Optical coherence tomography‐based determination of ischaemia onset – the temporal dynamics of retinal thickness increase in acute central retinal artery occlusion

Abstract

Purpose Acute central retinal artery occlusion (CRAO) induces ischaemic retinal oedema. The purpose of this study was to define sensitivity and specificity of optical coherence tomography (OCT) based retinal thickness analysis in determining ischaemia onset in CRAO. Methods The relative retinal thickness increase (RRTI) in comparison with the fellow eye was analysed retrospectively in OCT scans of 66 patients diagnosed with CRAO between January 2010 and December 2019 within 48 hr of ischaemia onset. The natural course of RRTI and the sensitivity and specificity of OCT‐based determination of ischaemia onset in identifying CRAO within 4.5 hr using the RRTI were evaluated. Results Relative retinal thickness increase (RRTI) in acute CRAO follows a hyperbolic curve with a steep incline within the early phase after which it reaches a plateau. Optical coherence tomography (OCT)‐based retinal thickness analysis in CRAO allows to differentiate patients with ischaemia onset within the past 4.5 hr or thereafter with a sensitivity of 100% and a specificity of 94.3%. Conclusion Relative retinal thickness increase (RRTI) allows to identify CRAO patients that are eligible for a potentially beneficial reperfusion therapy within a therapeutic window of 4.5 hr with a high accuracy. Especially in patients with unknown ischaemia onset, this diagnostic tool could be of major importance in the future clinical management.

Determination of Ischemia Onset Based on Automatically Generated Spectralis SD-OCT Values in Acute Central Retinal Artery Occlusion

“…In all sectors, TTO and RRTI correlated positively. Figure 1 displays this exemplary for the nasal sector over the full time frame of 48 hours for both the manual [ 5 ] as well as the automatic measurements. The RRTI calculated with either measurement tool (manual or automated, p = 0.8372) follows a hyperbolic curve with a steep incline in the first 10 hours and then reaching a plateau.…”

“…In previous studies, we presented the temporal changes of retinal thickness in acute CRAO patients [ 5 , 16 ]. We showed with a sensitivity of 100% and a specificity of 94.3% that RRTI is a valuable surrogate parameter to determine if ischemia onset was within the last 4.5 hours [ 5 ].…”

“…In previous studies, we presented the temporal changes of retinal thickness in acute CRAO patients [ 5 , 16 ]. We showed with a sensitivity of 100% and a specificity of 94.3% that RRTI is a valuable surrogate parameter to determine if ischemia onset was within the last 4.5 hours [ 5 ]. In our previous publication, the total retinal thickness was measured manually at the thickest point between the optic nerve and fovea, and this measurement was always performed perpendicular to the retinal pigment epithelium (RPE).…”

“…The RRTI is the increase in retinal thickness of the affected eye compared to the unaffected eye in percent. Manual measurement of the retinal thickness was performed like previously described [ 5 ]. In brief, the thickest point of the retina in the papillomacular bundle was manually measured with the virtual ruler tool of Heidelberg Eye Explorer software.…”

“…In a previous study [ 5 ], we have shown that, in CRAO patients, ischemia onset ≤4.5 hours can be determined by manual measurement with a sensitivity of 100% and a specificity of 94.3%. This manual analysis of optical coherence tomography (OCT) scans is based on the relative retinal thickness increase (RRTI) in comparison to the fellow eye.…”