MR Image Overlay: an Augmented Reality System for Needle Guidance

Abstract

MRI-guided percutaneous needle-based surgery has become part of routine clinical practice. There are millions of these procedures performed in Canada. The conventional MRI-guided needle intervention is usually performed with the primary goal of navigating a needle to a target while sparing healthy and/or critical structures. Potential limitations of conventional unassisted free-hand needle placement include the physician's ability to align and maintain the correct trajectory and angle toward a target, especially in case of deep targets. In contemporary practice, images are displayed on the operator's 2D console only outside the treatment room, where the physician plans the intervention. Then the physician enters the room, mentally registers the images with the anatomy of the actual patient, and uses hand-eye coordination to execute the planned intervention. Previous concept has been shown and preliminary results discussed from demonstrated MRI-guided needle intervention using an augmented reality 2D image overlay system in a closed configuration 1.5T MRI scanner. However, the limited availability of interventional MR imaging systems and the length of time of MR-guided interventions have been limiting factors in the past. This dissertation addresses topics related to evaluating and developing the 2D augmented reality system, the assistance device for MRI-guided needle interventions. This research effort has primarily focused on developing a new adjustable 2D MR image overlay system and validating the previous 2D image overlay system in the clinical environment. The adjustable system requirement is to overcome the oblique insertions, difficulties inherent to MR-guided procedures, and to promise safe and reliable needle placement inside closed high-field MRI scanners. This thesis describes development of the image overlay system including requirements, mechanism design and evaluation of MR compatibility. Additionally, a standalone realization of an MR image overlay system, named “The Perk Station” was developed, implemented and evaluated. The system was deployed in the laboratory as a training/teaching tool with non-bio-hazardous specimens. This laboratory version of the system allows for evaluation of trial interventions. The system also supports recording of the complete intervention trajectory for operator performance, technical efficacy, and accuracy studies of insertion techniques.