Low- vs. standard-dose coronary artery calcium scanning.
OBJECTIVE
This study was designed to assess the accuracy of coronary artery calcium scans (CACS) acquired at radiation doses below mammography and low-dose lung scanning, compared with standard-dose CACS.


RESULTS
CACS was performed in 102 consecutive patients at 120 kVp; all were imaged at standard-dose mAs levels ranging from 30 to 80 mAs determined by their weight, with iterative reconstruction (IR) level 3, and at 50% of the standard-dose mAs with IR level 7 to compensate for the expected increased noise with lower mAs. The low- vs. standard-dose mAs was 24.5 ± 8.8 vs. 48.5 ± 17.8 mAs (P < 0.0001), and the radiation exposure was 0.37 ± 0.16 vs. 0.76 + 0.34 mSv (P < 0.0001). The Agatston score correlation between the low and high dose was excellent (r = 0.998, P < 0.0001) over a range of scores from 0 to 2512. The weighted kappa for agreement of standard CAC risk categories was 0.95 (95% CI 0.83-0.97). The mean of the differences between individual low- and standard-dose Agatston scores was 17.4 ± 25.8, lower than the reported variability of two scans performed with the same mAs.


CONCLUSIONS
There was excellent agreement of CACS-based risk classification at low and standard doses, with lower interscan variability than with reported identical doses. The low-dose CACS radiation exposure was less than the approved screening tools of mammography and low-dose lung scanning.
Icahn School of Medicine at Mount Sinai, Mount Sinai Medical Center, One Gustave L. Levy Place, Box 1030, New York, NY 10029-6574, USA harvey.hecht@mountsinai.org hhecht@aol.com.
Harvey S
HS
Hecht
DASA/Delboni R. Dr. Diogo de Faria, 1379 - Vila Clementino São Paulo - SP, Brazil.
Maria Eduarda Menezes
ME
de Siqueira
Icahn School of Medicine at Mount Sinai, Mount Sinai Medical Center, One Gustave L. Levy Place, Box 1030, New York, NY 10029-6574, USA.
Matthew
M
Cham
Icahn School of Medicine at Mount Sinai, Mount Sinai Medical Center, One Gustave L. Levy Place, Box 1030, New York, NY 10029-6574, USA.
Rowena
R
Yip
Icahn School of Medicine at Mount Sinai, Mount Sinai Medical Center, One Gustave L. Levy Place, Box 1030, New York, NY 10029-6574, USA.
Jagat
J
Narula
Icahn School of Medicine at Mount Sinai, Mount Sinai Medical Center, One Gustave L. Levy Place, Box 1030, New York, NY 10029-6574, USA.
Claudia
C
Henschke
Icahn School of Medicine at Mount Sinai, Mount Sinai Medical Center, One Gustave L. Levy Place, Box 1030, New York, NY 10029-6574, USA.
David
D
Yankelevitz
D000368:Aged; D015992:Body Mass Index; D002114:Calcinosis / Q000175:diagnosis / Q000000981:diagnostic imaging*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*
Atherosclerosis; Coronary artery calcium; Radiation