Image Gated Cardiac CT LSU Medical Physics Seminar February 4, 2005 Given by Will Hill With advice from Dr. Kip Mathews A presentation of “Automatic Phase Determination for Retrospectively Gated Cardiac CT” from the December 2004 issue of Medical Physics

Introduction and Objectives  What is Gated Cardiac Computed Tomography (CT) ?  Why bother?  What This Lecture will cover:  Basics of CT  Basics of cardiac timing  How this is done now  How the author did it  The author's results

Literature Review  “Automatic Phase Determination for Retrospectively Gated Cardiac CT,” by R. Manzke, Th. Kohler, T. Neilsen, D. Hawkes and M. Grass, Medical Physics  The Essential Physics of Medical Imaging, Lippncott Williams and Wilkins, Second Edition.

The Basics of Computed Tomography  Who Likes Guessing Games?

The Basics of Computed Tomography  How about this one?

The Basics of Computed Tomography  Pretend you can't see through it.

The Basics of Computed Tomography  and that you have x-rays and a counter.

The Basics of Computed Tomography  Ta-dah!

The Basics of Computed Tomography  So, that's how it works.

Timing: Your Heart

Timing: EKG Methods  Triggered  Continuous

Materials and Method  This Method:  Low Pitch Helical Cardiac Scan and ECG  Reconstruction of Low-Resolution 4D Volume  Automatic Motion Calculations  Reconstruction of High Resolution Volumes  Philips MX 8000 IDT 16-line CT system at University Hospital in Ulm, Germany and at the Carmel Hospital in Haifa, Israel.

Similar Low Resolution Volumes

Motion Determination

Motion Map

Results  Simulation Study  Three Patient's Data

Conclusions  Computational Efficiency  similarity is easy  low resolution scans are used first  Automatically Reduces Motion Artifacts  patient and cycle variation are accounted for  different phases can be used for different heart segments by use of new motion maps

The Future  Authors promise larger clinical trials.