Artikel
Spreading depolarisations can be detected by photoacoustic ultrasonic imaging in the deep gyrencephalic swine brain
Spreading Depolarizations können durch photoakustische Ultraschallbildgebung im tiefen gyrencephalen Schweinehirn nachgewiesen werden
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Veröffentlicht: | 25. Mai 2022 |
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Objective: Spreading depolarizations (SDs) are associated with poor neurological outcomes in cerebrovascular diseases and brain trauma. Until now, the standard method to measure SDs in patients is by using electrocorticography (ECoG). There are other techniques such as laser doppler, laser speckle and intrinsic optical imaging. However, they all provide few information on SD beyond the surface. The aim of this study was to investigate if SDs can be detected by using photoacoustic ultrasonic (PAUS) imaging in the gyrencephalic swine brain and if SDs can be detected on deep cortical tissue.
Methods: A German landrace swine were used for this study. An extensive craniotomy was performed. ECoG recording strip was placed on both hemispheres. SDs were induced with a drop of KCl. After a 10min baseline, a stimulation was performed, with 30min recording after application. Stimulations were performed every 40min. A total of 5 stimulations per hemisphere were performed. Animals were monitored with PAUS for 3.5h.
Results: By offline estimation of the sO2, in each pixel of the reconstructed multispectral images, SDs were visualized as sO2changes propagating from the stimulation point though different ROIs. Estimated sO2 changes presented a good correlation with SD detected in ECoG. In PAUS a total of 18 SDs were detected during the monitoring time Figure 1 [Fig. 1]. SDs were detected up to 4mm depth. No apparent anatomical dependency was found in relationship to depth. The most predominant responses (21 ROI measurements) were a biphasic change of initial decrease plus increase of sO2 (14%); and a triphasic change of of initial decrease plus increase and decrease of sO2 (14%).
Conclusion: We conclude that PAUS can image SDs with a high resolution and high imaging depth in the gyrencephalic swine brain.