A Novel Quantitative Assessment Method of Disease Activity in Susac’s Syndrome Based on Ultra-Wide Field Imaging

ABSTRACT

Purpose

Susac’s syndrome (ScS) is a rare, potentially life-threatening auto-immune disease. Ophthalmic imaging can depict characteristic branch retinal arteriolar occlusions (BRAO) and arterial wall hyperfluorescences that form one of the three diagnostic pillars of this condition. We aim to demonstrate that ophthalmological ultrawide-field (UWF) imaging allows for a qualitative and quantitative assessment in ScS, with application in diagnostics, monitoring of treatment response, and titration of therapy.

Methods

In seven ScS patients (♀:♂ = 2:5), with a median age of 36 years, range 18 to 57 years, serial ultrawide-field fluoresceine angiography (UWF-FA) studies were performed, with adjunctive wide-field optical coherence tomography angiography analyses (WF-OCTA) in five patients. Mean follow-up was 12.5 months, range 1 to 46 months.

Results

In all seven patients, BRAO and arterial wall hyperfluorescences were present in UWF-FA and calculated as a quantitative score of disease activity in fluorescein angiography (DA-FA) during follow-up visits. Treatment response was accessible in follow-up imaging as partial reperfusion of retinal vessels, resolution of arterial wall hyperfluorescences and consequently, in reduction of DA-FA score. While qualitative analysis of WF-OCTA provided further information about retinal micro-perfusion, quantitative analysis did not demonstrate a vectored treatment response as it was accessible in FA.

Conclusion

DA-FA score, as a comprehensive disease activity parameter in ScS has potential to facilitate optimal communication between subspecialties and thereby treatment success.

KEYWORDS:

• Susac’s syndrome (ScS)
• ultrawide-field fluoresceine angiography (UWF-FA)
• wide-field optical coherence tomography angiography analyses (WF-OCTA)
• quantitative analysis
• branch retinal arteriolar occlusions (BRAO)

Acknowledgments

Financing of this study was acquired through an unrestricted research grant provided by Novartis Pharma Schweiz AG.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethical approval

Institutional review board approval was obtained (trail registration number: BASEC202002481) by local ethics committee Zurich, Zurich, Switzerland. All patients provided informed consent to publish their clinical data. The study was conducted in accordance with the principles of the declaration of Helsinki.

Author contributions

Sandrine Zweifel, Timothy Hamann, Maximilian Wiest, Will Innes contributed to the study conception and design. Material preparation, data collection and analysis were performed by all authors. The first draft of the manuscript was written by Timothy Hamann and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Additional information

Funding

This work was supported by the Novartis Pharma CH AG (unrestricted research grant).