Læknablaðið - 15.05.2013, Side 22

RANNSÓKN
ENGLISH SUMMARY
Effect of coronary calcification on diagnostic accuracy of
the 64row computed tomography coronary angiography
Guömundsdóttir VK', Andersen K,23, Guðjónsdóttir J2-4
Introduction: Coronary artery calcium is known to complicate the
evaluation of stenoses using computer tomography (CT). The aim of this
study was to analyze the effect of coronary calcification on the diagnos-
tic accuracy of CT coronary angiography in an lcelandic population.
Material and methods: The study was a retrospective analysis of
417 consecutive subjects that underwent CT coronary angiography
and subsequent conventional coronary angiography within 6 months.
Subjects were divided based on total Agatston score: 0, 0.1-10,10.1-
100, 100.1-400, 400.1-750 and >750. Sensitivity, specificity, positive
and negative predictive values were calculated for a50% stenoses
diagnosed with the CT, using the conventional coronary angiography as
a reference. Correlation between Agatston score and e50% stenoses
was calculated.
Results: A total of 1668 coronary artery segments in 417 individuals
were evaluated (68.6% men, mean age 60.2 ± 8.9). The total mean Agat-
ston score was 420 (range from 0-4275). CT detected >50% stenoses
with a sensitivity of 70.1%, specificity of 79.9% and positive and nega-
tive predictive values of 55.4% and 88.2%, respectively. The negative
predictive value was 93.0% for Agatston score zero but 78.3% for Agat-
ston score 750. An Agatston score threshold of 363 predicted s50%
coronary stenoses with 49.6% sensitivity.
Conclusion: Diagnostic accuracy is moderate with good negtive
predictive value and specificity. Although coronary calcification reduces
diagnostic accuracy, negative predictive value is only mildly affected for
Agatston score as high as 400. Agatston score is not a good predictor
of a50% coronary artery stenoses. No particular Agatston score cut-off
level was identified to indicate whether CT angiography was useless or
not.
Key words: Compuíed Tomography, coronary arteries, conventional coronary angiography, coronary artery catcium, Agatston score.
Correspondence: Valdís Klara Guðmundsdóttir, valdisklara@gmail.com
'Department ofradiology, The National University Hospital of lceland,1Faculty of Medicine, University of lceland, 3Department of cardiology, The Nationat University Hospital of
lceland,4Röntgen Domus, Domus Medica.
246 LÆKNAblaðið 2013 /99