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

Recently, investigators have begun evaluating the ability of spiral compute d tomography (sequence scan mode-SEQ) to measure coronary calcium. Electron Beam Tomography (EBT) and SEQ studies were performed in 10 women and 23 me n, with a mean age of 54 +/- 9 years. The EBT study was performed within 4 weeks (mean 11 +/- 4 days) of the SEQ with no clinical interval event (MI, revascularization). The mean EBT calcium score (Agatston method) was 52.1 /- 58.6, with a range of 0 to 175. The SEQ mean score was 60.1 +/- 71.1 (ra nge 0 to 253). There were 7 persons with scores of 0 on both scans, and 9 p ersons with scores of zero on either EBT or spiral CT, but not both. Three persons had negative EBT studies where SEQ detected calcium, and 6 persons had EBT detected calcium and negative SEQ studies. The six patients with ne gative SEQ and positive EBT studies had a mean score of 47 +/- 25.7 (range 9 to 99). The remaining sixteen persons had coronary calcium detected on bo th studies. As compared to EBT, spiral CT had a sensitivity of 74% and a sp ecificity of 70%, for an overall diagnostic accuracy of 73%. The positive a nd negative predictive values were 85 and 54%, respectively for SEQ in this study. The absolute difference in scores between the two tests was 29.1 +/ - 28.5 (mean +/- S.D.). The inter-test variability, defined as the mean val ues of the differences between the calcium scores in the two scans on the s ame subjects divided by the mean of the two scores (Absolute Difference bet ween tests/mean), was 84.5% in this study. In asymptomatic persons, spiral CT (using SEQ) provides a limited sensitivity (74%) and specificity (70%) f or coronary calcium when compared to EBT. Caution should be used when evalu ating the results of spiral CT coronary calcium especially in patients with relatively low calcium scores (<200). (C) 2001 Elsevier Science Ireland Lt d. All rights reserved.