Monte Carlo simulated coronary angiograms of realistic anatomy and pathology models

We have constructed a fourth generation anthropomorphic phantom which, in addition to the realistic description of the human anatomy, includes a coronary artery disease model. A watertight version of the NURBS-based Cardiac-Torso (NCAT) phantom was generated by converting the individual NURBS surfaces of each organ into closed, manifold and non-self-intersecting tessellated surfaces. The resulting 330 surfaces of the phantom organs and tissues are now comprised of ~5×106 triangles whose size depends on the individual organ surface normals. A database of the elemental composition of each organ was generated, and material properties such as density and scattering cross-sections were defined using PENELOPE. A 300 μm resolution model of a heart with 55 coronary vessel segments was constructed by fitting smooth triangular meshes to a high resolution cardiac CT scan we have segmented, and was consequently registered inside the torso model. A coronary artery disease model that uses hemodynamic properties such as blood viscosity and resistivity was used to randomly place plaque within the artery tree. To generate x-ray images of the aforementioned phantom, our group has developed an efficient Monte Carlo radiation transport code based on the subroutine package PENELOPE, which employs an octree spatial data-structure that stores and traverses the phantom triangles. X-ray angiography images were generated under realistic imaging conditions (90 kVp, 10° Wanode spectra with 3 mm Al filtration, ~5×1011 x-ray source photons, and 10% per volume iodine contrast in the coronaries). The images will be used in an optimization algorithm to select the optimal technique parameters for a variety of imaging tasks.

[1]  G S Kassab,et al.  Analysis of blood flow in the entire coronary arterial tree. , 2005, American journal of physiology. Heart and circulatory physiology.

[2]  Daniel R. Bednarek,et al.  TU‐C‐I‐609‐08: A Total‐Imaging‐System Generalized Performance Comparison of An X‐Ray Image Intensifier and a Microangiographic System in Neurovascular Angiography: Effect of Focal Spot and Scatter , 2005 .

[3]  M P Eckstein,et al.  Improving detection of coronary morphological features from digital angiograms. Effect of stenosis-stabilized display. , 1994, Circulation.

[4]  S. Evans.  Catalogue of Diagnostic X-Ray Spectra and Other Data , 1998 .

[5]  N Petoussi-Henss,et al.  ADULT FEMALE VOXEL MODELS OF DIFFERENT STATURE AND PHOTON CONVERSION COEFFICIENTS FOR RADIATION PROTECTION , 2004, Health physics.

[6]  M. Eckstein,et al.  Simulating coronary arteries in x-ray angiograms. , 2000, Medical physics.

[7]  Stephen Rudin,et al.  Study of the generalized MTF and DQE for a new microangiographic system , 2004, SPIE Medical Imaging.

[8]  Stephen Rudin,et al.  Micro-angiography for neuro-vascular imaging. I. Experimental evaluation and feasibility. , 2003, Medical physics.

[9]  Kyle J. Myers,et al.  Morphology-based three-dimensional segmentation of coronary artery tree from CTA scans , 2007, SPIE Medical Imaging.

[10]  Stephen Rudin,et al.  Generalized performance evaluation of x-ray image intensifier compared with a microangiographic system , 2005, SPIE Medical Imaging.

[11]  Stephen Rudin,et al.  Micro-angiography for neuro-vascular imaging. II. Cascade model analysis. , 2003, Medical physics.

[12]  B.M.W. Tsui,et al.  Extension of the 4D NCAT phantom to dynamic X-ray CT simulation , 2003, 2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515).

[13]  K. Hoffmann,et al.  Generalizing the MTF and DQE to include x-ray scatter and focal spot unsharpness: application to a new microangiographic system. , 2005, Medical physics.

[14]  Kyle J Myers,et al.  Efficiency of the human observer compared to an ideal observer based on a generalized NEQ which incorporates scatter and geometric unsharpness: evaluation with a 2AFC experiment , 2005, SPIE Medical Imaging.

[15]  Jay Bartroff,et al.  Automated computer evaluation and optimization of image compression of x-ray coronary angiograms for signal known exactly detection tasks. , 2003, Optics express.

[16]  William Paul Segars,et al.  Development of a new dynamic NURBS-based cardiac-torso (NCAT) phantom , 2001 .

[17]  Kyle J. Myers,et al.  Gender-specific statistical models of pathological coronary arteries for generating simulated angiograms , 2006, SPIE Medical Imaging.

[18]  Daniel R. Bednarek,et al.  Measurement of flow modification in phantom aneurysm model: comparison of coils and a longitudinally and axially asymmetric stent--initial findings. , 2004, Radiology.