DICOM International Conference & Seminar Work Item Implants – Current State and Outlook Michael Gessat Thomas Trommer, Armin Löpfe, Oliver Burgert

2 Outline  Implant Templates and Implantation Planning  Motivation  Features  Information Models  Examples

3 Implant Templates & Implantation Planning  The pre-operative selection of the most suitable implant and the determination of the optimal position and fixation of an implant in the patient’s body is called implantation planning.  Planning is done with radiological images and graphical representations of implants, called implant templates.

4 Implant Templates & Implantation Planning

5 Motivation PACS Server Vendor Template Repository Planning Workstation Patient Images Implant Templates Planning Report Required Templates Intraoperative System Patient Images HIS EHR Data  At present:  No standardized semantics and syntax for implant templates  No standardized format for planning results  No integration of information flow into PACS

6 Motivation Patient Images Implant Templates Planning Report Required Templates Intraoperative System Patient Images HIS EHR Data Planning Report Required Templates PACS Server incl. Temp. Rep. Planning Workstation  Our goal:  Implant templates standardized in DICOM  Implantation plans standardizes in DICOM  All data stored in PACS server  Whole data is exchanged via PACS

7 Required Concepts  Patient‘s Morphology  X-Rays, CTs, 3D Ultrasound  Segmentation and Classification  Implant Geometry  2D  3D  Result Simulation  Biomechanical properties  Tissue deformation  Transfer into the OR  Network technology & Displays  Transfer protocols and formats

8 DICOM Sup. 131 and 134 Bone Mounted Implants ImplantsImplants Stents, Valves, …Many more HipShoulderDentalSpine Middle Ear Implant Repository: Implant Repository: Bone Mounted Implant Template Storage SOP Class Patient Specific Plan / Report: Patient Specific Plan / Report: Implantation Plan Document SOP Class General Surface Mesh Module Encapsulated HPGL 2 Based on SR

9 Workshops  In workshops with representatives from the implant industry and implantation planning software industry.  Leipzig, December 13, 2007  San Francisco, March 3, 2008  A set of features and attributes was elaborated.  Working Group 24 is working on the translation of the workshop results into DICOM Supplements.  In parallel, ICCAS works on a test implementation of the new DICOM SOP Classes.

10 Features  Implant Templates  contain 2D and/or 3D representation,  contain (anatomical) landmarks for registration with patient images,  contain information about indication, and  can consist of several components,  Component assembly is described: compatibility, geometric constraints, and degrees of freedom.

11 Information Model - Implant Templates Implant Component 1 1-n Surface Model Fiducial Manufacturer Frame of Reference 11-n n Contact 0-n1-n accepts has spatially defines produces consists of 1 0-n D Template has 1 0-n

12 Example Component 1 “Hip Joint Head” “Material: Porcelain” Contact 1 Coordinates Axes Link: Comp. 2, CP 1 Component 2 “Hip Joint Shaft” “Material: Titan” Contact 1 Coordinates Axes Link: Comp. 1, CP 1 Fiducial 1 Femur Axis

13 Implant Types  Implants for different purposes differ very much in the Attributes and landmarks that describe them.  We propose an encoding mechanism that leaves room for a lot of flexibility.  Only the Attributes that are applicable to the type of implant that is described in one Instance need to be present. General Implant Attributes Hip Joint Assembly Dental Implant

14 Implantation Plan SR Document: Features Registration Templates (Implant Components) Patient ImageVisualization Anatomical Fiducials Implantation Plan Assembly description Planning Information Derived Fiducials Images: ENDOTEC

15 Information Model - Implantation Plan SR Document Implant IOD Surface ModelFiducials Implantation Plan SR contains references Registration IOD Image IOD Surface Seg. IOD Spatial Fiducials IOD refers to spatially aligns 2D Templates

Acknowledgements The Innovation Center Computer Assisted Surgery (ICCAS) at the Faculty of Medicine at the University of Leipzig is funded by the German Federal Ministry for Education and Research (BMBF) and the Saxon Ministry of Science and the Fine Arts (SMWK) in the scope of the initiative “Unternehmen Region” with the grant numbers 03 ZIK 031 and 03 ZIK 032. Gefördert im Rahmen der Technologieförderung mit Mitteln des Europäischen Fonds für regionale Entwicklung (EFRE) und mit Mitteln des Freistaates Sachsen. Thank you very much for your attention!