Quantification of Retinal and Choriocapillaris Perfusion in Different Stages of Macular Telangiectasia Type 2

Abstract

PURPOSE. To quantify the retinal and choriocapillaris perfusion in different disease stages of macular telangiectasia type 2 (MacTel) using optical coherence tomography-angiography (OCT-A). METHODS. We examined 76 eyes of 76 patients and 24 eyes of 24 age-related controls. Participants underwent multimodal imaging, including OCT and OCT-A. Patients' eyes were divided into three groups considering predefined criteria from funduscopy, OCT, and fluorescein angiography, thus reflecting the disease severity (''early,'' ''advanced,'' and ''neovascular''). Quantitative analyses of vessel density (VD), skeleton density (SD), and fractal dimension (FD) were conducted in the superficial and deep retinal plexus and in the avascular layer. The choriocapillaris was analyzed for mean signal intensity and percentage of nondetectable perfused choriocapillaris-area (PNPA). RESULTS. The deep retinal plexus showed a progressive decrease of mean VD, SD, and FD in the temporal parafovea in all disease stages. In the superficial layer, VD, SD, and FD were significantly decreased in the temporal parafovea of advanced and neovascular stages, while these parameters did not differ from controls in early stages. In MacTel, signals of blood flow were also detectable at the level of the avascular layer and showed a significant increase with disease progression. The choriocapillaris in MacTel showed a significant increase of mean PNPA and a decrease of mean signal intensity in comparison to controls. These findings were consistent in all disease stages. CONCLUSIONS. Quantitative OCT-A data show a progressive rarefication of the retinal microvasculature in MacTel. We propose an altered choriocapillaris perfusion as a possibly early alteration of the disease.

Hyperreflectivity on Optical Coherence Tomography in Macular Telangiectasia Type 2

“…Several previous studies have described various morphological changes that would fit into the category of hyperreflectivity on OCT. [6][7][8][9] Possible anatomical correlates of hyperreflectivity include altered retinal capillaries, retinal-choroidal anastomoses, migrating pigment cells, and neurodegenerative processes. 6,[9][10][11] Optical coherence tomography angiography has been helpful as an imaging tool for illustrating disease-associated changes of the retinal and choroidal microvasculature, 12,13 permitting a detailed visualization of neovascularizations secondary to MacTel. 14 Unlike OCT, however, OCT-A is currently not widely available in clinical practice.…”

Optical Coherence Tomography Angiography Findings in Patients With Acute Syphilitic Posterior Placoid Chorioretinopathy

“…The flow voids of our pretreatment and posttreatment cases were greater than previously reported normal choriocapillaris flow voids: 11.5% to 17.7%. 5,11 However, a comparison cannot be made because these normative values were derived from 3 Â 3-mm scans and we used 8 Â 8-mm scans. A described normative value and longer follow-up will allow comparison of normal, pretherapy and posttherapy eyes to assess whether residual choriocapillaris dysfunction persists despite normalization of funduscopic examination, as may be suggested by the difference in posttherapy choriocapillaris flow voids in the right (30.7%) and left eye (33.9%) of case 1.…”

Mapping of choriocapillaris vascular density in young and aged healthy subjects

“…Afterwards, CC VD pictures were analysed with specifically designed software. First, every pixel was codified into a number following this scale: dark blue (1), blue (2), light blue (3), cyan (4), green (5), yellow (6), orange (7), red (8) and dark red (9). Then, pictures were divided into a grid of 900 squares (30 rows and 30 columns) with the same size.…”

“…It has been found that CC plays a major role in different retinal pathologies such as age-related macular degeneration, 4,5 systemic hypertension,6 myopic maculopathy, 7 macular telangiectasia type 2, 8 retinal dystrophies, 9 or inflammatory choriocapillaropathies. 10 Choroidal vascularization remains difficult to measure due to light scattering when passing through the overlaying tissues and the retinal pigmentary epithelium (RPE).…”