Monitoring of edema progression in permanent and transient MCAO model using SS-OCT

Abstract

Cerebral edema is a severe complication of acute ischemic stroke with high mortality but limited treatment. Although parameters such as brain water content and intracranial pressure may represent the global assessment of edema, optical properties can appear heterogeneously throughout the cerebral tissue relative to the site of injury. In this study, we have monitored the edema formation and progression in both permanent and transient middle cerebral artery occlusion models in rats. Edema was reflected by the decrease of optical attenuation coefficient (OAC) value in OCT system. By utilizing swept-source optical coherence tomography (SS-OCT), we found that in photochemically induced permanent focal stroke model, both the edema size and edema index, steadily developed until the end of monitor (7[Formula: see text]h). Comparatively, when transient ischemia was introduced with endothelin-1 (ET-1), the edema was detected as early as 15[Formula: see text]min, and began to recover after 30[Formula: see text]min until monitor was finished (3[Formula: see text]h). Despite the majority of the edema being recovered to some extent, the condition of a small region within the edema kept deteriorating, presumably due to the reperfusion damage which might result in serious clinical outcomes. Our study has compared the edema characteristics from two different acute ischemic stroke situations. This work not only confirms the capability of OCT to temporal and spatial monitor of edema but is also able to locate focal conditions at some areas that might highly determine the prognosis and treatment decisions.

In vivo characterization of cerebrovascular impairment induced by amyloid β peptide overload in glymphatic clearance system using swept-source optical coherence tomography

“…This makes OAC a competent parameter to distinguish edema tissue from normal tissue. 45 , 90 We found that OAC value reduced uniformly throughout the brain, indicating a global edema condition, coincided with the vasogenic edema observed with MRI hyperintensities in ARIA. 12 , 92 …”

“… 89 We have also successfully utilized it to assess the water content and cerebral edema resulted from cerebral infarction. 45 , 90 In this study, the average OAC value of brain tissue decreased dramatically over time after ventricular injection of ( Fig. 8 ).…”

Evaluation of Mannitol Intervention Effects on Ischemic Cerebral Edema in Mice Using Swept Source Optical Coherence Tomography

“…Optical coherence tomography (OCT), which reconstructs depth information images of biological tissues using backscattered light from the sample, has the advantages of non-contact, non-invasive and a high resolution [21]. OCT technology appeared in the 1990s and gradually transited to frequency domain OCT from time domain OCT [22].…”