N R van der Werf1,2, P A Rodesch3,4, S Si-Mohamed3,4, R W van Hamersvelt5, M J W Greuter6, T Leiner5, L Boussel3,4, M J Willemink7, P Douek3,4. 1. Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands. n.vanderwerf@erasmusmc.nl. 2. Department of Radiology & Nuclear Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands. n.vanderwerf@erasmusmc.nl. 3. Louis Pradel Cardiology Hospital, Hospices Civils de Lyon, Lyon, France. 4. Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France. 5. Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands. 6. Department of Radiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. 7. Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA.
Abstract
OBJECTIVE: The aim of the current study was to systematically assess coronary artery calcium (CAC) detection and quantification for spectral photon-counting CT (SPCCT) in comparison to conventional CT and, in addition, to evaluate the possibility of radiation dose reduction. METHODS: Routine clinical CAC CT protocols were used for data acquisition and reconstruction of two CAC containing cylindrical inserts which were positioned within an anthropomorphic thorax phantom. In addition, data was acquired at 50% lower radiation dose by reducing tube current, and slice thickness was decreased. Calcifications were considered detectable when three adjacent voxels exceeded the CAC scoring threshold of 130 Hounsfield units (HU). Quantification of CAC (as volume and mass score) was assessed by comparison with known physical quantities. RESULTS: In comparison with CT, SPCCT detected 33% and 7% more calcifications for the small and large phantoms, respectively. At reduced radiation dose and reduced slice thickness, small phantom CAC detection increased by 108% and 150% for CT and SPCCT, respectively. For the large phantom size, noise levels interfered with CAC detection. Although comparable between CT and SPCCT, routine protocols CAC quantification showed large deviations (up to 134%) from physical CAC volume. At reduced radiation dose and slice thickness, physical volume overestimations decreased to 96% and 72% for CT and SPCCT, respectively. In comparison with volume scores, mass score deviations from physical quantities were smaller. CONCLUSION: CAC detection on SPCCT is superior to CT, and was even preserved at a reduced radiation dose. Furthermore, SPCCT allows for improved physical volume estimation. KEY POINTS: • In comparison with conventional CT, increased coronary artery calcium detection (up to 156%) for spectral photon-counting CT was found, even at 50% radiation dose reduction. • Spectral photon-counting CT can more accurately measure physical volumes than conventional CT, especially at reduced slice thickness and for high-density coronary artery calcium. • For both conventional and spectral photon-counting CT, reduced slice thickness reconstructions result in more accurate physical mass approximation.
OBJECTIVE: The aim of the current study was to systematically assess coronary artery calcium (CAC) detection and quantification for spectral photon-counting CT (SPCCT) in comparison to conventional CT and, in addition, to evaluate the possibility of radiation dose reduction. METHODS: Routine clinical CAC CT protocols were used for data acquisition and reconstruction of two CAC containing cylindrical inserts which were positioned within an anthropomorphic thorax phantom. In addition, data was acquired at 50% lower radiation dose by reducing tube current, and slice thickness was decreased. Calcifications were considered detectable when three adjacent voxels exceeded the CAC scoring threshold of 130 Hounsfield units (HU). Quantification of CAC (as volume and mass score) was assessed by comparison with known physical quantities. RESULTS: In comparison with CT, SPCCT detected 33% and 7% more calcifications for the small and large phantoms, respectively. At reduced radiation dose and reduced slice thickness, small phantom CAC detection increased by 108% and 150% for CT and SPCCT, respectively. For the large phantom size, noise levels interfered with CAC detection. Although comparable between CT and SPCCT, routine protocols CAC quantification showed large deviations (up to 134%) from physical CAC volume. At reduced radiation dose and slice thickness, physical volume overestimations decreased to 96% and 72% for CT and SPCCT, respectively. In comparison with volume scores, mass score deviations from physical quantities were smaller. CONCLUSION: CAC detection on SPCCT is superior to CT, and was even preserved at a reduced radiation dose. Furthermore, SPCCT allows for improved physical volume estimation. KEY POINTS: • In comparison with conventional CT, increased coronary artery calcium detection (up to 156%) for spectral photon-counting CT was found, even at 50% radiation dose reduction. • Spectral photon-counting CT can more accurately measure physical volumes than conventional CT, especially at reduced slice thickness and for high-density coronary artery calcium. • For both conventional and spectral photon-counting CT, reduced slice thickness reconstructions result in more accurate physical mass approximation.
Authors: Philip Greenland; Joseph S Alpert; George A Beller; Emelia J Benjamin; Matthew J Budoff; Zahi A Fayad; Elyse Foster; Mark A Hlatky; John McB Hodgson; Frederick G Kushner; Michael S Lauer; Leslee J Shaw; Sidney C Smith; Allen J Taylor; William S Weintraub; Nanette K Wenger; Alice K Jacobs Journal: Circulation Date: 2010-11-15 Impact factor: 29.690
Authors: Matthew J Budoff; Stephan Achenbach; Roger S Blumenthal; J Jeffrey Carr; Jonathan G Goldin; Philip Greenland; Alan D Guerci; Joao A C Lima; Daniel J Rader; Geoffrey D Rubin; Leslee J Shaw; Susan E Wiegers Journal: Circulation Date: 2006-10-02 Impact factor: 29.690