Agreement of Heidelberg Retina Tomograph II Macular Edema Maps with Clinical Evaluation and Fluorescein Angiography in Diabetic Maculopathy

Abstract

Abstract: : Purpose: To undertake a cross-sectional investigation of the agreement between the Heidelberg Retina Tomograph (HRT) II derived macular edema maps (MEM), contact lens stereo fundus biomicroscopy (FB) and fluorescein angiography (FA) in patients with diabetic maculopathy. Methods: The sample comprised 23 patients with diabetic maculopathy. They had a mean age of 56.95 years (range 43-67 years) and mean duration of diabetes of 13.26 years (range 5-30 years). All patients underwent FB, HRT II imaging and FA. The MEMs of the HRTII were reviewed and the areas of elevated edema index were identified using a pre-defined grid (500, 1000 and 1500 µm radii circles centred on the fovea and divided into X-like quadrants). A retinal specialist mapped the area of retinal thickening seen by FB onto a similar grid that also incorporated the vascular map. The areas of leakage in the late stage FA pictures were similarly recorded. The areas of agreement (overlap) and disagreement (no overlap) for each technique were determined using the pre-defined grid, e.g. if 8 of the 9 zones of the grid agreed between techniques the score would be 88.9%. Results: The MEMs showed an elevated edema index in 21 of 23 eyes. Clinical examination showed thickening in 11 of 23 eyes and FA showed leakage in 17 of 23 eyes. For the 11 eyes in which edema was noted clinically, the MEMs showed an agreement of 85.45%; 100% agreement was seen in 6 eyes. The HRT agreed with the presence of FA leakage in 15 eyes; agreement was 72.46%. MEMs gave an elevated edema index in the absence of clinical edema in 11 patients and in the absence of FA leakage in 4 patients. MEMs did not detect edema in 1 patient that was clinically detected & showed FA leakage. Conclusion: HRTII macular edema maps demonstrated good agreement with clinical assessment in those patients with clinically detectable edema, but tended to detect a greater extent of edema, and in more patients. The number of patients with elevated edema index and FA leakage was high and showed good agreement.

Keywords: diabetic retinopathy • imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, S