One continuous way from CT to C0 in the Mimics Innovation Suite

Ever attempted to get solid CAD data out of medical imaging data? Impossible? No, but very complex and time-consuming at least. Until now…

Medical imaging data, like CT or MRI, can be segmented to create accurate, patient-realistic, 3D models. However, these complex, organic 3D models are generated in the STL file format, and this format is not welcomed by traditional CAD softwares. Most of them can import these anatomical STL files, but then you can’t perform design operations. That’s why, several years ago already, Materialise developed 3-matic; to perform design operations directly on anatomical geometries, allowing the design of patient-specific implants or surgical guides. This technology, dubbed ‘ anatomical CAD’ is at the basis of mass personalization in the orthopedic and CMF markets.

Still, there is a need to get accurate anatomical data into CAD. Therefore, Materialise developed a new module for 3-matic: Anatomical Reverse Engineering. This module can create solid (C0-continuity) IGES files from anatomical models and it does so completely automatic.

“The combination of medical image segmentation in Mimics with the ability to do reverse engineering on anatomical geometries, is highly desired by medical device companies. It allows them to improve their implants by using patient-realistic data in their CAD environment.”

Koen Engelborghs – Director Biomedical Engineering

How does it work?

The Mimics Innovation Suite enables the following workflow:

First use Mimics to segment (1) DICOM data and create (2) an accurate 3D model of selected anatomy. This 3D first needs some defeaturing before it can be converted to IGES. Wrapping is the tool of choice here, maybe in combination with some smoothing, to get to (3) a smooth 3D model. Now choose IGES export in 3-matic, define a patch density and save your patient-realistic IGES file directly to disk, ready to be opened in any CAD package.

How long does it take?

E.g. on a vertebral body it takes only approximately 30 seconds to create the IGES file from the smooth 3D model. (The smooth model containing almost 38,000 triangles; the resulting IGES file consisting of 646 faces.) Since wrapping and smoothing are also done in seconds, segmentation is the most time-consuming step in the process. Fortunately Mimics is the fastest and easiest software available to do that. Depending on the segmentation skill and the quality of the DICOM images, the average user should be able to complete the above workflow within 30 minutes. A skilled user working on ideal image data would be able to do this within 5 minutes.

Is it accurate?

Very accurate. In the case of the vertebra here, a part comparison analysis reveals that 96% of the surface of the IGES file is within ±0.03 mm of the smooth anatomical model. The maximum deviation is only 0.15mm.

Interested in reverse engineering of anatomical data, contact Materialise at Email Contact