More information about text formats
With interest we read the article by Leschka and colleagues
concerning the assessment of coronary atherosclerosis by dual-source
computed tomography coronary angiography (CTCA) and calcium scoring
(CS). The authors propose an imaging pathway consisting of dual-source
CTCA and selective CS in patients with suspicion of significant coronary
atherosclerosis. We have two remarks.
Firstly, as the authors indicat...
Firstly, as the authors indicate in the Results and in Table 1 and 2,
no significant stenoses were detected in patients without coronary
calcium. However, in Figure 2, six patients without coronary stenosis are
considered to have a negative calcium score. We assume this is an error
and that this number should be zero. Then, the total number of patients
with a calcium score of 0 or >= 400 add up to 46, consistent with the
total number of patients mentioned under CS in Table 2.
The sensitivity of coronary calcium for presence of significant
stenoses and the negative predictive value reported by the authors are
100%, in concordance with previous studies that used the gold standard,
electron-beam tomography (EBT) to derive calcium scores.[2,3] In view of
the reported negative predictive value, we propose that CS should be the
initial test in case of suspected significant coronary atherosclerosis.
Thus, further diagnostic imaging procedures with associated radiation dose
and contrast effects can be withheld in almost one-fifth of the clinical
population (14/74). Earlier generations of multi-detector computed
tomography (MDCT) up to single source 64-MDCT were found to underestimate
the amount of coronary calcium compared to EBT. Thus, the prevalence of
coronary calcium is underestimated with single-source MDCT, leading to
unability to reliably exclude coronary calcium. With dual-source CT the
temporal resolution of EBT is approximated. We recently found that dual-
source CT-derived calcium scores are closer to calcium scores derived by
EBT than those by MDCT.
Dual-source CT studies in larger prospective populations should
confirm these findings.
1. Leschka S, Scheffel H, Desbiolles L, et al. Combining dual-source
computed tomography coronary angiography and calcium scoring: added value
for the assessment of coronary artery disease. Heart 2008;94:1154-61.
2. Breen JF, Sheedy PF II, Schwartz RS, et al. Coronary artery
calcification detected with ultrafast CT as an indication of coronary
artery disease. Radiology 1992;185 : 435-439.
3. Laudon DA, Vukov LF, Breen JF, Rumberger JA, Wollan PC, Sheedy PF II.
Use of electron-beam computed tomography in the evaluation of chest pain
patients in the emergency department. Ann Emerg Med1999; 33:15 -21
4. Greuter MJ, Dijkstra H, Groen JM, et al. 64 slice MDCT generally
underestimates coronary calcium scores as compared to EBT: a phantom
study. Med Phys 2007;34:3510-9.
5. Groen JM, Greuter MJ, Vliegenthart R, et al. Calcium scoring using 64-
slice MDCT, dual source CT and EBT: a comparative phantom study. Int J
Cardiovasc Imaging 2008;24:547-56.
Competing interests: none.