Coronary artery calcium scoring using a reduced tube voltage and radiation dose protocol with dual-source computed tomography.
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 mm(3) and 149 +/- 392 mm(3) (P = 0.26), with perfect correlation (r = 1.0; P < 0.0001; 95% limits of agreement, -35 to 32 mm(3); bias, -1.4 mm(3)). The mean absolute difference for Agatston scores between the protocols was 16.9, with excellent agreement (kappa = 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).


CONCLUSIONS
A reduced tube current protocol using 100 kVp gives equivalent CCS results at reduced radiation exposure compared with a standard protocol at 120 kVp.
Nakazato
Ryo
R
Department of Imaging, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Taper Building Room 1258, Los Angeles, CA 90048, USA.
Dey
Damini
D
Gutstein
Ariel
A
Le Meunier
Ludovic
L
Cheng
Victor Y
VY
Pimentel
Raymond
R
Paz
William
W
Hayes
Sean W
SW
Thomson
Louise E J
LE
Friedman
John D
JD
Berman
Daniel S
DS
D000368:Aged; D016477:Artifacts; D002114:Calcinosis / Q000000981:diagnostic imaging*; D017023:Coronary Angiography / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000295:instrumentation