징(confocal blue reflectance red-free imaging)을 보고하고 당뇨망막병증과 망막정맥폐쇄 증에서 기존의 전통적 검사방법인 형광안저촬영과 그 효과를 비교하는 것이다.

대상과 방법: 후향적 관찰 단면연구로 망막비관류 부위 (Nonperfusion study)와 망막중심오목 무혈관 부위 (FAZ study)를 찾는 연구를 각각 진행하였다. 당뇨망막병증이나 망막정맥폐쇄증이 있는 환자들 중 nonperfusion study에는 54안이, FAZ study에는 70안의 대상안을 모았다. 모든 환자들은 공초점 무적색 청색광 이미징과 형광안저촬영을 촬영하였다. 이미지 분석을 위하여 2명의 독립된 망막 전문의가 각각 기기에서 촬영된 이미지에서 망막비관류 또는 망막중심오목 무혈관부위를 직접 결정하여 그리고 이미지 프로세싱 과정을 거친 후 면적과 일치도를 구하여 두 이미지를 비교하였다.

결과: 망막비혈관 부위와 망막중심오목 무혈관 부위에 대하여 각각의 기기로 촬영한 이미지를 비교한 결과 면적에 있어서는 두 이미지가 높은 연관성 (r > 0.9)을 보였다. 두 기기에 촬영된 이미지를 서로 비교 분석한 결과 nonperfusion study (P=0.563, overlapping ratio 0.76)나 FAZ study (P=0.925, overlapping ratio 0.77) 모두에서 면적, 일치도가 통계적 차이를 보이지 않았다.

결론: 공초점 무적색 청색광 이미징은 망막비관류 부위나 망막중심오목 무혈관 부위를 찾는 데 있어 단순하면서도 안전한 비침습적 방법이다. 당뇨망막병증이나 망막정맥폐쇄 질환 같은 망막혈관 질환의 스크리닝, 초기 진단 및 경과관찰, 치료 방법의 결정에 필수적인 망막 비혈관 부위나 망막줌심오목 무혈관 부위의 발견 및 정량화에 있어 기존의 침습적 방법을 대체하는 새로운 비침습적 방법이 될 수 있다. |Purpose: To report confocal red-free blue reflectance imaging as a novel noninvasive imaging modality for detection of retinal nonperfusion and fovea avascular zone (FAZ) and to compare the effectiveness of this red free imaging with fluorescein angiography (FA) in diabetic retinopathy (DR) and retinal vein occlusion (RVO).

Methods: This retrospective observational cross-sectional study was performed in two arms: a “nonperfusion study” and a “FAZ study”. A total of 54 eyes in the nonperfusion study and 70 eyes in FAZ study with DR or RVO were enrolled. All patients underwent red-free blue reflectance imaging and FA using a confocal scanning laser ophthalmoscope (cSLO). For all patients, the macular, mid-peripheral retinal nonperfusion and FAZ were identified in both confocal red-free and a corresponding FA image and delineated by two independent readers. The correspondence of the two imaging methods was evaluated by the comparison of the size of the delineated area and obtaining overlapping ratio after image processing.

Results: The image analysis showed a high correlation (r > 0.9) in the mean size of retinal nonperfusion and FAZ between red-free and corresponding FA images with DR or RVO. Reliable agreement between two methods was confirmed by the comparison of size (P=0.563 in nonperfusion study, P=0.925 in FAZ study) and overlapping correspondence (overlapping ratio, 0.76 in nonperfusion study, 0.77 in FAZ study) of the delineated area.

Conclusions: Confocal red-free imaging is a simple, safe and noninvasive method for plotting the retinal nonperfusion and FAZ effectively. This procedure, first reported herein, has the potential to be used for noninvasively detecting and quantifying retinal nonperfusion and FAZ in screening, initial evaluation, treatment decision and follow up of progressive ischemic retinopathy such as DR and RVO.; Purpose: To report confocal red-free blue reflectance imaging as a novel noninvasive imaging modality for detection of retinal nonperfusion and fovea avascular zone (FAZ) and to compare the effectiveness of this red free imaging with fluorescein angiography (FA) in diabetic retinopathy (DR) and retinal vein occlusion (RVO).

Methods: This retrospective observational cross-sectional study was performed in two arms: a “nonperfusion study” and a “FAZ study”. A total of 54 eyes in the nonperfusion study and 70 eyes in FAZ study with DR or RVO were enrolled. All patients underwent red-free blue reflectance imaging and FA using a confocal scanning laser ophthalmoscope (cSLO). For all patients, the macular, mid-peripheral retinal nonperfusion and FAZ were identified in both confocal red-free and a corresponding FA image and delineated by two independent readers. The correspondence of the two imaging methods was evaluated by the comparison of the size of the delineated area and obtaining overlapping ratio after image processing.

Results: The image analysis showed a high correlation (r > 0.9) in the mean size of retinal nonperfusion and FAZ between red-free and corresponding FA images with DR or RVO. Reliable agreement between two methods was confirmed by the comparison of size (P=0.563 in nonperfusion study, P=0.925 in FAZ study) and overlapping correspondence (overlapping ratio, 0.76 in nonperfusion study, 0.77 in FAZ study) of the delineated area.

Conclusions: Confocal red-free imaging is a simple, safe and noninvasive method for plotting the retinal nonperfusion and FAZ effectively. This procedure, first reported herein, has the potential to be used for noninvasively detecting and quantifying retinal nonperfusion and FAZ in screening, initial evaluation, treatment decision and follow up of progressive ischemic retinopathy such as DR and RVO.