Velocity Model-Based Aberration Correction and Transcranial Ultrasound Localization Microscopy in the Rat Brain

Transcranial ultrasound localization microscopy is a non-invasive technique for imaging the cerebral vasculature. However, the presence of the cranial bone introduces challenges to transcranial ULM, including the attenuation of acoustic waves, and phase aberration. In this study, a velocity model-based aberration correction method is proposed, which can recalculate the correct traveltime by solving the Eikonal equation based on an existing velocity model. The validity of this methods is substantiated through in vivo experiments in rat brains. Results show that the velocity model-based aberration correction enables a spatial resolution improvement of about 3.1 μm and an imaging saturation enhancement of 3% on average, revealing the vessels down to 31.9 μm in diameter. This study suggests that velocity model-based aberration correction has the potential for the application in the transcranial imaging, and the transcranial ULM is a promising microvascular imaging method.