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Gradation of diabetic retinopathy on reconstructed image using compressed sensing
摘要： This study explores neovascularisation and lesion detection in an integrated framework for gradation in diabetic retinopathy (DR). Imaging is assumed to be done from sub-sample measurements following compressed sensing. Blind estimation of the scale of the matched filter (MF) followed by fuzzy entropy maximisation is done for extraction and classification of the thick and the thin vessels. Mutual information (MI) between vessel density and tortuosity of the thin vessel class is maximised in two dimensions (2D) for neovascularisation detection. For lesion detection, MI between the maximum MF response and the maximum Laplacian of Gaussian filter response is jointly maximised in 2D. The outcomes are then combined in a common platform for gradation in DR. Simulation results demonstrate that 95% images of each of DRIVE, STARE and DIARETDB1 databases and 94% images of MESSIDOR database are correctly graded by the proposed method when 80% measurement space is considered.
关键词： compressed sensing,lesion detection,diabetic retinopathy,fuzzy entropy,mutual information,neovascularisation
更新于2025-09-23 15:21:21
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Multimodal imaging of foveal neovascularisation in diabetic retinopathy
摘要： Proliferative diabetic retinopathy is characterised by the growth of neovascular tissue, which almost always occurs at the optic disc and/or near the major nasal and temporal vascular arcades, sparing the foveal area.1 Finkelstein et al. ?rst described neovascular frond at the fovea arising from the perifoveal capillaries.2 A few other authors like Joondeph et al., Kurz et al., Rajagopal et al. and Seth et al. have also reported similar ?ndings.3–6 We report a rare case of unilateral foveal neovascularisation (NVF) in a middle-aged (40 years) woman of Asian origin who presented to us with chief complaints of blurring of vision in both eyes (left more than right) over the past few weeks, which was sudden in onset and progressive in nature. The patient had type 2 diabetes mellitus and dyslipidaemia for the past nine years. Her HbA1c was 10.5 per cent. On examination, her best-corrected visual acuity was 6/12 in the right eye and 6/24 in the left eye. The anterior segment was within normal limits for her age. Meticulous examination of the iris did not reveal any sign of neovascularisation. Posterior segment examination revealed proliferative diabetic retinopathy changes in both eyes with vitreous haemorrhage in the left eye only. The right eye was noted to have a whitish tuft at the fovea on biomicroscopy which turned out to be vascular in nature with distorted foveal avascular zone (FAZ) in both multicolor (Figure 1) and re?ectance (Figure 2) image. This was con?rmed with fundus ?uorescein angiography (confocal scanning laser ophthalmoscope-based; Figure 3) and spectral domain optical coherence tomography (Figure 4). Unlike previous reports, except for the recent report by Seth et al.,6 this patient had non-insulin-dependent diabetes mellitus. It is possible that this type of diabetes mellitus is not a predictor of NVF, but rather compromised ocular blood ?ow and duration and control of diabetes are predictors as reported by Summanen et al.7 In concordance with Finkelstein et al.,2 Joondeph et al.3 and Seth et al.,6 we noted macular ischaemia in our case, whereas Kurz et al.4 and Rajagopal et al.5 reported cases with perfused macula. Our case had unilateral NVF as reported by Joondeph et al.,3 Kurz et al.4 and Seth et al.,6 whereas Finkelstein et al.2 and Kurz et al.4 reported bilateral cases. We report for the ?rst time multimodal imaging of foveal neovascularisation in diabetic retinopathy. Limitations include a lack of early-phase fundus ?uorescein angiography imaging, green re?ectance, and optical coherence tomography angiography images. The early phase of ?uorescein angiography would have helped us with more effective visualisation of distorted FAZ and leakage from the NVF. Green re?ectance utilises a longer wavelength as compared to blue and has less absorption by the crystalline lens and xanthophyll pigments (at fovea) and therefore better delineates the fovea. In our case, this would have been the better imaging modality than blue re?ectance. Optical coherence tomography angiography beyond being non-invasive would have helped us to portray the FAZ and origin of foveal neovascularisation in a more desirable way, which we lacked.
关键词： multimodal imaging,diabetic retinopathy,foveal neovascularisation
更新于2025-09-09 09:28:46