  Since the invention of modern CT systems, metal artifacts have been a
persistent problem. Due to increased scattering, amplified noise, and
insufficient data collection, it is more difficult to suppress metal artifacts
in cone-beam CT, limiting its use in human- and robot-assisted spine surgeries
where metallic guidewires and screws are commonly used. In this paper, we
demonstrate that conventional image-domain segmentation-based MAR methods are
unable to eliminate metal artifacts for intraoperative CBCT images with
guidewires. To solve this problem, we present a fine-grained projection-domain
segmentation-based MAR method termed PDS-MAR, in which metal traces are
augmented and segmented in the projection domain before being inpainted using
triangular interpolation. In addition, a metal reconstruction phase is proposed
to restore metal areas in the image domain. The digital phantom study and real
CBCT data study demonstrate that the proposed algorithm achieves significantly
better artifact suppression than other comparing methods and has the potential
to advance the use of intraoperative CBCT imaging in clinical spine surgeries.
