Phase jolt: Second spatial derivative of phase images is a new contrast that offers many benefits for SWI type processing

Motivation: Unlike magnitude images, even simple averaging is difficult with phase images, because of the circular nature of phase, spanning 2pi radians range. Goal(s): In our research that uses mesoscopic imaging (< 0.5 mm isotropic) at 7 T, we need to average multiple acquisitions to increase SNR. Being unable to average straightforwardly together with the lack of natural zero point is a critical constraint. Approach: To address this problem, we propose to operate on the magnitude of the second spatial derivative of phase images - called “phase jolt”. Results: Our results show phase jolt offers benefits for processing associated with SWI imaging. Impact: Phase jolt is an easy to implement new contrast where vessels and non brain tissue are highlighted and background bias field is mitigated. Therefore, phase jolt images have potential to be impactful in any setting where phase images are used.