Die Bedeutung der digitalen Integrationsmethode (DIM) von OCT und FLA für die klinische Anwendung

Abstract

We describe the establishment of a new digital integration method (DIM) for the anatomically precise and objective correlation of OCT and FLA. The aim of the study was to evaluate the clinical impact of DIM and deduce possible new knowledge in unclear angiographic findings. DIM uses a newly developed software for the integration of OCT and FLA images of the same date. Corresponding vascular bifurcations and OCT scan position are marked in OCT and FLA images. Pathological areas in OCT or FLA can be marked and compared. A fundus enhancement system (FES) was developed for a better fundus image quality in OCT. Using a retinal tracking system (RTS) eye movements can be compensated. DIM was evaluated in 225 patients with macular diseases. Using FES, the DIM was successful in 95 % of the patients in contrast to 25 % without FES. Using the video system of RTS eye movement artefacts could be compensated in all patients. Cases with clear angiographic findings showed a high correspondence (66 %) with the OCT findings. A discrepancy between FLA and OCT findings was found in 33 %, especially in leakages of unknown origin. DIM was of high value in age-related macular degeneration (AMD), detecting a heterogeneous morphology of serous, solid RPE detachments, retinal cystoid formation and choroidal neovascularisation (CNV) and differentiating it in a precise topography. The lesion size of classic CNV with a hypofluorescent halo was in OCT always larger than in FLA. Through the correction of the eye movement artefacts by DIM and FES, a fundamental weak point in the previous OCT pictures is counterbalanced. Using DIM the OCT scan position for the follow-up can now be assessed in a safe and reliable manner which is mandatory for the evidence of OCT studies. The detection of precise morphology (serous RPE detachments) in angiographically unclear phenomena can lead to treatment consequences, e. g., avoiding contraindicated areas in photodynamic therapy. Using the new morphological information new knowledge is obtained on uncertain angiographic phenomena by this integration method (DIM).