  Ultrasound (US) imaging provides a safe and accessible solution to procedural
guidance and diagnostic imaging. The effective usage of conventional 2D US for
interventional guidance requires extensive experience to project the image
plane onto the patient, and the interpretation of images in diagnostics suffers
from high intra- and inter-user variability. 3D US reconstruction allows for
more consistent diagnosis and interpretation, but existing solutions are
limited in terms of equipment and applicability in real-time navigation. To
address these issues, we propose HoloPOCUS - a mixed reality US system (MR-US)
that overlays rich US information onto the user's vision in a point-of-care
setting. HoloPOCUS extends existing MR-US methods beyond placing a US plane in
the user's vision to include a 3D reconstruction and projection that can aid in
procedural guidance using conventional probes. We validated a tracking pipeline
that demonstrates higher accuracy compared to existing MR-US works.
Furthermore, user studies conducted via a phantom task showed significant
improvements in navigation duration when using our proposed methods.
