OBJECTIVES: Coronary computed tomography angiography (CTA) is increasingly being used for evaluation of coronary artery disease (CAD). As a result of the widely reported potential of carcinogenic risk from x-ray based examinations, many strategies have been developed for dose reduction with CTA. The purpose of this study was to assess the diagnostic accuracy of CTA acquired with a submillisievert fraction of effective radiation dose reconstructed with a model-based iterative reconstruction (MBIR) using invasive coronary angiography (ICA) as a standard of reference.
METHODS: In 36 patients (body mass index range 17 to 39 kg/m2) undergoing ICA for CAD evaluation, a CTA was acquired using very low tube voltage (80 to 100 kV) and current (150 to 210 mA) and was reconstructed with MBIR. CAD (defined as ≥50% luminal narrowing) was assessed on CTA and on ICA.
RESULTS: CTA resulted in an estimated radiation dose exposure of 0.29 ± 0.12 mSv (range 0.16 to 0.53 mSv), yielding 96.9% (436 of 450) interpretable segments. On an intention-to-diagnose basis, no segment was excluded, and vessels with at least 1 nonevaluable segment and no further finding were classified as false positive. This resulted in a sensitivity, specificity, positive, and negative predictive value and accuracy of 100%, 74%, 77%, 100%, and 86% per patient and 85%, 86%, 56%, 96%, and 85% per vessel, respectively.
CONCLUSIONS: The use of MBIR reconstruction allows accurate noninvasive diagnosis of CAD with CTA at a submillisievert fraction of effective radiation dose comparable with a chest x-ray in 2 views. Terrance Smith Womens Jersey
Did the authors examine the impact on identification of wall changes/plaque or ‘only’ luminal stenosis?
Did the authors in this context examine the impact on ‘low contrast resolution’?
Contrast-to-noise ratio and low-contrast object resolution on full- and low-dose MDCT: SAFIRE versus filtered back projection in a low-contrast object phantom and in the liver.
Baker ME, Dong F, Primak A, Obuchowski NA, Einstein D, Gandhi N, Herts BR, Purysko A, Remer E, Vachhani N.
AJR Am J Roentgenol. 2012 Jul;199(1):8-18.
PMID: 22733888. http://www.ncbi.nlm.nih.gov/pubmed/22733888
Our pre-occupation with ‘ultra-low’ radiation dose Radiation exposure, low contrast resolution, and cardiovascular CT Imaging.
Paul Schoenhagen, Mark Baker.
JCCT. September 14, 2014.
http://www.sciencedirect.com/science/article/pii/S1934592514002202