Coronary calcium quantification using various calibration phantoms and scoring thresholds.
OBJECTIVE
To compare scoring threshold and calibration method-dependent accuracy and variability of coronary calcium measurements by multidetector computed tomography (MDCT).


METHODS
Ninety-five subjects were scanned with MDCT. We calculated Agatston score and volume score. Mineral mass (MM) was calculated using patient-based and scanner-based calibration methods. Accuracy of calibration was validated using artificial calcium cylinders.


RESULTS
Patient-based and scanner-based calibration permitted accurate quantification of artificial calcium cylinders (bias: 0 mg and -2 mg). In the subjects, the mean relative difference of MM measurements performed at 90 and 130 Hounsfield units threshold (59%) was lower than for Agatston score (94%) and volume score (109%; P < 0.05). Patient-based and scanner-based calibration yielded systematically different MM measurements (bias: 22%).


CONCLUSIONS
MM lowers threshold-dependent variability of coronary calcium measurements. Patient-based and scanner-based calibration allows accurate calcium quantification ex vivo but reveal systematic differences in subjects. Patient-based calibration may better account for subject size and composition.
Ferencik
Maros
M
Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 100 Charles River Plaza, Suite 400, Boston, MA 02114, USA. maros_ferencik@hms.harvard.edu
Ferullo
Ashley
A
Achenbach
Stephan
S
Abbara
Suhny
S
Chan
Raymond C
RC
Booth
Sarah L
SL
Brady
Thomas J
TJ
Hoffmann
Udo
U
D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000032:analysis*; D002138:Calibration; D017023:Coronary Angiography / Q000379:methods*; D003331:Coronary Vessels / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*
D002118:Calcium