Thomas Henzler MD, Presenter: Nothing to Disclose

U. Joseph Schoepf MD, Abstract Co-Author: Speakers Bureau, Bracco Group Speakers Bureau, General Electric Company Speakers Bureau, Bayer AG Speakers Bureau, Siemens AG Medical Advisory Board, Siemens AG Medical Advisory Board, Bayer AG Research grant, Bayer AG Research grant, Bracco Group Research grant, General Electric Company Research grant, Siemens AG

Walter Huda PhD, Abstract Co-Author: Research support, Siemens AG

Christian Fink MD, Abstract Co-Author: Nothing to Disclose

Stefan Oswald Schoenberg MD, PhD, Abstract Co-Author: Nothing to Disclose

Anthony Marcus Hlavacek MD, Abstract Co-Author: Nothing to Disclose

We aimed to assess the diagnostic performance of ECG-synchronized coronary CT angiography (cCTA), determine the associated radiation exposure adjusted for childrens' size, and to identify the main determinants of radiation exposure in pediatric patients.

We analyzed ECG-synchronized cCTA studies of 73 pediatric patients (24 female, mean age 10.3±5.8 yrs) with known or suspected coronary abnormalities. The studies had been acquired over a four year period during which our CT imaging equipment had been upgraded, our techniques had been continuously refined, increasing measures for radiation dose reduction had been implemented, and staff training had been intensified. The size-adjusted individual effective radiation doses were obtained from effective dose per unit dose length product coefficients, using scaling factors that accounted for scan length, mAs, patient weight, and relative energy imparted. Findings at cCTA were compared with the results of invasive testing, surgery, and/or long-term follow-up in all patients. Statistics used ANOVA, student's t-test, and multivariate analysis. 

Findings at cCTA were confirmed by invasive testing or surgery in all cases, and all patients were event free on follow-up if cCTA results were normal. The mean effective radiation exposure adjusted for size across the study population was 9.3 ± 6.0mSv. Patients scanned with reduced tube voltage (80kV) had lower radiation exposure than patients scanned with 100-120kV (5.6 ± 2.7mSv versus 14.9 ± 5.4mSv; p<0.0001). Patients aged 0-5 years were exposed to less radiation (4.0 ± 1.9mSv) compared to patients aged 5-10 years (7.4 ± 2.9mSv; p≤0.005) and 10-18 years (11.9 ± 6.4mSv; p≤0.0002). Patients who underwent cCTA after December 2007 were exposed to less radiation than those who underwent cCTA before that date (8.0 ± 5.2mSv versus 13.7 ± 6.6mSv; p≤0.002). X-ray tube voltage and current settings were independent predictors of effective radiation exposure.

Non-invasive cCTA performs well for non-invasive coronary artery evaluation in pediatric patients. Rigorous implementation of radiation protection techniques can reduce radiation exposure to levels that are similar to those reported for invasive catheter angiography in this age group.

After other non-invasive tests are exhausted, cCTA should be considered before invasive testing for coronary artery evaluation in neonates and children.

Henzler, T, Schoepf, U, Huda, W, Fink, C, Schoenberg, S, Hlavacek, A, Coronary CT Angiography in Pediatric Patients: Diagnostic Accuracy and Radiation Dose.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9006304.html