3D printing in MRI-compatible plastic resin has been used to fabricate and implement a geometric distortion phantom for MRI and CT imaging. The sparse grid structure provides a rigid and accurate phantom with identifiable intersections that are larger than the supporting members, which produces images that are amenable to fully automated quantitative analysis using morphometric erosion, greyscale segmentation and centroiding. This approach produces a 3D vector map of geometric distortion that is useful in clinical applications where geometric accuracy is important, either in routine quality assurance or as a component of distortion correction utilities.
Method and apparatus for measuring 3D geometric distortion in MRI and CT images with a 3D physical phantom