Program Information
Quantification of Coronary Artery Cross-Sectional Area in CT Angiography Using Integrated Density: A Phantom Study
T Johnson*, H Ding , M Torabzadeh , S Molloi , University of California, Irvine, CA
Presentations
SU-C-207-7 (Sunday, July 12, 2015) 1:00 PM - 1:55 PM Room: 207
Purpose: To investigate the feasibility of quantifying the cross-sectional area (CSA) of coronary arteries using integrated density in a physics-based model with a phantom study.
Methods: In this technique the total integrated density of the object as compared with its local background is measured so it is possible to account for the partial volume effect. The proposed method was compared to manual segmentation using CT scans of a 10 cm diameter Lucite cylinder placed inside a chest phantom. Holes with cross-sectional areas from 1.4 to 12.3 mm² were drilled into the Lucite and filled with iodine solution, producing a contrast-to-noise ratio of approximately 26. Lucite rods 1.6 mm in diameter were used to simulate plaques. The phantom was imaged with and without the Lucite rods placed in the holes to simulate diseased and normal arteries, respectively. Linear regression analysis was used, and the root-mean-square deviations (RMSD) and errors (RMSE) were computed to assess the precision and accuracy of the measurements. In the case of manual segmentation, two readers independently delineated the lumen in order to quantify the inter-reader variability.
Results: The precision and accuracy for the normal vessels using the integrated density technique were 0.32 mm² and 0.32 mm², respectively. The corresponding results for the manual segmentation were 0.51 mm² and 0.56 mm². In the case of diseased vessels, the precision and accuracy of the integrated density technique were 0.46 mm² and 0.55 mm², respectively. The corresponding results for the manual segmentation were 0.75 mm² and 0.98 mm². The mean percent difference for the two readers was found to be 8.4%.
Conclusion: The CSA based on integrated density had improved precision and accuracy as compared with manual segmentation in a Lucite phantom. The results indicate the potential for using integrated density to improve CSA measurements in CT angiography.
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