Comparison of Spiral and Electron Beam Tomography in the evaluation of coronary calcification in asymptomatic persons.   Budoff MJ., Mao S., Zalace CP., Bakhsheshi H, Oudiz RJ. The Dept of Medicine, Div of Cardiology, Harbor-UCLA Medical Center & Saint John's Cardiovascular Research Center, USA   Int J Cardiol 2001 Feb;77(2-3):181-188

Objectives:

 Recently, investigators have begun evaluating the ability of spiral computed tomography (sequence scan mode-SEQ) to measure coronary calcium.

Method:

 Electron Beam Tomography (EBCT) and SEQ studies were performed in 10 women and 23 men, with a mean age of 54  + 9 years. The EBCT study was performed within 4 weeks (mean 11 + 4 days) of the SEQ with no clinical interval event (MI, revascularization).

Results:

	EBCT Calcium Score	Calcium Score Range	Spiral CT   Calcium Score	Calcium Score Range
Mean calcium score	52.1  +  58.6	0 - 175	60.1 +  71.1	0 - 253
7 patients	Zero score		Zero score
3 patients	Zero		Positive score
6 patients	47  + 25.7	9 - 99	Zero
16	Positive score		Positive score

As compared to EBCT, spiral CT had a sensitivity of 74% and a specificity of 70%, for an overall diagnostic accuracy of 73%. The positive and 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 values of the differences between the calcium scores in the two scans on the same subjects divided by the mean of the two scores (Absolute Difference between tests/mean), was 84.5% in this study.

Conclusion:

In asymptomatic persons, spiral CT (using SEQ) provides a limited sensitivity (74%) and specificity (70%) for coronary calcium when compared to EBCT. Caution should be used when evaluating the results of spiral CT coronary calcium especially in patients with relatively low calcium scores (<200).