Usefulness of additional coronary calcium scoring in low-dose CT coronary angiography with prospective ECG-triggering impact on total effective radiation dose and diagnostic accuracy.
OBJECTIVE
To determine the impact of additional coronary calcium scoring on total effective radiation dose and diagnostic accuracy of low-dose computed tomography coronary angiography (CTCA) with prospective electrocardiogram (ECG) triggering.


METHODS
Sixty-one consecutive patients underwent 64-slice CTCA using prospective ECG triggering, calcium scoring, and invasive quantitative coronary angiography, the latter served as standard of reference. Diagnostic accuracy was calculated for CTCA, calcium scoring, and for the combination of both. Receiver operator characteristic analyses were performed to determine cutoffs for prediction of significant coronary artery stenoses.


RESULTS
Mean effective radiation dose was 2.1 + or - 0.7 mSv (range, 1.0-3.3 mSv) for CTCA and 1.1 + or - 0.1 mSv (range, 0.9-1.4 mSv) for calcium scoring. Per-patient sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 85.7%, 89.2%, and 100% for CTCA, and 72.7%, 82.1%, 82.8%, and 71.9% for calcium scoring. Adding calcium-scoring with a cutoff at 133 in patients aged >50.7 years with nondiagnostic CTCA improved the respective values of diagnostic accuracy of the entire study population to 100%, 96.4%, 97.1%, and 100%; the added value of calcium scoring was confined to only three patients (5%), who were reclassified from false positive to true negative.


CONCLUSIONS
Specificity and PPV of low-dose CTCA may be further improved by combining it with coronary calcium scoring. However, only a fraction of patient may benefit, whereas exposing the entire population to more than 50% increase in effective radiation dose.
Husmann
Lars
L
Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
Herzog
Bernhard A
BA
Burger
Irene A
IA
Buechel
Ronny R
RR
Pazhenkottil
Aju P
AP
von Schulthess
Patrick
P
Wyss
Christophe A
CA
Gaemperli
Oliver
O
Landmesser
Ulf
U
Kaufmann
Philipp A
PA
D000368:Aged; D000369:Aged, 80 and over; D001822:Body Burden; D002114:Calcinosis / Q000150:complications / Q000000981:diagnostic imaging*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000209:etiology; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*