  Purpose: Image guidance is crucial for the success of many interventions.
Images are displayed on designated monitors that cannot be positioned optimally
due to sterility and spatial constraints. This indirect visualization causes
potential occlusion, hinders hand-eye coordination, leads to increased
procedure duration and surgeon load. Methods: We propose a virtual monitor
system that displays medical images in a mixed reality visualization using
optical see-through head-mounted displays. The system streams high-resolution
medical images from any modality to the head-mounted display in real-time that
are blended with the surgical site. It allows for mixed reality visualization
of images in head-, world-, or body-anchored mode and can thus be adapted to
specific procedural needs. Results: For typical image sizes, the proposed
system exhibits an average end-to-end delay and refresh rate of 214 +- 30 ms
and 41:4 +- 32:0 Hz, respectively. Conclusions: The proposed virtual monitor
system is capable of real-time mixed reality visualization of medical images.
In future, we seek to conduct first pre-clinical studies to quantitatively
assess the impact of the system on standard image guided procedures.
