Coronary artery calcium scoring using a reduced tube voltage and radiation dose protocol with dual-source computed tomography
Received 13 June 2009; accepted 2 October 2009. published online 15 October 2009.
Background
Technical advances to minimize radiation exposure because of imaging are in accord with the “as low as reasonably achievable” principle.
Objective
We aimed to determine whether coronary calcium scoring (CCS) by multidetector CT at a tube voltage of 100 kVp yields comparable results to the standard 120-kVp protocol while reducing radiation dose.
Methods
Sixty consecutive outpatients were scanned with a dual-source CT scanner with both the120- and 100-kVp protocols. The calcium threshold was 130 Hounsfield units (HUs) for 120 kVp and 147 HU for 100 kVp, as determined from phantom data. All 100-kVp scans were scored by an experienced reader blinded to 120-kVp data.
Results
Image quality was comparable for 100- and 120- kVp scans. Mean Agatston scores for 100 and 120 kVp were 189 ± 484 and 189 ± 498 (P = 0.92), with perfect correlation (r = 1.0; P < 0.0001; 95% limits of agreement, -36 to 37; bias, 0.6). Mean coronary calcium volume scores for 100 and 120 kVp were 143 ± 370 mm3 and 149 ± 392 mm3 (P = 0.26), with perfect correlation (r = 1.0; P < 0.0001; 95% limits of agreement, -35 to 32 mm3; bias, -1.4 mm3). The mean absolute difference for Agatston scores between the protocols was 16.9, with excellent agreement (κ = 0.95; P < 0.0001). Mean effective radiation dose for the 100-kVp protocol was significantly lower (1.17 mSv versus 1.70 mSv; P < 0.0001).
Conclusion
A reduced tube current protocol using 100 kVp gives equivalent CCS results at reduced radiation exposure compared with a standard protocol at 120 kVp.
aDepartment of Imaging, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Taper Building Room 1258, Los Angeles, CA 90048, USA
bDavid Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
cRabin Medical Center, Sackler Medical School of Medicine, Tel-Aviv University, Petah Tikva, Israel
dSiemens Medical Solutions (PET Division), Knoxville, TN, USA
Corresponding author.
Conflict of interest: Ludovic Le Meunier is an employee of Siemens Medical Systems, PET Division. The other authors report no conflicts of interest.
This study was supported by in part by grant 6318 from the Glazer Foundation, Los Angeles, CA, and in part by The Lincy Foundation, Los Angeles, CA. Dr Nakazato is supported in part by a grant from the Society of Nuclear Medicine Wagner-Torizuka Fellowship, Virginia.
Dr Nakazato and Dr Dey contributed equally to this study.
ABSTRACT