Characterization of Macular Structural and Microvascular Changes in Thalamic Infarction Patients: A Swept-Source Optical Coherence Tomography–Angiography Study

Abstract

Background: The retina and brain share similar neuronal and microvascular features. We aimed to investigate the retinal thickness and microvasculature in patients with thalamic infarcts compared with control participants. Material and methods: Swept-source optical coherence tomography (SS-OCT) was used to image the macular thickness (retinal nerve fiber layer, RNFL; ganglion cell-inner plexiform layer, GCIP), while OCT angiography was used to image the microvasculature (superficial vascular plexus, SVP; intermediate capillary plexus, ICP; deep capillary plexus, DCP). Inbuilt software was used to measure the macular thickness (µm) and microvascular density (%). Lesion volumes were quantitively assessed based on structural magnetic resonance images. Results: A total of 35 patients with unilateral thalamic infarction and 31 age–sex-matched controls were enrolled. Compared with control participants, thalamic infarction patients showed a significantly thinner thickness of RNFL (p < 0.01) and GCIP (p = 0.02), and a lower density of SVP (p = 0.001) and ICP (p = 0.022). In the group of patients, ipsilateral eyes showed significant reductions in SVP (p = 0.033), RNFL (p = 0.01) and GCIP (p = 0.043). When divided into three groups based on disease duration (<1 month, 1–6 months, and >6 months), no significant differences were found among these groups. After adjusting for confounders, SVP, ICP, DCP, RNFL, and GCIP were significantly correlated with lesion volume in patients. Conclusions: Thalamic infarction patients showed significant macular structure and microvasculature changes. Lesion size was significantly correlated with these alterations. These findings may be useful for further research into the clinical utility of retinal imaging in stroke patients, especially those with damage to the visual pathway.

Alterations of optic tract and retinal structure in patients after thalamic stroke

“…Our current report builds upon our previous report on retinal neurodegeneration following thalamic infarction (Ye et al, 2022) and the fundamental observations that such retrograde transsynaptic neurodegeneration after visual pathway insult follows a distinct time course and pattern (Jindahra et al, 2012;Saionz et al, 2020;Fahrenthold et al, 2021). This study showed that the LI value, which indicates the shrinkage extent of the optic tract (Bridge et al, 2011;Millington et al, 2014;Fahrenthold et al, 2021), altered distinctly compared with age-sex matched stroke-free controls.…”

“…Previous reports showed that transsynaptic retrograde neurodegeneration (TRD) after post-thalamic visual area (occipital lobe) stroke was high after the first few years and fairly stable over the years ( Cowey et al, 2011 ; Jindahra et al, 2012 ; Meier et al, 2015 ; Schneider et al, 2019 ). In our previous report ( Ye et al, 2022 ), thalamic infarction patients with a duration of more than 6 months also showed a thinner retinal structure compared to patients with a duration of fewer than 6 months. These findings suggest that retinal degeneration follows a clear-cut time sequence, i.e., retrograde degeneration is progressive and becomes steady over time.…”

“…It is suggested that the retina can act as a novel and non-invasive imaging marker with potential diagnostic and clinical significance in neurological diseases (Cabrera DeBuc et al, 2017;Mutlu et al, 2017;Kwapong et al, 2018). Thinning of the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL)-inner plexiform layer (GCIPL) has been consistently documented in previous reports (Park et al, 2013;Zhang et al, 2020;Kashani et al, 2021;Snyder et al, 2021;Ye et al, 2022) in most cerebrovascular disorders. These reports suggest retinal neurodegeneration reflects cerebral neurodegeneration, and this mechanism may occur simultaneously.…”

“…Swept-source optical coherence tomography (SS-OCT, VG 200, SVision Imaging Limited, Luoyang, China) was used to image the structure of the retina by an experienced neuro-ophthalmologist (WK). The specifications of the OCT tool have been well described in our previous report ( Ye et al, 2022 ). As shown in Figure 2 , the peripapillary retinal nerve fiber layer (pRNFL) was done using the optic nerve head protocol with a scanning range covering a circle with a diameter of 3.45 mm focused on the optic disc.…”

Linked Distinct Multi-modular Brain Connectivity Patterns with Retina Microvascular and Structural Alterations, and Their Correlations with Visual Performance in Thalamic Stroke

“…Owing to its connection with the thalamus and the fact that it can be non-invasively visualized, the retina is suggested to provide important information on brain pathology [18,19]; and we assume that it could be a future target of imaging in thalamic stroke. Indeed, our previous reports have shown thalamic stroke patients have thinner retinal structures and reduced microvascular densities compared to age-and-sexmatched healthy controls [20,21]; importantly, we further showed alterations of structural changes around the optic nerve head and retina in thalamic stroke patients were related to shrinkage of the optic tract, and all these changes were correlated with visual perfomence [20].…”