Sensitivity of two electron beam tomography protocols for the detection and quantification of coronary artery calcium

AJR Am J Roentgenol. 2000 Dec;175(6):1743-6. doi: 10.2214/ajr.175.6.1751743.


Objective: The purpose of this study was to compare the sensitivity of two electron beam tomography protocols for detection and quantification of coronary artery calcium.

Subjects and methods: We selected 101 patients (57% men, mean age 53 +/- 10 years) to undergo two consecutive electron beam tomography and acquired imaging with both a 6-mm and a 3-mm slicing protocol. Three pixels (area, 1.03 mm(2)) and a minimal density of 130 H were used for definition of calcified plaque.

Results: We found coronary artery calcifications in 46 patients when we used a 6-mm protocol and in 61 patients when we used a 3-mm protocol (p < 0.001). The average total calcium score was 77 (+/-140) with a 6-mm protocol and 251 (+/-395) with a 3-mm protocol (p < 0.005). The average number of calcified lesions per patient was 1.7 for a 6-mm protocol and 3.7 for a 3-mm protocol (p < 0.01). Of 179 individual lesions seen using a 3-mm protocol, 103 (58%) were missed using a 6-mm protocol, and only 27% of the lesions with a calcium score less than or equal to 40 seen with a 3-mm protocol were detected with 6-mm slicing (p < 0.001). The mean lesion attenuation with a 6-mm protocol was 160 (+/-42) H, compared with 218 (+/-44) H with a 3-mm protocol (p < 0.001), indicating a significantly greater partial volume averaging with the former protocol.

Conclusion: A 6-mm slicing protocol is significantly less sensitive than a 3-mm protocol for the detection and quantification of coronary artery calcium. Since one third of coronary events occur in patients with low calcium scores, a 6-mm protocol might be unreliable for risk assessment because of substantial loss of information in this calcium score range.

Publication types

  • Comparative Study

MeSH terms

  • Calcinosis / diagnostic imaging*
  • Calcinosis / epidemiology
  • Clinical Protocols
  • Coronary Disease / diagnostic imaging*
  • Coronary Disease / epidemiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Risk Assessment
  • Sensitivity and Specificity
  • Tomography, X-Ray Computed / methods*