Comparison of spiral and electron beam tomography in the evaluation of coronary calcification in asymptomatic persons

Abstract

While we agree with Dr. Silber in his letter concerning our study [ [1] Budoff M.J. Mao S. Zalaco C.P. Bakhsheshi H. Oudiz R.J. Comparison of spiral and electron beam tomography in the evaluation of coronary calcification in asymptomatic persons. Int. J. Cardiol. 2001; 77: 181-188 Abstract Full Text Full Text PDF PubMed Scopus (55) Google Scholar ] that ECG-triggering is pivotal for calcium scoring, the correlation between electron beam tomography (EBT) and multislice computed tomography (MSCT) remains disappointing, especially among scores commonly seen in an asymptomatic population (over 90% of a screening population will have scores <200). A recent study [ [2] Goldin J.G. Yoon H.C. Greaser 3rd, L.E. Heinze S.B. McNitt-Gray M.M. Brown M.S. Sayre J.W. Emerick A.M. Aberle D.R. Spiral versus electron-beam CT for coronary artery calcium scoring. Radiology. 2001; 221: 213-221 Crossref PubMed Scopus (61) Google Scholar ] reported poor correlation between the calcium score results of spiral CT and EBT. The author’s of that study concluded, “Spiral CT has not yet proved to be a feasible alternative to electron-beam CT for coronary artery calcium quantification.” Furthermore, a new and important application of coronary calcification scoring is assessing for progression of atherosclerosis [ [3] Budoff M.J. Raggi P. Coronary artery disease progression assessed by electron beam tomography. Am J Cardiol. 2001; 88: 46E-50E Abstract Full Text Full Text PDF PubMed Scopus (86) Google Scholar ]. Becker et al. found reproducibility with spiral CT to be lower than EBT, due to longer exposure time and the cluster scan technique used in conventional CT. Finally, due to the longer image acquisition time necessary with MSCT, the patient is exposed to significantly higher radiation doses, especially in anterior structures (breast, thyroid, orbits) [ [4] Becker C.R. Kleffel T. Crispin A. Knez A. Coronary artery calcium measurement: agreement of multirow detector and electron beam CT. Am J Roentfenol. 2001; 176: 1295-1298 Crossref PubMed Scopus (264) Google Scholar ]. In one study of radiation dose during coronary calcium measure, CT of the heart at MSCT led to an effective dose which was 38 times higher than at EBT [ [5] Hidajat N. Wolf M. Rademaker J. Knowllmann F.D. Oestmann J.W. Felix R. Radiation dose in CT of the heart for coronary heart disease and CT of the lung for pulmonary embolism: comparisons between single-slice detector CT, multi-slice detector CT and EBT. Radiology. 2000; 217: 374 Google Scholar ]. Thus, until more research is performed, we feel great caution should be used in performing and interpreting MSCT studies of the heart.