Coronary Artery Calcium: A Multi-institutional, Multimanufacturer International Standard for Quantification at Cardiac CT

Purpose: To develop a consensus standard for quantification of coronary artery calcium (CAC).

Materials and Methods: A standard for CAC quantification was developed by a multi-institutional, multimanufacturer international consortium of cardiac radiologists, medical physicists, and industry representatives. This report specifically describes the standardization of scan acquisition and reconstruction parameters, the use of patient size–specific tube current values to achieve a prescribed image noise, and the use of the calcium mass score to eliminate scanner- and patient size–based variations. An anthropomorphic phantom containing calibration inserts and additional phantom rings were used to simulate small, medium-size, and large patients. The three phantoms were scanned by using the recommended protocols for various computed tomography (CT) systems to determine the calibration factors that relate measured CT numbers to calcium hydroxyapatite density and to determine the tube current values that yield comparable noise values. Calculation of the calcium mass score was standardized, and the variance in Agatston, volume, and mass scores was compared among CT systems.

Results: Use of the recommended scanning parameters resulted in similar noise for small, medium-size, and large phantoms with all multi–detector row CT scanners. Volume scores had greater interscanner variance than did Agatston and calcium mass scores. Use of a fixed calcium hydroxyapatite density threshold (100 mg/cm3), as compared with use of a fixed CT number threshold (130 HU), reduced interscanner variability in Agatston and calcium mass scores. With use of a density segmentation threshold, the calcium mass score had the smallest variance as a function of patient size.

Conclusion: Standardized quantification of CAC yielded comparable image noise, spatial resolution, and mass scores among different patient sizes and different CT systems and facilitated reduced radiation dose for small and medium-size patients.

© RSNA, 2007

References

  • 1 Marincek B, Ros PR, Reiser M, Baker ME. Multislice CT: a practical guide. New York, NY: Springer-Verlag, 2001. Google Scholar
  • 2 Fishman EK, Jeffrey RB Jr. Multidetector CT: principles, techniques, and clinical applications. Philadelphia, Pa: Lippincott Williams & Wilkins, 2004. Google Scholar
  • 3 Flohr T, Ohnesorge B, Bruder H, et al. Image reconstruction and performance evaluation for ECG-gated spiral scanning with a 16-slice CT system. Med Phys 2003; 30(10): 2650–2662. Crossref, MedlineGoogle Scholar
  • 4 Kachelriess M, Ulzheimer S, Kalender WA. ECG-correlated image reconstruction from subsecond multi-slice spiral CT scans of the heart. Med Phys 2000; 27(8): 1881–1902. Crossref, MedlineGoogle Scholar
  • 5 Raggi P, Callister TQ, Cooil B, et al. Identification of patients at increased risk of first unheralded acute myocardial infarction by electron-beam computed tomography. Circulation 2000; 101(8): 850–855. Crossref, MedlineGoogle Scholar
  • 6 Wexler L, Brundage B, Crouse J, et al. Coronary artery calcification: pathophysiology, epidemiology, imaging methods, and clinical implications—a statement for health professionals from the American Heart Association. Writing Group. Circulation 1996; 94(5): 1175–1192. Google Scholar
  • 7 Ulzheimer S, Kalender WA. Assessment of calcium scoring performance in cardiac computed tomography. Eur Radiol 2003; 13(3): 484–497. Crossref, MedlineGoogle Scholar
  • 8 Arad Y, Spadaro LA, Goodman K, Newstein D, Guerci AD. Prediction of coronary events with electron beam computed tomography. J Am Coll Cardiol 2000; 36(4): 1253–1260. Crossref, MedlineGoogle Scholar
  • 9 Sell JC, Halliburton SS. Calcium scoring database. International Consortium on Standardization in Cardiac CT Web site. Available at: https://clinapps.bio.ri.ccf.org/cascore/. Accessed December 2004. Google Scholar
  • 10 McCollough CH, Ulzheimer S, Halliburton SS, White RD, Kalender WA. A multi-scanner, multi-manufacturer, international standard for the quantification of coronary artery calcium using cardiac CT [abstr]. In: Radiological Society of North America scientific assembly and annual meeting program. Oak Brook, Ill: Radiological Society of North America, 2003; 630. Google Scholar
  • 11 Ulzheimer S, Shanneik K, McCollough CH, Halliburton SS, Kalender WA. Advantages of using calcium mass in combination with a calcium density threshold for the quantification of coronary calcium [abstr]. In: Radiological Society of North America scientific assembly and annual meeting program. Oak Brook, Ill: Radiological Society of North America, 2003; 428. Google Scholar
  • 12 Halliburton SS, Sell JC, McCollough CH, Ulzheimer S, Kalender WA, White RD. A Web-based multi-vendor, multi-institutional database of standardized coronary calcium measurements using cardiac CT [abstr]. In: Radiological Society of North America scientific assembly and annual meeting program. Oak Brook, Ill: Radiological Society of North America, 2003; 812. Google Scholar
  • 13 Ulzheimer S, Kachelriess M, Kalendar WA. New phantoms for quality assurance in cardiac CT [abstr]. Radiology 1999; 213(P): 402. Google Scholar
  • 14 Agatston AS, Janowitz WR, Hildner FJ, Zusmer NR, Viamonte M Jr, Detrano R. Quantification of coronary artery calcium using ultrafast computed tomography. J Am Coll Cardiol 1990; 15(4): 827–832. Crossref, MedlineGoogle Scholar
  • 15 Yoon HC, Greaser LE 3rd, Mather R, Sinha S, McNitt-Gray MF, Goldin JG. Coronary artery calcium: alternate methods for accurate and reproducible quantitation. Acad Radiol 1997; 4(10): 666–673. Crossref, MedlineGoogle Scholar
  • 16 Ohnesorge B, Flohr T, Fischbach R, et al. Reproducibility of coronary calcium quantification in repeat examinations with retrospectively ECG-gated multisection spiral CT. Eur Radiol 2002; 12(6): 1532–1540. Crossref, MedlineGoogle Scholar
  • 17 Hong C, Bae KT, Pilgram TK, Zhu F. Coronary artery calcium quantification at multi–detector row CT: influence of heart rate and measurement methods on interacquisition variability initial experience. Radiology 2003; 228(1): 95–100. LinkGoogle Scholar
  • 18 Halliburton SS, Stillman AE, Lieber M, Kasper JM, Kuzmiak SA, White RD. Potential clinical impact of variability in the measurement of coronary artery calcification with sequential MDCT. AJR Am J Roentgenol 2005; 184(2): 643–648. Crossref, MedlineGoogle Scholar
  • 19 Stanford W, Burns TL, Thompson BH, Witt JD, Lauer RM, Mahoney LT. Influence of body size and section level on calcium phantom measurements at coronary artery calcium CT scanning. Radiology 2004; 230(1): 198–205. LinkGoogle Scholar
  • 20 McCollough CH, Kaufmann RB, Cameron BM, Katz DJ, Sheedy PF 2nd, Peyser PA. Electron-beam CT: use of a calibration phantom to reduce variability in calcium quantitation. Radiology 1995; 196(1): 159–165. LinkGoogle Scholar
  • 21 Yoon HC, Goldin JG, Greaser LE 3rd, Sayre J, Fonarow GC. Interscan variation in coronary artery calcium quantification in a large asymptomatic patient population. AJR Am J Roentgenol 2000; 174(3): 803–809. Crossref, MedlineGoogle Scholar
  • 22 Wang S, Detrano RC, Secci A, et al. Detection of coronary calcification with electron-beam computed tomography: evaluation of interexamination reproducibility and comparison of three image-acquisition protocols. Am Heart J 1996; 132(3): 550–558. Crossref, MedlineGoogle Scholar
  • 23 Callister TQ, Cooil B, Raya SP, Lippolis NJ, Russo DJ, Raggi P. Coronary artery disease:improved reproducibility of calcium scoring with an electron-beam CT volumetric method. Radiology 1998; 208(3): 807–814. LinkGoogle Scholar
  • 24 Greaser LE 3rd, Yoon HC, Mather RT, McNitt-Gray M, Goldin JG. Electron-beam CT:the effect of using a correction function on coronary artery calcium quantitation. Acad Radiol 1999; 6(1): 40–48. Crossref, MedlineGoogle Scholar
  • 25 Schmidt B, Kalender WA. A fast voxel-based Monte Carlo method for scanner- and patient-specific dose calculations in computed tomography. In: Guerra AD, ed. Physica medica. Erlangen, Germany: European Journal of Medical Physics, 2002; 43–53. Google Scholar
  • 26 Schmidt B. Dose calculations for computed tomography: reports from the Institute of Medical Physics. Erlangen, Germany: Institute of Medical Physics, 2001; 7. Google Scholar
  • 27 Das M, Martensen J, Zou KH, et al. Coronary calcium screening with low-dose 16-slice multidetector-row CT: which calcium scoring method is most robust? [abstr]. European Radiology Supplements 2004; 14: 539–656. CrossrefGoogle Scholar
  • 28 Shemesh J, Evron R, Koren-Morag N, et al. Coronary artery calcium measurement with multi–detector row CT and low radiation dose: comparison between 55 and 165 mAs. Radiology 2005; 236(3): 810–814. LinkGoogle Scholar
  • 29 Martensen JM, Peldschus K, Yucel E, et al. Influence of patient size and acquisition parameters on coronary calcium scoring: a phantom study with 16-slice multidetector-row CT [abstr]. In: Radiological Society of North America scientific assembly and annual meeting program. Oak Brook, Ill: Radiological Society of North America, 2003; 631. Google Scholar
  • 30 Furuhashi S, Sato Y, Inoue F, Hori Y, Kanmatsuse K, Takahashi M. Evaluation of the plaque texture of means of multislice spiral computed tomography in patients with acute coronary syndrome and stable angina [abstr]. In: Radiological Society of North America scientific assembly and annual meeting program. Oak Brook, Ill: Radiological Society of North America, 2003; 631. Google Scholar
  • 31 Hoffman U, Bull-Stewart AA, Achenbach S, Ferencik M, Brady TJ, O'Donnell C. Interscan and interobserver variability of coronary artery calcium measurements in prospectively triggered multislice CT using conventional scoring methods and calibrated mineral mass [abstr]. In: Radiological Society of North America scientific assembly and annual meeting program. Oak Brook, Ill: Radiological Society of North America, 2003; 631. Google Scholar
  • 32 Devries S, Wolfkiel C, Shah V, Chomka E, Rich S. Reproducibility of the measurement of coronary calcium with ultrafast computed tomography. Am J Cardiol 1995; 75(14): 973–975. Crossref, MedlineGoogle Scholar

Article History

Published in print: 2007