Abstract
Purpose: :
Fluorescence Angiography (FA) remains the method of choice for the diagnosis and follow-up of a broad spectrum of retinal vascular abnormalities secondary to diabetes mellitus. Recently, our group showed distinct leakage patterns observable in patients with diabetic macular edema as seen in spectral domain optical coherence tomography (SD-OCT). We now want to describe alterations to the retinal architecture associated with perifoveal vascular leakage.
Methods: :
20 consecutive patients with diabetic retinopathy secondary to diabetes mellitus type 2 were examined using the FA+OCT mode of the (Heidelberg Engineering Spectralis HRA+OCT) during one same-day examination. FA images were then analyzed for diffuse, hyperfluorescent areas surrounding retinal vessels and microaneurysms and the corresponding areas on the SD-OCT scans were observed using the Heidelberg Engineering Eye Explorer Software.
Results: :
In all cases, structural alterations could be detected in the SD-OCT scans corresponding to locations of diffuse hyper-fluorescence in FA representing vascular leakage. SD-OCT images showed different stages of patho-morphological changes including mild signal dispersals of the SD-OCT signal or very small cystic spaces confined to the retinal inner nuclear layer (INL), cystic spaces and diffuse SD-OCT signal dispersal in the outer nuclear layer (ONL) and cystic spaces throughout all retinal layers. Interestingly, all locations with significant retinal thickening showed alterations in the outer nuclear layer, whereas significantly less retinal thickening was measured at locations with changes confined to the inner retinal layers.
Conclusions: :
Perifoveal vascular leakage causes morphological alterations observable in spectral domain optical coherence tomography. The detected changes ranged from mild signal dispersal and cystic spaces confined to the INL to signal dispersal and cystic spaces in the INL and ONL, the latter case being more commonly associated with local edema in the affected retinal area.
Keywords: diabetic retinopathy • edema • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)