Skull Phase Compensation Combined Full Waveform Inversion for Transcranial Thermoacoustic Imaging With a Real Human Skull Validated

In recent years, cerebrovascular disease has become one of the leading causes of death among Chinese residents. Early detection of brain disease is, therefore, of great significance in reducing the risks to life and health. Thermoacoustic imaging has emerged as a promising technique for detecting brain disease, which meets the requirements of high penetration depth and real-time imaging in transcranial imaging. However, the acoustic characteristics of the skull can significantly impact the propagation of thermoacoustic signals, leading to attenuation and apparent phase difference, resulting in poor quality of reconstructed image and location deviation of symptom points. In this study, a skull phase compensated method combined full waveform inversion for transcranial thermoacoustic imaging is proposed. The adaptive positioning of skull is realized firstly by improving the W-AIC algorithm in thermoacoustic imaging to solve the phase difference problem and FWI technology is applied for reconstructing the intracranial SoS distribution. Numerical simulation of a human brain model and actual human skull experiments further verify the feasibility of this method in improving the quality of thermoacoustic images, thereby providing a reliable theoretical basis for the clinical application of transcranial thermoacoustic imaging.