Anatomical and functional correlation in Susac syndrome: multimodal imaging assessment

Abstract

BackgroundSusac’s syndrome (SuS) is an uncommon disease characterized by retinal microangiopathy that may be assessed more accurately with optical coherence tomography angiography (OCTA), a new imaging technique which provides a retinal microvasculature map. The purpose of this case report is to describe the multimodal imaging findings of SuS correlating OCTA with functional tests.Case presentationRetrospective review of one case with clinical and imaging evidence of SuS. Color fundus photograph, fluorescein angiography (FA), OCTA, microperimetry (MP) and visual field (VF) tests were analyzed at the time of presentation and at 1- and 6-month visit following initiation of treatment. The study patient underwent standard treatment for SuS. The patient age was 31 year-old and the baseline visual acuity was 20/60 and 20/20 in the right and left eyes, respectively. At presentation, FA showed branch retinal arterial occlusion within the macular area of the right eye and vascular leakage in the periphery of the left eye. OCTA demonstrated areas of superficial and deep retinal vascular plexuses hypoperfusion in both eyes. The OCTA segmentations in the outer retina and choriocapillaris were normal. The low VF and MP sensitivity signals precisely corresponded to the topography of decreased vascular perfusion seen on the OCTA density map in both eyes. Six months after specific SuS therapy, retinal vascular perfusion showed partial improvement in both eyes.ConclusionOCTA may demonstrate superficial and deep retinal vascular non-perfusion without choriocapillary vasculature changes in SuS. This anatomical information given by OCTA corresponded to points of low sensitivity on functional tests represented by VF and MP.

Widefield OCT angiography and ultra-widefield multimodal imaging of Susac syndrome

“…Some cases of SuS analyzed by means of multimodal WF imaging 5 and OCTA [6][7][8] have been reported, but this is the first report of SuS imaged by means of WF OCTA and for an intermediate long follow-up.…”

“…4 In our case, areas of capillary non-perfusion were better outlined by WF OCTA rather than FA due to the absence of leakage and choroidal background fluorescence. Some cases of SuS analyzed by means of multimodal WF imaging 5 and OCTA [6][7][8] have been reported, but this is the first report of SuS imaged by means of WF OCTA and for an intermediate long follow-up.…”

Susac’s syndrome – the crucial role of imaging tests for proper diagnosis

“…Recently, single reports have been published concerning changes in OCTA in patients with SS. These studies demonstrated an unaffected choriocapillaris vasculature and both superficial and deep retinal vascular plexuses damage characterized by vascular non-perfusion, which corresponds to the topography of BRAO [30,31]. Todorich et al described a case of SS with BRAO, where typical for BRAO hyperreflectivity of the inner and middle retinal layers was observed, characteristic of acute ischaemia [32].…”

“…The researchers hypothesized that a change in vascular flow associated with the activity of the disease was responsible for these changes. Inflammation of the vascular vessels may lead to a lower vascular flow due to the narrowing of the vessel [31]. Mastropasqua et al described a case of SS, where after the application of treatment, OCTA images also disclosed an increase in VD [69].…”

“…The wide range of imaging techniques currently available, such as brain MRI, fluorescein angiography (FA), optical coherence tomography (OCT), and OCT angiography (OCTA), allow the recognition of anatomical and physiological correlations underlying the pathology of SS [2,[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. MRI and FA both enable the imaging of pathognomonic changes for SS [2].…”