B-mode and Doppler imaging of in vivo rat brain and ex vivo human brain with a high frequency endoscopic phased array

摘要

A high frequency ultrasound endoscope could find applications in many fields of surgery and diagnostics. Our group has been developing phased array endoscopes in the 30-45 MHz range, along with beamforming hardware for high resolution imaging, with a focus on neurosurgical applications. In this study, we imaged in vivo anesthetized rat brains and ex vivo human brain samples in order to characterize brain tissue appearance. A simple blood flow imaging method was also used in vivo to view some of the vasculature. Imaged brain tissue was sectioned and stained for comparison with the ultrasound images. In vivo, we found that the fluid-filled ventricles and boundaries between adjacent tissue regions separated by fissures were the most distinct features. Other brain substructures were also visible, such as the granular cell layers of hippocampus, caudate putamen, and cerebellar layers. In rats, gray matter and white matter did not appear as different as expected. However, in human brain samples the cerebral gray/white matter distinction was more obvious.