Optical coherence tomography angiography (OCTA) as a new diagnostic tool in uveitis

Abstract

Background The broad spectrum of uveitis disorders requires a multimodal imaging approach in the daily practice of an ophthalmologist. As inflammatory conditions, they have in common an alteration in leukocyte migration. In this context, optical coherence tomography angiography (OCTA) might be of great value for diagnosing or following up patients with these disorders. To date, OCTA has rather been used as an additional tool besides the well-established diagnostic imaging tools, but its complementary diagnostic features become increasingly relevant, to follow disease activity and treatment response and for the understanding of pathomechanisms of various uveitis types. This review summarizes the possible applications of OCTA and its advantages and disadvantages as opposed to dye-based angiographies in uveitic diseases. Main body Hitherto gold standards in the diagnostic workup of posterior or intermediate uveitis have been angiography on a dye-based method, which is fluorescein or indocyanine green. It gives information about the status of the blood-retinal barrier and the retinal and choroidal vasculature by visualizing diffuse leakage as a state of inflammation or complications as an ischemia or choroidal neovascularization. As noninvasive methods, fundus autofluorescence depicts the status of metabolic activity of the retinal pigment epithelium and OCT or enhanced depth imaging OCT, respectively, as a depth-resolving imaging method can supply additional information. OCTA as a non-invasive, depth-resolution imaging tool of retinal and choroidal vessels adds detailed qualitative and quantitative information of the status of retinal and choroidal vessels and bridges the gap between the mentioned conventional diagnostic tools used in uveitis. It is important, though, to be aware of its limitations, such as its susceptibility to motion artifacts, limited comparability among different devices, and restricted contribution of information regarding the grade of disease activity. Conclusion OCTA as a non-invasive, depth-resolution imaging tool can give qualitative and quantitative information about the status of retinal and choroidal vessels, but also has certain limitations. Employing OCTA as a complementary rather than exclusive tool, it can give important additional information about the macro- and microvasculature under inflammatory circumstances. Thereby, it also contributes to the understanding of the pathophysiology of various uveitis entities.

New findings useful for clinical practice using swept-source optical coherence tomography angiography in the follow-up of active ocular toxoplasmosis

“…The patient will be followed closely because of the risk of CNVM exudation. Although subclinical CNVM has already been described with SS-OCTA in eyes with multifocal choroiditis [40,46], to our knowledge the current study is the first to describe a subclinical CNVM in a patient with OT.…”

“…A majority of inflammatory CNVMs are type 2 lesions with abnormal growth of vasculature into the outer retinal space [45]. However, inflammatory CNVM does not necessarily present with a sub-or intraretinal fluid on OCT and may just show an increase in subretinal hyperreflectivity [40]. One current patient presented with a subclinical type 2 CNVM adjacent to a toxoplasmic lesion.…”

“…Although this entity is uncommon during active retinochoroiditis, it has been described previously [ 37 , 38 ]. Case reports about CNVM in toxoplasmosis have confirmed the use of OCTA for CNVM secondary to OT, especially because FA findings can be difficult to interpret in a scarred area [ 26 , 39 , 40 ]. Previous OCTA studies have described subclinical type 1 macular neovascularization (MNV) in patients with age-related macular degeneration (AMD), chronic central serous chorioretinopathy and polypoidal choroidal vasculopathy [ 41 – 43 ].…”

Ocular involvement in Behçet’s disease: relevance of new diagnostic tools

“…This takes place particularly when the recurrent inflammatory flares of the disease translate to damage of the posterior eye segment, leading to a permanent injury of the retinal vasculature [ 1 ]. The early identification of disease activity is still challenging, although its prompt recognition can decrease the risk of poor visual outcome [ 2 ]. Spectral domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCTA) could complement the nformation provided by the standard fluorescein angiography (FA).…”

“…FA, the current reference method for the assessment of posterior ocular involvement in BD, allows only a two-dimensional study of the superficial retinal circulation, and frequently, the damage to retinal vessels limits the reliable assessment of disease activity [ 3 ]. SDOCT better defines the morphology of the retina, whereas OCTA can evaluate its superficial and deep circulation separately, simulating angiographic images [ 2 , 4 ]. Through these techniques, we identified the ocular involvement of our patient, whose deep retinal capillary plexus was severely affected.…”