Our goal is to provide accurate, object-independent estimates of contrast-agent concentration using energy- resolved CT. Energy-resolved CT has the potential to reduce the contrast dose and radiation dose of CT angiography exams. Combining energy-resolved CT with targeted K-edge contrast agents facilitates quantitative molecular CT, with the potential for improved spatial resolution (sub-mm), temporal resolution (sub-second) and quantitative accuracy (~5%) compared to nuclear medicine methods. Unlike conventional dual-kVp methods, energy-resolved CT distinguishes contrast materials by their distinct K-edge, enabling direct quantification. However, the accuracy and scan time of energy-resolved CT is currently limited by technological issues. This project develops innovative reconstruction and correction methods to overcome the limitations of energy-resolved CT, while increasing accuracy and reducing dose. This effort will enable faster translation of this beneficia technology into the clinic. We hypothesize that the proposed methods will quantify contrast-agent concentration to within 5% error with a one-second scan time. Specifically, the project will: (1) develop a practical spectral-response correction method, (2) develop region-of-interest material decomposition algorithms to reduce dose and pulse-pileup effects, and (3) develop a method for simultaneous estimation of contrast agent and scatter. The methods will be tested through phantom and animal experiments on our prototype energy-resolved CT system. Successful completion of the project will reduce radiation and contrast dose of CT angiography and provide important information about physiological function and disease states when combined with targeted tracers.

Public Health Relevance

This project will the challenges currently limiting the application of energy-resolved CT technology, with the goal of providing accurate contrast-agent information at fast scan times and low dose so that this new technology can be translated into the clinic.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21EB015094-02
Application #
8598086
Study Section
Biomedical Imaging Technology Study Section (BMIT)
Program Officer
Lopez, Hector
Project Start
2012-12-15
Project End
2014-11-30
Budget Start
2013-12-01
Budget End
2014-11-30
Support Year
2
Fiscal Year
2014
Total Cost
$154,020
Indirect Cost
$27,945
Name
Marquette University
Department
Biomedical Engineering
Type
Schools of Engineering
DUNS #
046929621
City
Milwaukee
State
WI
Country
United States
Zip Code
53201
Schmidt, Taly Gilat; Barber, Rina Foygel; Sidky, Emil Y (2017) A Spectral CT Method to Directly Estimate Basis Material Maps From Experimental Photon-Counting Data. IEEE Trans Med Imaging 36:1808-1819
Foygel Barber, Rina; Sidky, Emil Y; Gilat Schmidt, Taly et al. (2016) An algorithm for constrained one-step inversion of spectral CT data. Phys Med Biol 61:3784-818
Schmidt, Taly Gilat; Zimmerman, Kevin C; Sidky, Emil Y (2015) The effects of extending the spectral information acquired by a photon-counting detector for spectral CT. Phys Med Biol 60:1583-600
Zimmerman, Kevin C; Schmidt, Taly Gilat (2015) Experimental comparison of empirical material decomposition methods for spectral CT. Phys Med Biol 60:3175-91