Article
Optimisation of retinal assessment using a new digital integration method for OCT and FLA/ICG
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Authors
Published: | September 22, 2004 |
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Outline
Text
Objective
Up to now, an inter-observer variability in the correlation of OCT (optical coherence tomography) with FLA (fluorescein angiography) / ICG (indocyanine green angiography) findings could not be avoided. A newly developed integration software for OCT and FLA/ICG allows now an exact integration of findings obtained by these different diagnostic techniques.
Methods
Digital fundus photographs of FLA or ICG were made to coincide with fundus photographs of optical coherence tomograms using a mapping procedure. Mapping is made by placing reference points manually to vascular crossings and rectifying with the help of a special software. 70 patients suffering from different macular diseases underwent an FLA/ICG (including redfree photographs) and OCT examination followed by integration.
Results
The quality of the fundus images obtained with OCT proved to be the limiting factor for integrating FLA/ICG findigs and OCT findings, because the vascular crossing in the fundus image determine the reference points. In 50 of 70 patients, the angiogramms could be precisely correlated with the optical coherence tomograms. This was especially beneficial for patients with pathologic findings of unclear origin such as leakage in occult choroidal neovascularisation (CNV). In most cases, the size of the CNV with intraretinal cysts found on OCT was larger than that found in FLA. In central serous chorioretinopathy, it was possible to show that the origin of the leakage in FLA and the focus of the serous detachment of the retinal pigment epithelium on OCT are identical.
Conclusions
A good quality of fundus photographs on OCT requires optimal illumination and constrast parameters. Especially for patients with occult CNV or occult leakage in FLA or ICG (perfusion topography), a precise integration of the OCT findings (tomography) may be beneficial. Pathologic structures can be clearly demarcated. This may contribute to a more precise treatment strategy, e.g. laser coagulation or photodynamic therapy (boundary of pigment epithelium detachment).