UCSF

Objective: The primary objective of this study is to investigate the performance of augmented reality (AR) in representing and displaying 3D holographic models derived from 3D MR acquisitions. In addition, the existing picture archiving and communication system (PACS) will be examined as well.

Methods: A compatible phantom model for the 3.0T standard bore GE MRI scanner was used and fiducial markers set at various known distances were placed on the surface of the model. The distances were measured using a digital caliper, establishing the reference gold standard. Five separate configurations were created using the same phantom model by rearranging the fiducial markers. A set of six total measurements between fiducial markers were made in each configuration: two along the x-direction, two along the y-direction, and two along the z-direction. Four different 3D MR sequences were implemented to scan each configuration. The resulting 3D MR images of each sequence for every configuration were stored as digital imaging and communications in medicine (DICOM) files and sent to PACS. The corresponding six distances were then measured using the built-in PACS ruler tool. Open-source 3D rendering software programs were used to translate the DICOM files into 3D models, which were then loaded onto an AR platform. The 3D models were displayed as holograms and the overlaid distances between the fiducial markers were measured using a physical digital caliper. Since the assumptions for parametric statistical analysis were violated, the nonparametric statistical method was adopted to examine the statistical differences among the three groups (gold standard, PACS, and AR).

Results: The results showed no statistically significant difference between AR measurements and gold standard measurements (p = 0.6208). However, a statistically significant difference between PACS measurements and gold standard measurements (p = 0.0118) was present.

Conclusion: Distance measurements in AR models derived from MRI scans show no statistically significant difference compared to gold standard measurements. AR can be used to accurately measure distance for surgical planning and clinical use.