Toward Intraoperative Brain-Shift Detection Through Microwave Imaging System.

This work shows a proof of concept of a radar-based microwave imaging (MWI) system for the detection of the brain-shift effect with minimum delay. The system is based on the estimation of the variations of both the position and the geometry of the brain in order to detect if remarkable variations have occurred. To that end, the system makes use of 12 twin antennas as sensing elements, which transmit broadband signals toward the patient's head and receive the corresponding reflections. Printed monopole antennas with coplanar feed are considered, featuring a broad bandwidth and an omnidirectional radiation pattern. A signal processing strategy to estimate the detected distances to the target from the reflection seen by each antenna is also shown, as well as a calibration and fine-tuning procedure for accurate distance detection capabilities. To demonstrate the potential of the system, a cranium phantom and several brain phantoms, emulating different brain-shift cases, are fabricated and measured. The results show the effective detection of the brain-shift in all the cases under consideration, thereby demonstrating the potential of MWI systems for effective intraoperative brain-shift detection.