Program Information
Head Imaging with C-Arm CT: Investigation On the Impact of Data Redundancy Handling and Orientation of the Scanning Plane On Image Quality
Z Guo1*, G Lauritsch2 , A Maier3 , F Noo4 , (1) University of Utah, Salt Lake City, UT, (2) Siemens Healthcare GmbH, Forchheim, Germany, (3) University of Erlangen-Nuremberg, Erlangen, Germany, (4) University of Utah, Salt Lake City, UT
Presentations
TH-AB-601-5 (Thursday, August 3, 2017) 7:30 AM - 9:30 AM Room: 601
Purpose: We are interested in assessing if image quality in C-arm CT imaging of the head can be improved using two features. The first feature is a change in the orientation of the scanning plane to emulate the gantry-tilt geometry used in diagnostic CT. The second feature is the utilization of a reconstruction algorithm that properly accounts for data redundancy, unlike the short-scan FDK algorithm (SS-FDK).
Methods: An anthropomorphic phantom of the head was scanned with an Artis Zeego system (Siemens Healthcare GmbH, Forchheim, Germany). The phantom was placed on a foam pad to simulate scanning with a geometry equivalent to that of a gantry tilt. Two tilt angles were considered, 10 and 20 degrees, to be compared to the geometry with no tilt. Reconstruction for the three scans was performed with SS-FDK, as well as another filtered-back-projection method (ACE) that correctly accounts for data redundancy using the 3D Radon transform and Grangeat’s formula. Comparison between reconstructions without and with tilt was enabled using volume registration. Reconstructed volumes were analyzed using visual inspection and accuracy in attenuation profiles.
Results: Reconstruction with SS-FDK turned out to be most accurate when scanning without a tilt. Reconstruction with ACE provided major improvements over SS-FDK. The improvements were observed for all three scanning geometries. Impact of the tilt on reconstructions with ACE was shift-variant: the tilt provided benefits at some locations at the cost of degraded image quality at other locations.
Conclusion: C-arm CT imaging of the head can be significantly improved using an algorithm that properly accounts for data redundancy. Orienting the scanning plane to emulate a gantry tilt is not beneficial for reconstruction with short-scan FDK, but could be useful for such a reconstruction algorithm when a region-of-interest is a-priori known. Further evaluation with real patient data is underway.
Funding Support, Disclosures, and Conflict of Interest: This work was partially supported by a research contract between The University of Utah and Siemens Medical Solutions. The concepts and information presented in this abstract are based on research and are not commercially available.
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