Feasibility, image quality and radiation dose of coronary CT angiography (CCTA) in patients with atrial fibrillation using a new generation 256 multi-detector CT (MDCT) Poster No.: C-2378 Congress: ECR 2016 Type: Scientific Exhibit Authors: L. Macron, J.-L. Sablayrolles, J. Feignoux; Saint-Denis/FR Keywords: Cardiac, Vascular, CT, CT-Angiography, Dosimetry, Artifacts DOI: 10.1594/ecr2016/C-2378 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 15
Aims and objectives Several multicenter studies have demonstrated the very good diagnostic accuracy of 64- MDCT (Se 95-99%, Sp 64-83% and NPV 97-99%) for the identification of patients with at least one coronary artery stenosis by ICA. AFib is the most common cardiac arrhythmia and its prevalence and incidence increases with age (Fuster V. et al. Circulation 2006). AFib is considered as a contraindication for CCTA due to increased heart rate variation which can lead to severe motion artifacts (figure 1) Moreover, due to the retrospective nature of current CCTA protocols in AFib, it is associated with significantly higher effective radiation dose than in patients with sinus rythm (Vorre MM et al. Radiology 2013) We sought to evaluate the feasibility of low-dose CCTA in AFib patients despite high heart rate variability with a new generation 256-MDCT thanks to whole heart coverage within one beat and high rotation speed. Page 2 of 15
Images for this section: Fig. 1: Motion artifacts and poor image quality in AFib patients with 64-MDCT Page 3 of 15
Methods and materials Thirty consecutive patients (mean HR 81.4±24.0 bpm, 44 to 151bpm) with AF underwent CCTA on a 256-MDCT (Revolution CT, General Electric). Prevalence and impact on diagnosis of motion and step artifacts were independently evaluated by two experienced readers using a 3-point scale (0: no artifact; 1: artifacts without interference on diagnosis; 2: artifacts interfere with diagnosis. Figures 2 to 4) and percentage of assessable coronary segments was calculated. Contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were measured for quantitative assessment. Radiation dose was evaluated by calculating the mean effective dose (ED). Page 4 of 15
Images for this section: Fig. 1: Motion artifacts and poor image quality in AFib patients with 64-MDCT Page 5 of 15
Fig. 2: Patient in AFib. CCTA on a 256-MDCT. Excellent IQ with a perfect vessel opacification and no motion artifact. Page 6 of 15
Fig. 3: Patient in AFib. CCTA on a 256-MDCT. Average IQ. Page 7 of 15
Fig. 4: Patient in AFib. Poor IQ due to poor vessel opacification and noise-related blurring artifact. Page 8 of 15
Results Population characteristics are summarized in table 1. Overall Image Quality (IQ) was # average in 93% patients. Only 2 patients exhibited a poor image quality due to motion artifacts and sub-optimal vessel opacification. No step artefact was observed thanks to the one-beat whole heart acquisition (figure 5) No impact of HR (median value 81bpm; p=0.96) and HR variation (median value 37.5bpm; p=0.56) on image quality was observed (Figure 6) Most important, 99.3% segments (447/450 segments) were assessable in the overall population. Only 2 RCA segments and one distal circumflex were not assessable due to motion artefacts (figure 7) The mean CNR and mean SNR were respectively 13.3±4.6 and 13.0±3.3. ED remains low with an average of 2.5±1.3 msv. Page 9 of 15
Images for this section: Table 1: Population characteristics Page 10 of 15
Fig. 5: CCTA of a 86y. woman in atrial fibrillation. One-beat whole heart acquisition with a large-detector 256-MDCT (Revolution CT, GE Healthcare) allowing for ruling out CAD in this patient despite challenging conditions. Page 11 of 15
Fig. 6: Impact of heart rate and heart rate variation on image quality Page 12 of 15
Fig. 7: Coronary segments assessability on a per-patient analysis. Page 13 of 15
Conclusion CCTA is feasible in AF patients using a new generation 256-MDCTproviding good image quality and low radiation dose in this challenging population. Further investigations with comparison to invasive coronary angiography are needed in order to confirm a benefit in term of coronary CTA diagnostic accuracy with this new 256- MDCT system. Page 14 of 15
References none Page 15 of 15