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Objective: To evaluate the association between aortic arch calcifications (AAC) on chest radiography and coronary artery calcium (CAC) score determined by CT. Methods: A total of 128 patients (75 men; 69.3 ± 14.7 years) who underwent chest radiography and CAC scoring at CT were included in this retrospective analysis. The extent of AAC on chest radiography was evaluated independently by two blinded observers using a semi-quantitative four-point scale (0-3). Intra- and interobserver agreement was assessed by weighted ĸ statistics. Amount of AAC determined on radiography was correlated with CAC and ROC analyses performed to characterise the diagnostic performance of AAC grading. Results: Excellent intraobserver ( ĸ = 0.82) and good interobserver ( ĸ = 0.75) agreement of AAC grading was noted. Moderate agreement ( ĸ = 0.46, 95 % CI 0.36-0.56) with a linear trend ( P < 0.0001) between AAC grades and CAC scores was found. Cut-off between AAC grades 0-2 and 3 had a sensitivity of 38.6 %, specificity of 96.4 %, PPV of 85.0 %, NPV of 75.0 % and accuracy of 76.6 % for the correct identification of CAC scores greater than 400. Conclusion: Semi-quantitative AAC grading on chest radiography is reliable and positively associated with CAC scoring. We propose to report the extent of AAC in comprehensive radiological reports as 'not present', 'moderate' or 'severe', as severe AAC strongly suggests coronary artery calcification. Key Points: • Semi-quantitative aortic arch calcification (AAC) grading on plain chest radiography appears reliable. • AAC grading is positively associated with CT coronary artery calcium scoring. • AAC grading has a high specificity for ruling out CAC scores greater than 400. • We propose the reporting of the extent of AAC grade in chest X-ray (CXR) reports. [ABSTRACT FROM AUTHOR]

Objectives: Fractional flow reserve computed tomography (FFRCT) depends upon nitroglycerin (NTG) inducing maximal hyperemia. However, the impact of NTG dosages on FFRCT analysis including coronary volume-to-mass ratio (V/M) is unknown.Methods: Eighty patients with repeat coronary CT angiograms (CCTAs) with different sublingual spray NTG doses (0.4 mg and 0.8 mg) were retrospectively analyzed with 45 patients excluded. Patient and scan demographics, post-stenosis and nadir FFRCT values, coronary volume, and coronary volume-to-mass ratio (V/M) were compared at initial CCTA (0.4 mg NTG) and follow-up CCTA (0.8 mg NTG). Differences were compared by Wilcoxon signed-rank test.Results: Thirty-five patients were included (time between CCTAs, 3.9 ± 1.6 years). Segment involvement score was 2.4 ± 3.3 and 2.8 ± 3.4 at initial and repeat CCTA (0.4 and 0.8 mg NTG), respectively (p = 0.004). There was similar image quality (4.1 ± 0.7 vs 4.1 ± 0.8; p = 0.51). Nadir FFRCT values did not differ in the left (0.4 mg, 0.80 ± 0.08 vs 0.8 mg, 0.80 ± 0.03; p = 0.66), right (0.4 mg, 0.90 ± 0.04 vs 0.8 mg, 0.90 ± 0.06; p = 0.25), or circumflex coronaries (0.4 mg, 0.87 ± 0.06 vs 0.8 mg, 0.88 ± 0.06; p = 0.34). Post-stenosis FFRCT values did not differ (p = 0.65). Coronary volume increased with 0.8 mg of NTG (2639 ± 753 mm3 vs 2844.8 ± 827 mm3; p = 0.009) but V/M ratio did not (p = 0.20).Conclusions: Use of 0.8 mg versus 0.4 mg of NTG in routine clinical CCTAs significantly increased coronary volume determined from FFRCT analysis but did not alter FFRCT or V/M. Further evaluation of repeat CCTAs in a more contemporaneous fashion using varied nitrate doses and disease severity is needed.Key Points: • Fractional flow reserve from computed tomography (FFRCT) is a noninvasive method for evaluating the coronary arteries and relies on nitroglycerin (NTG) to induce coronary vasodilation, but the impact of different NTG dosages is unknown. • Retrospective analysis evaluated use of different NTG doses on FFRCT. • Increased NTG dose increased coronary luminal volume on FFRCTanalysis, but did not change FFRCTvalues. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the performance of three-dimensional semi-automated evaluation software for the assessment of myocardial blood flow (MBF) and blood volume (MBV) at dynamic myocardial perfusion computed tomography (CT). Methods: Volume-based software relying on marginal space learning and probabilistic boosting tree-based contour fitting was applied to CT myocardial perfusion imaging data of 37 subjects. In addition, all image data were analysed manually and both approaches were compared with SPECT findings. Study endpoints included time of analysis and conventional measures of diagnostic accuracy. Results: Of 592 analysable segments, 42 showed perfusion defects on SPECT. Average analysis times for the manual and software-based approaches were 49.1 ± 11.2 and 16.5 ± 3.7 min respectively ( P < 0.01). There was strong agreement between the two measures of interest (MBF, ICC = 0.91, and MBV, ICC = 0.88, both P < 0.01) and no significant difference in MBF/MBV with respect to diagnostic accuracy between the two approaches for both MBF and MBV for manual versus software-based approach; respectively; all comparisons P > 0.05. Conclusions: Three-dimensional semi-automated evaluation of dynamic myocardial perfusion CT data provides similar measures and diagnostic accuracy to manual evaluation, albeit with substantially reduced analysis times. This capability may aid the integration of this test into clinical workflows. Key Points: • Myocardial perfusion CT is attractive for comprehensive coronary heart disease assessment. • Traditional image analysis methods are cumbersome and time-consuming. • Automated 3D perfusion software shortens analysis times. • Automated 3D perfusion software increases standardisation of myocardial perfusion CT. • Automated, standardised analysis fosters myocardial perfusion CT integration into clinical practice. [ABSTRACT FROM AUTHOR]

Objectives: Performance evaluation of a fully automated system for calculating computed tomography (CT) coronary artery calcium scores from contrast medium-enhanced coronary CT angiography (cCTA) studies. Methods: One hundred and twenty-seven patients (58 ± 11 years, 71 men) who had undergone cCTA as well as an unenhanced CT calcium scoring study where included. Calcium scores were computed from cCTA by an automated image processing algorithm and compared with calcium scores obtained by standard manual assessment of unenhanced CT calcium scoring studies. Results were compared vis-a-vis (1) absolute calcium score values, (2) age-, gender- and race-dependent percentiles, and (3) commonly used calcium score risk classification categories. Results: One hundred and nineteen out of 127 (93.7%) studies were successfully processed. Mean Agatston calcium score values obtained by traditional non-contrast CT calcium scoring studies and derived from contrast medium-enhanced cCTA did not significantly differ (235.6 ± 430.5 vs 262.0 ± 499.5; P > 0.05). Calcium score risk categories and Multi-Ethnic Study of Atherosclerosis (MESA) percentiles showed very high correlation (Spearman rank correlation coefficient = 0.97, P < 0.0001/0.95, P < 0.0001) between the two approaches. Conclusions: Calcium score values automatically computed from cCTA are highly correlated with standard unenhanced CT calcium scoring studies. These results suggest a radiation dose- and time-saving potential when deriving calcium scores from cCTA studies without a preceding unenhanced CT calcium scoring study. Key Points: • CT coronary calcium scoring is now widely used for cardiac risk stratification • Derivation of calcium scores from coronary CT angiography saves time and radiation • Automatically derived scores are comparable to conventional coronary artery calcium scores • Patient risk stratification is similar, whether using automatically derived or conventional scores [ABSTRACT FROM AUTHOR]

Objectives: Comparison of coronary artery stent assessment with cardiac CT angiography (cCTA) using traditional filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE), in both full- and half-radiation dose image data.Methods: Dual-source cCTA studies of 37 implanted stents were reconstructed at full- and half-radiation dose with FBP and SAFIRE. Half-dose data were based on projections from one DSCT detector. In-stent noise, signal-to-noise ratio (SNR), and stent-lumen attenuation increase ratio (SAIR) were measured and image quality graded. Stent volumes were measured to gauge severity of beam hardening artefacts.Results: Full-dose SAFIRE reconstructions were superior to full-dose FBP vis-à-vis in-stent noise (21.2 ± 6.6 vs. 35.7 ± 17.5; P < 0.05), SNR (22.1 ± 8.6 vs. 14.3 ± 6.7; P < 0.05), SAIR (19.6 ± 17.6 vs. 33.4 ± 20.4%; P < 0.05), and image quality (4.2 ± 0.86 vs. 3.5 ± 1.0; P < 0.05). Stent volumes were lower measured with SAFIRE (119.9 ± 53.7 vs. 129.8 ± 65.0 mm(3); P > 0.05). Comparing half-dose SAFIRE with full-dose FBP, in-stent noise (26.7 ± 13.0 vs. 35.7 ± 17.5; P < 0.05) and SNR (18.2 ± 6.9 vs. 14.3 ± 6.7; P < 0.05) improved significantly. SAIR (31.6 ± 24.3 vs. 33.4 ± 20.4%; P > 0.05), stent volume (129.6 ± 57.3 vs. 129.8 ± 65.0 mm(3); P > 0.05), and image quality (3.5 ± 1.0 vs. 3.7 ± 1.1; P > 0.05) did not differ. Radiation dose decreased from 8.7 ± 5.2 to 4.3 ± 2.6 mSv.Conclusions: Iterative reconstruction significantly improves imaging of coronary artery stents by CT compared with FBP, even with half-radiation-dose data. [ABSTRACT FROM AUTHOR]

Objective: To prospectively investigate the feasibility, image quality and radiation dose estimates for computed tomography angiography (CTA) of the pulmonary veins and left atrium using prospective electrocardiography (ECG)-triggered sequential dual-source (DS) data acquisition at end-systole in patients with paroxysmal atrial fibrillation undergoing radiofrequency ablation.Methods: Thirty-five patients (mean age 66.2 +/- 12.6 years) with paroxysmal atrial fibrillation underwent prospective ECG-triggered sequential DS-CTA with tube current (250 mAs/rotation) centred 250 ms past the R-peak. Tube voltage was adjusted to the BMI (<25 kg/m(2): 100 kV, >25 kg/m(2): 120 kV). Presence of motion or stair-step artefacts was assessed. Effective radiation dose was calculated from the dose-length product.Results: All data sets could be integrated into the electroanatomical mapping system. Twenty-two patients (63%) were in sinus rhythm (mean heart rate 69.2 +/- 11.1 bpm, variability 1.0 +/- 1.7 bpm) and 13 (37%) showed an ECG pattern of atrial fibrillation (mean heart rate 84.8 +/- 16.6 bpm, variability 17.9 +/- 7.5 bpm). Minor step artefacts were observed in three patients (23%) with atrial fibrillation. Mean estimated effective dose was 1.1 +/- 0.3 and 3.0 +/- 0.5 mSv for 100 and 120 kV respectively.Conclusion: Imaging of pulmonary vein anatomy is feasible using prospective ECG-triggered sequential data acquisition at end-systole regardless of heart rate or rhythm at the benefit of low radiation dose. [ABSTRACT FROM AUTHOR]