Choroidal macrovessel: Optical coherence tomography angiography and imaging features

A 65-year-old white woman was referred to us to rule out a nematode infestation in the right eye. She was asymptomatic, and best-corrected visual acuity was 20/20 in both eyes. On examination, there were no signs of active inflammation in either eye, and intraocular pressure was 15 mmHg in both eyes. Past medical history was unremarkable and the patient denied recent travel to endemic areas.

Fundus examination revealed a deep serpentine shaped subretinal track at the posterior pole of the right eye. Multimodal retinal imaging, including fundus autofluorescence, enhanced-depth imaging optical coherence tomography (EDI-OCT), fluorescein angiography (FA), and indocyanine green angiography (ICGA), was suggestive of a choroidal macrovessel [Figs. 1–3]. The diagnosis was further supported by enface OCT that showed that the reflectivity of the macrovessel was similar to that of the physiological adjacent choroidal vessels and by OCT angiography (OCT-A) that revealed a relatively slow flow inside the macrovessel [Fig. 4].

Figure 1.

(a) Ultra-wide field color imaging shows a dilated, tortuous choroidal vessel, originating in the temporal foveal region. (b) Ultra-wide field fundus autofluorescence (AF) reveals increased AF along the length of the vessel

Figure 3.

Enhanced-depth imaging optical coherence tomography scan of the macrovessel shows hollowness of the macrovessel (asterisks), elevations of the retinal pigment epithelium, and a cleft of subretinal fluid

Figure 4.

(a) Optical coherence tomography angiography of the choroid reveals a relatively low flow inside the macrovessel (arrow). (b) En face optical coherence tomography of the choroid shows that the reflectivity of the macrovessel is similar to that of the physiological adjacent choroidal vessels (asterisk)

Figure 2.

(a) Fluorescein angiography shows hyperfluoresence along the course of the vessel. (b) Indocyanine green angiography shows early filling of the vessel (yellow asterisks)

Discussion

Choroidal macrovessel was described for the first time by Lima and associates[1] in 2011. In the original report, the authors described an anomalous choroidal vessel with normal indocyanine green fluorescence in the early phase with hypofluorescence throughout its course in the late phase, without leakage.[1]

Different nematodes and, occasionally, diffuse unilateral subacute neuroretinitis may cause subretinal atrophic and cicatricial tracts in the fundus that may mimic a choroidal macrovessel.[1] However, in our case, there was neither history of possible exposure to nematodes infestation nor signs of ocular inflammation. In addition, multimodal retinal imaging features were entirely consistent with a diagnosis of choroidal macrovessel.[1,2,3,4,5,6,7,8] Given its recent description, prevalence and clinical course of choroidal macrovessel are unknown, and only a few cases have been reported in the current literature.[1,2,3,4,5,6,7,8]

We report multimodal retinal imaging including OCT, OCT-A, and traditional retinal contrast imaging, namely FA and ICGA. In line with the previous reports,[1,2,3,4,5,6,7,8] OCT is able to detect the macrovessel in the choroid by showing hollowness along the course of the vessel and elevations of the overlying retinal pigment epithelium. In our case, a cleft of subretinal fluid was also detected, and this may indicate leakage from the macrovessel, as previously hypothesized.[8]

OCT-A has been a recent breakthrough in the imaging of the retina and has made it possible to study the retinal and the choroidal vasculature without the injection of the dye. Moreover, OCT-A technology allows simultaneous acquisition of en face OCT scan, which has been shown to be useful for the detection of the choroidal macrovessel.[2]

The use of en face OCT and OCT-A in choroidal macrovessel has been reported in single photo essays which have not provided correlation with FA and ICGA.[2,3] Therefore, this report shows for the first time excellent correlation between identification of the macrovessel on ICGA, OCT-A and en face OCT.

In conclusion, our case supports the use of en face OCT and OCT-A as non-invasive imaging technique modalities to diagnose and monitor the clinical course of choroidal macrovessel.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.