Coronary artery calcium: absolute quantification in nonenhanced and contrast-enhanced multi-detector row CT studies

Radiology. 2002 May;223(2):474-80. doi: 10.1148/radiol.2232010919.


Purpose: (a) To determine the accuracy of multi-detector row computed tomography (CT) in the measurement of the calcium concentration in a cardiac CT calibration phantom and (b) to assess the correlation of a traditional 3-mm section width CT coronary screening protocol and a 1.25-mm section width CT angiography imaging protocol in the quantification of the absolute mass of coronary calcium in patients who underwent both coronary screening and CT angiography with a multi-detector row CT scanner.

Materials and methods: A heart phantom containing calcified cylinders was scanned to determine calibration factors and absolute calcium mass. In 50 patients, the variability (value 1 - value 2/mean value 1 - value 2), limit of agreement (+/-2SD value 1 - value 2), and systematic error (mean value 1 - value 2) of the total amount of coronary calcium calculated at traditional 3-mm section width CT and at 1.25-mm section width CT angiography were determined.

Results: The correlation coefficient between the 3-mm section width, nonenhanced protocol and the 1.25-mm section width CT angiography protocol was very high (r = 0.977) and the mean variability was low (19.7%) for the absolute mass. There was a systematic error of -6.7 mg and a limit of agreement between 45.0 mg and -58.5 mg.

Conclusion: Use of the mass quantification algorithm in combination with a calibration phantom allows accurate quantification of coronary calcium. Measurements of calcium mass obtained at 1.25-mm section width CT angiography have the best agreement with those obtained at the traditional 3-mm section width imaging protocol.

MeSH terms

  • Algorithms
  • Angiography
  • Calcinosis / diagnostic imaging*
  • Coronary Disease / diagnostic imaging*
  • Female
  • Humans
  • Linear Models
  • Male
  • Middle Aged
  • Phantoms, Imaging
  • Statistics, Nonparametric
  • Tomography, X-Ray Computed / methods*