title: Coronary calcium quantification using contrast-enhanced dual-energy computed tomography scans.
abstract: The purpose of this study is to evaluate a direct measure of calcium burden by using dual-energy computed tomography (DECT) during contrast-enhanced coronary imaging, potentially eliminating the need for an extra noncontrast X-ray acquisition. The ambiguity of separation of calcium from contrast material on contrast-enhanced images was solved by using virtual noncontrast images obtained by DECT. A new threshold CT number was required to detect the calcium carrying potential risk for adverse coronary events on virtual noncontrast images. Two methods were investigated to determine the 130 HU threshold for DECT scoring. An in vitro anthropomorphic phantom with 29 excised patient calcium plaques inserted was used for both a linear and a logistic regression analysis. An IRB approved in vivo prospective study of six patients was also performed to be used for logistic regression analysis. The threshold found by logistic regression model to define the calcium burden on virtual noncontrast images detects the calcium carrying potential risk for adverse coronary events correctly (2.45% error rate). DECT calcium mass and volume scores obtained by using the threshold correlates with both conventional Agatston and volume scores (r = 0.98, p &lt; 0.001). A conventional CT cardiac exam requires two scans, including a noncontrast scan for calcium quantification and a contrast-enhanced scan for coronary angiography. With the ability to quantify calcium on DECT contrast-enhanced images, a DECT cardiac exam could be accomplished with one contrast-enhanced scan for both calcium quantification and coronary angiography.
authors: Systems of Biological and Health Systems Engineering, Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, AZ 85287, USA. dyamak@asu.edu
authors: Didem
authors: D
authors: Yamak
authors: William
authors: W
authors: Pavlicek
authors: Thomas
authors: T
authors: Boltz
authors: Prasad M
authors: PM
authors: Panse
authors: David
authors: D
authors: Frakes
authors: Metin
authors: M
authors: Akay
mesh_terms: D002118:Calcium / Q000032:analysis*; D003287:Contrast Media; D017023:Coronary Angiography / Q000295:instrumentation / Q000379:methods*; D003331:Coronary Vessels / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D019047:Phantoms, Imaging; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
chemical_list: D003287:Contrast Media; D002118:Calcium
references: Eur Radiol. 2003 Mar;13(3):484-97
references: 12594550
references: Cardiol Clin. 2003 Nov;21(4):521-34
references: 14719566
references: Acad Radiol. 2004 Mar;11(3):286-92
references: 15035519
references: Int J Cardiovasc Imaging. 2008 Jun;24(5):547-56
references: 18038190
references: AJR Am J Roentgenol. 2001 May;176(5):1295-8
references: 11312197
references: Basic Res Cardiol. 2008 Mar;103(2):161-73
references: 18324372
references: Phys Med Biol. 1976 Sep;21(5):733-44
references: 967922
references: Invest Radiol. 2005 Mar;40(3):148-54
references: 15714089
references: Invest Radiol. 2003 Sep;38(9):559-66
references: 12960525
references: Circulation. 1995 Oct 15;92(8):2157-62
references: 7554196
references: J Am Coll Cardiol. 1990 Mar 15;15(4):827-32
references: 2407762
references: Radiology. 2002 May;223(2):474-80
references: 11997555