Retinal imaging including optical coherence tomography angiography for detecting active choroidal neovascularization in pseudoxanthoma elasticum

Importance: The diagnostic accuracy of different retinal imaging modalities to detect active choroidal neovascularization (CNV) in pseudoxanthoma elasticum (PXE) is essential to enable a correct diagnosis but is currently poorly understood.

Background: Optical coherence tomography (OCT), fluorescein angiography (FA) and OCT angiography (OCT-A) are employed in daily practice, but a systematic comparison of these imaging techniques is lacking.

Design: Retrospective, observational study.

Participants: Twenty patients (31 eyes) with PXE.

Methods: OCT, FA and OCT-A imaging was performed in each eye and graded separately by independent readers.

Main outcome measures: Diagnostic accuracy, sensitivity and specificity to detect CNV-activity of each modality and longitudinal change of CNV size measured by OCT-A.

Results: OCT showed the highest diagnostic accuracy (kappa = 0.57) in comparison to OCT-A or FA (kappa = 0.39 and 0.37, respectively). OCT-A, OCT and FA showed a diagnostic sensitivity of 0.9, 0.85 and 0.6, and a diagnostic specificity of 0.45, 0.72 and 0.82, respectively. Evaluation of longitudinal OCT recordings (24 eyes) resulted in optimal sensitivity and specificity (kappa = 1.0). Although median CNV size assessed using OCT-A remained stable on longitudinal measures of seven eyes, two eyes showed a distinct increase over time despite anti-vascular endothelial growth factor treatment.

Conclusions and relevance: The systematic use of OCT, FA and OCT-A imaging can facilitate the diagnostic accuracy for detection and follow-up of CNV activity in PXE. While structural OCT is of high value, especially when longitudinal follow-up images are available, FA and OCT-A data might contribute to diagnostic accuracy in more complex cases.