Abstract
Purpose: :
To determine the validity of scanning laser ophthalmoscope in the retromode (RM-SLO) versus different imaging modalities in the diagnosis of diabetic macular edema (DME) and evaluation of single retinal lesions.
Methods: :
Prospective, comparative case series of 263 eyes (137 diabetics). Inclusion criteria were:any stage of untreated /treated diabetic retinopathy;5 imaging modalities of the macula carried out on the same day: color fundus photos, time domain optical coherence tomography (OCT), fundus autofluorescence (FAF), RM-SLO and fluorescein angiography (FFA); and no significant media opacities. Two masked retinal specialists independently graded all images. Agreement between RM-SLO and OCT, FFA and FAF in evaluating DME patterns and presence/absence of single lesions was evaluated by kappa statistics, sensitivity, specificity, observed proportional agreement (PA), PA in positive cases and PA in negative cases.
Results: :
The agreement in evaluating presence/absence of DME between RM-SLO and OCT, FFA and FAF was good: k=0.78 (Confidence Interval (CI) 0.68-0.88), k=0.75 (CI 0.65-0.85) and k=0.72 (CI 0.61- 0.83) respectively. The agreement for cystoid/non cystoid pattern of DME was almost perfect for all imaging modalities, k>0.8. The agreement for presence/absence of subfoveal neuroretinal detachment(SNE) was almost perfect between RM-SLO and OCT, (k=0.82,95% CI 0.67-0.96). SNE had no specific pattern on FFA or FAF. The agreement in evaluating single lesions on RM-SLO when graded as local depressions (retinal pigment alterations and laser scars) was almost perfect vs FFA and FAF, (k>0.8). For lesions graded as elevations (leaking microaneurysms and drusen) the agreement was perfect vs FFA (k=1), and fair for OCT and FAF, (k=0.3).Sensitivity and specificity of RM-SLO in evaluating DME was 96.7% and 79.6% vs OCT, 98% and 71.2% vs FFA and 96.6% and 70.9% vs FAF. Retinal thickness of 233 micron was the cut-off value for detection of DME by RM-SLO.
Conclusions: :
The combined use of non invasive imaging techniques can improve the diagnostic interpretation of different aspects of DME, probably avoiding invasive tests.
Keywords: edema • diabetic retinopathy • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)