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.
Cerebral edema is a serious complication of ischemic cerebrovascular disease and mannitol is a commonly used dehydrating agent for relieving cerebral edema. However, the edema state and surrounding vascular perfusion level during mannitol treatment remains unclear, which affects the clinical application of the medicine. In this paper, we demonstrated the role of swept-source optical coherence tomography (OCT) in the evaluation of mannitol efficacy using mouse models. The OCT-based angiography and attenuation imaging technology were used to obtain the cerebral vascular perfusion level and cerebral edema state at different times. Vascular parameters and edema parameters were quantified and compared. Experimental results show that mannitol can significantly reduce the water content in the central region of edema, effectively inhibiting the rapid growth of the edema area, and restoring cerebral blood flow. On average, the edema area decreased by 33% after 2 h, and the vascular perfusion density increased by 12% after 5 h. This work helps to provide a valuable theoretical basis and research ideas for the clinical treatment of cerebral edema.
We propose a high-speed all-optic dual-modal system that integrates spectral-domain optical coherence tomography and photoacoustic microscopy (PAM). A [Formula: see text] coupler-based interferometer is used to remotely detect the surface vibration caused by photoacoustic (PA) waves. Three outputs of the interferometer are acquired simultaneously with a multi-channel data acquisition card. One channel data with the highest PA signal detection sensitivity is selected for sensitivity compensation. Experiment on the phantom demonstrates that the proposed method can successfully compensate for the loss of intensity caused by sensitivity variation. The imaging speed of the PAM is improved compared to our previous system. The total time to image a sample with [Formula: see text] pixels is [Formula: see text][Formula: see text]s. Using the proposed system, the microvasculature in the mouse auricle is visualized and the blood flow state is accessed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.