Non‐invasive optical coherence tomography angiography: A comparison with fluorescein and indocyanine green angiography in normal adult dogs and cats

Abstract

While the retinal vasculature can be assessed by simple funduscopy, a more detailed assessment can be performed by conventional angiography using dyes such as fluorescein or indocyanine green. The development of optical coherence tomography angiography (OCT-A) allows a non-invasive detailed examination of posterior segment vasculature. The purpose of this prospective study was to compare imaging of posterior segment vasculature in normal dogs and cats using OCT-A, fluorescein angiography (FA), and indocyanine green angiography (ICGA). Methods: Eight adult funduscopically normal dogs and 13 funduscopically normal cats were included in the study. Retinal vasculature was assessed by OCT-A followed by ICGA then FA. Regular fundus imaging was also performed. Results: High-resolution images of the different vascular layers within the retina and choroid could be acquired using OCT-A in both dogs and cats. The technique provided more detail than obtained with FA/ICGA. However, artifacts/errors can occur during OCT-A image acquisition/analysis/interpretation and must be considered. Furthermore, OCT-A only allows for a limited field of view compared to FA/ICGA. Conclusions: Optical coherence tomography angiography is a new non-invasive posterior segment imaging technique that is complementary to traditional dyebased angiographic techniques. Detailed imaging of the dog and cat posterior segment can be achieved under general anesthesia. OCT-A provides additional detail of the vasculature and can clearly demonstrate the anatomical depth of the imaged vessels. There are, however, some limitations to this new technique that may be overcome by future technological advances.

Use of direct fluorescein sodium lymphography for thoracic duct identification in a dog with idiopathic chylothorax

“…12 In veterinary medicine, fluorescein sodium has also been used for angiography, and one report described the use of intravenous fluorescein sodium injection to guide the resection of intracranial lesions in 22 dogs. [13][14][15][16] Fluorescein sodium fluorescence microscope-integrated lymphangiography has been reported in human medicine once in 2015. The goal of the case report was to assess the lymphatic drainage pathway and patency in a patient treated for secondary lymphedema by lymphaticovenular anastomoses.…”

“…Fluorescein sodium has also been used to localise multiple muscular ventricular septal defects during open heart surgery and to confirm the presence of any residual defects 12 . In veterinary medicine, fluorescein sodium has also been used for angiography, and one report described the use of intravenous fluorescein sodium injection to guide the resection of intracranial lesions in 22 dogs 13–16 …”

Bilateral corneal dermoids associated with bilateral choroido–scleral colobomas in a cat: retinographic and optical coherence tomography study with surgical outcome and follow–up

“…[16][17][18] Recently, it has been published that outer retinal band and choriocapillaris can be identified in healthy dogs and cats, 19 and different vascular layers of the retina and choroid are nicely evaluated by OCT-A in cats. 20 The present report describes the clinical case of bilateral corneal dermoids associated with bilateral choroidoscleral colobomas in a cat, its SD-OCT fundus evaluation, the surgical outcome and the follow-up of lesions up to 18 months. A review of literature suggests that it is the first case reported of such an association in a domestic cat.…”

“…Several studies have shown that spectral domain OCT (SD‐OCT) is a reliable method to evaluate different retinal layers and optic nerve morphology in colobomas in dogs, 15 in healthy or glaucomatous cats 16–18 . Recently, it has been published that outer retinal band and choriocapillaris can be identified in healthy dogs and cats, 19 and different vascular layers of the retina and choroid are nicely evaluated by OCT‐A in cats 20 …”