William Pavlicek PhD, Presenter: Nothing to Disclose

Mary Beth Peter MS, Abstract Co-Author: Nothing to Disclose

Robert Gene Paden, Abstract Co-Author: Nothing to Disclose

Thomas Frederick Boltz BS, Abstract Co-Author: Nothing to Disclose

Kyung-Kook Park MS, Abstract Co-Author: Nothing to Disclose

Jaynne Leverentz RT, Abstract Co-Author: Employee, General Electric Company

Metin Akay, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to fabricate plaque whose size and shape mimic that found clinically, including having known values of coronary stenosis and plaque material composition.

The plaque phantom was designed to replicate stenosis and soft plaque as a disease in three coronary arteries: right coronary artery, left anterior descending, and left circumflex artery. SolidWorks, a CAD program, was utilized to design the plaque phantoms based on three factors of vulnerability: stenosis, composition and shape. For each artery, a plaque of 40%, 60% and 80% stenosis by diameter was created. Diameters were chosen based upon distal and proximal regions of the coronary arteries. The phantoms were made of four different materials chosen for their variance in Hounsfield units (HU) in order to mimic varying degrees of clinically known plaque composition. 100% glandular, 50% glandular/50% adipose, and 100% adipose 14A mammography phototimer consistency slabs by CIRS as well as Lucite were used. SolidWorks provided the volume of each plaque, which allowed for the phantom density to be determined following mass measurement. The fabrication was completed by a Harding tool room lathe and a Webb CNC milling machine at Arizona State University with a tolerance of 0.1 mm. The plaques were then used in conjunction with a beating heart phantom developed at Mayo Clinic Arizona. The heart phantom offered anatomically correct vessels and appropriate tissue HU units. The plaques were then imaged with a GE VCT scanner using a saline and iodine solution. The observed plaque density and stenosis were compared with the known measured values.

A total of 27 plaques were fabricated. The stenosis percentages used were 40, 60 and 80%. The 100% glandular, 50/50, 100% adipose and Lucite were found to have HU values of 35.2 to 36.55, -32.23 to -43.42, -84.51 to -107.87, and 83.3 to 113.96 respectively.

The plaque phantoms provide a good approximation of coronary soft plaque seen in patients. They are useful in CT testing as they can be imaged repeatedly and reproducibly. Examples of use include stenosis measurement, plaque HU composition determination, and optimization for Dual Energy subtraction acquisition settings.

Improved accuracy of stenosis as well as lipid and fibrous plaque composition with CCTA can potentially improve or aid in the diagnosis of coronary artery disease.

Pavlicek, W, Peter, M, Paden, R, Boltz, T, Park, K, Leverentz, J, Akay, M, et al, , Lipid Plaque Phantom Design and Fabrication.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6011752.html