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Coronary artery disease is the leading cause of morbidity and mortality. Tools have been developed to accurately diagnose and evaluate coronary artery disease. Coronary CT angiography (CCTA) provides detailed imaging to deliver precise analysis and prognostic information. We sought to compare the radiation dose from a 256-detector-row CT scanner with that from a 64-detector-row CT scanner across a similar profile of patients. Methods: Consecutive patients were screened for the Converge Registry study and, after consenting to be included, were enrolled in accordance with an Institutional Review Board-approved protocol. A control group who underwent 64-row CCTA were matched by age, sex, and body mass index (BMI) with a group who underwent 256-row CCTA. Results: We compared 110 patients in each group. We found that mean dose-length product (DLP) was significantly lower in the 256-row group than in the 64-row group ( P < 0.05). The radiation dose was reduced by 32% with use of the 256-row scanner for BMIs of 18.5-24.9 (DLP, 111.2 vs. 76.1 mGy-cm [1.56 vs. 1.07 mSv]; P < 0.05). For each BMI subgroup, there was a significant decrease in dose. Regression analysis found that with increasing BMIs, DLP significantly increased for both scanners. Conclusion: The 256-row scanner provided CCTA scans at significantly lower radiation doses than the 64-row scanner in different BMI groups, with all other variables accounted for. Lower radiation exposure along with lower contrast requirements can provide images with high diagnostic accuracy and less risk to the patient., (© 2020 by the Society of Nuclear Medicine and Molecular Imaging.)

Introduction: Coronary CT Angiography (CCTA) is a rapidly increasing technique for coronary imaging; however, it exposes patients to ionising radiation. We examined the impact of dose reduction techniques using ECG-triggering, kVp/mAs reduction and high-pitch modes on radiation exposure in a large Australian tertiary CCTA service., Methods: Data on acquisition modes and dose exposure were prospectively collected on all CCTA scans from November 2009 to March 2014 at an Australian tertiary care centre. A dose reduction algorithm was developed using published techniques and implemented with education of medical staff, radiographers and referrers. Associations of CCTA acquisition to radiation over time were analysed with multivariate regression. Specificity in positive CCTA was assessed by correlation with invasive coronary angiography., Results: 3333 CCTAs were analysed. Mean radiation dose decreased from 8.4 mSv to 5.3, 4.4, 3.7, 2.9 and 2.8 mSv (P < 0.001) per year. Patient characteristics were unchanged. Dose reduction strategies using ECG-triggering, kVp/mAs reduction accounted for 91% of the decrease. High-pitch scanning reduced dose by an additional 9%. Lower dose was independently related to lower kVp, heart rate, tube current modulation, BMI, prospective triggering and high-pitch mode (P < 0.01). CCTA specificity remained unchanged despite dose reduction., Conclusion: Implementation of evidence-based CCTA dose reduction algorithm and staff education programme resulted in a 67% reduction in radiation exposure, while maintaining diagnostic specificity. This approach is widely applicable to clinical practice for the performance of CCTA., (© 2019 The Authors and State of Queensland Journal of Medical Radiation Sciences published by John Wiley & Sons Australia, Ltd on behalf of Australian Society of Medical Imaging and Radiation Therapy and New Zealand Institute of Medical Radiation Technology.)

Rationale and Objectives: Novel technology in coronary computed tomographic angiography allows assessment of coronary artery disease with high image quality (IQ). There are currently two wide detector "whole heart" coverage scanners available, which avoid misregistration artifacts. However, there are no data directly comparing IQ between the two scanners. The aim of the current study is to investigate if IQ is different between the most scanners of GE and Toshiba broad detector scanners., Materials and Methods: Prospective, observational, multicenter international cohort study comparing 236 consecutive patients who underwent coronary computed tomographic angiography using whole-heart scanners; 126 patients on scanner S1 ( Aquilion ONE Vision, Toshiba), and 110 patients on scanner S2 (Revolution CT, GE Healthcare). Hounsfield units were measured using regions of interest in the descending aorta at 6 points (cranial slice, level of the visualized first, second, third, and fourth spines, and the caudal slice). We also compared the coverage length (z-axis) of the full width field of view between a single rotation of the two scanners., Results: Evaluating mean CT attenuation values Hounsfield units through the scan range, are progressively reduced across the descending aorta in the S1 group, resulting in the larger difference of contrast brightness between the cranial and caudal slices compared to the S2 group (absolute difference: S2 13.0 ± 4.4 vs S1 141.9 ± 16.4, p < 0.0001; Percent difference: 19.3 ± 2.1 vs -3.4 ± 1.2, <0.0001). The standard deviation (SD) is similar at the cranial slice between the two scanners, however, the S1 group demonstrated higher SD-differential from cranial to caudal than S2 group. Median radiation exposure was significantly lower for the S2 scanner 1.50 ± 0.75 mSv vs the S1 system 1.9 mSv (IQR 1.7-2.7 mSv) (p = 0.01). Z-axis coverage was larger for the S2 scanner 152.5 mm (244 slices × 0.625 mm/slice) than 133 mm for S1 (266 slices × 0.5 mm/slice)., Conclusion: Although both "volume" scanners cover the whole heart z-axis with one beat, scans using the S1 scanner have a larger variability in attenuation values throughout the scan range, resulting in 20% increase in nonuniformity from cranial to caudal slice. Additionally, SD variation across the field of view, a metric of noise, is larger when using the S1 scanner vs the S2 scanner. These results indicate that the GE Revolution CT has more uniform contrast enhancement and more coverage, lower radiation and lower image noise compared to the Toshiba Aquilion ONE Vision system., (Copyright © 2019 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Background: The Coronary Artery Disease Reporting and Data System (CAD-RADS) provides a lexicon and standardized reporting system for coronary CT angiography., Objectives: To evaluate inter-observer agreement of the CAD-RADS among an panel of early career and expert readers., Methods: Four early career and four expert cardiac imaging readers prospectively and independently evaluated 50 coronary CT angiography cases using the CAD-RADS lexicon. All readers assessed image quality using a five-point Likert scale, with mean Likert score ≥4 designating high image quality, and <4 designating moderate/low image quality. All readers were blinded to medical history and invasive coronary angiography findings. Inter-observer agreement for CAD-RADS assessment categories and modifiers were assessed using intra-class correlation (ICC) and Fleiss' Kappa (κ).The impact of reader experience and image quality on inter-observer agreement was also examined., Results: Inter-observer agreement for CAD-RADS assessment categories was excellent (ICC 0.958, 95% CI 0.938-0.974, p < 0.0001). Agreement among expert readers (ICC 0.925, 95% CI 0.884-0.954) was marginally stronger than for early career readers (ICC 0.904, 95% CI 0.852-0.941), both p < 0.0001. High image quality was associated with stronger agreement than moderate image quality (ICC 0.944, 95% CI 0.886-0.974 vs. ICC 0.887, 95% CI 0.775-0.95, both p < 0.0001). While excellent inter-observer agreement was observed for modifiers S (stent) and G (bypass graft) (both κ = 1.0), only fair agreement (κ = 0.40) was observed for modifier V (high risk plaque)., Conclusion: Inter-observer reproducibility of CAD-RADS assessment categories and modifiers is excellent, except for high-risk plaque (modifier V) which demonstrates fair agreement. These results suggest CAD-RADS is feasible for clinical implementation., (Copyright © 2017. Published by Elsevier Inc.)

Background: Coronary CT angiography (CCTA) has high sensitivity, with 3 recent randomized trials favorably comparing CCTA to standard-of-care. Comparison to exercise stress ECG (ExECG), the most available and least expensive standard-of-care worldwide, has not been systematically tested., Methods: CT-COMPARE was a randomized, single-center trial of low-intermediate risk chest pain subjects undergoing CCTA or ExECG after the first negative troponin. From March 2010 to April 2011, 562 patients randomized to either dual-source CCTA (n=322) or ExECG (n=240). Primary endpoints were diagnostic performance for ACS, and hospital cost at 30 days. Secondary endpoints were time-to-discharge, admission rates, and downstream resource utilization., Results: ACS occurred in 24 (4%) patients. ExECG had 213 negative studies and 27 (26%) positive studies for ACS with sensitivity of 83% [95% CI: 36, 99.6%], specificity of 91% [CI: 86, 94%], and ROC AUC of 0.87 [CI: 0.70, 1]. CCTA (>50% stenosis considered positive) had 288 negative studies and 18/35 (51%) positive studies with a sensitivity of 100% [CI: 81.5, 100], specificity of 94% [CI: 91.2, 96.7%], and ROC of 0.97 [CI: 0.92, 1.0; p=0.2]. Despite CCTA having higher odds of downstream testing (OR 2.0), 30 day per-patient cost was significantly lower for CCTA ($2193 vs $2704, p<0.001). Length of stay for CCTA was significantly reduced (13.5h [95% CI: 11.2-15.7], ExECG 19.7h [95% CI: 17.4-22.1], p<0.0005), which drove the reduction in cost. No patient had post-discharge cardiovascular events at 30 days., Conclusions: CCTA had improved diagnostic performance compared to ExECG, combined with 35% relative reduction in length-of-stay, and 20% reduction in hospital costs. These data lend further evidence that CCTA is useful as a first line assessment in emergency department chest pain., (Copyright © 2014. Published by Elsevier Ireland Ltd.)

Exclusion of ischemia is important in patients with newly diagnosed systolic heart failure (HF). We prospectively compared standard-of-care invasive catheter angiography (iCA) and echocardiography to a novel non-invasive strategy of both Coronary Computed Tomographic Angiography (CCTA) and Cardiovascular MRI (CMR) to determine the etiology of myocardial dysfunction Prospective data were collected from consecutive patients referred for iCA to investigate echocardiographically-confirmed new onset HF. CMR (1.5T GE) and dual source CCTA were performed within 2-7 days of iCA. Results were blinded and separately analyzed by expert readers. 426 coronary segments from 28 prospectively enrolled patients were analyzed by CCTA and quantitative iCA. The per-patient sensitivity and specificity of CCTA was 100% and 90%, respectively, negative predictive value (NPV) 100%, positive predictive value (PPV) 78%. Mean ejection fraction by CMR was 24%. Presence of ischemic-type LGE on CMR conferred a 67% sensitivity, 100% specificity, 90% NPV and 100% PPV. Combining CCTA with CMR conferred 100% specificity, 100% sensitivity, 100% PPV and 100% NPV for detection or exclusion of coronary disease. In patients with negative CCTA all invasive angiograms could have been avoided. In addition, two patients with no ischemic LGE by CMR had severe coronary disease on both CCTA and iCA, indicating global hibernation. This is a noteworthy finding in contrast to previous reports which suggested that absence of LGE rules out significant CAD. CCTA with CMR in newly-diagnosed HF enables non-invasive assessment of coronary artery disease, the severity and etiology of myocardial dysfunction and defines suitability for revascularization. Absence of ischemic-type LGE at CMR does not exclude CAD as a cause of LV dysfunction. A first-line strategy of functional and anatomic imaging with CMR and CCTA appears appropriate in newly diagnosed HF.

Coronary CT angiography and coronary calcium scoring offer a new approach to the diagnosis of coronary artery disease (CAD). They hold significant promise in improving patient outcomes, through identification of atherosclerosis and improved risk assessment. Coronary calcium scoring has proven predictive value concerning the occurrence of future cardiovascular events and outperforms current risk evaluation methods such as the Framingham Risk Score. Coronary CT angiography allows visualisation of the coronary artery lumen, detection of stenoses as well as visualisation of both calcified and non-calcified plaque. The accuracy of coronary CT angiography to detect obstructive coronary artery disease has been established by numerous trials. In particular the negative predictive value of the test approaches 100% in low and intermediate risk groups. Outcomes data demonstrate significant prognostic ability of coronary CT angiography. Modern techniques allow substantial reduction of dose values and radiation exposure of coronary CT angiography has significantly fallen. Coronary CT angiography can be reliably performed with doses similar to the level of annual background radiation, and less than one-third of a Tc Sestamibi scan. Coronary CT angiography has been approved for Medicare reimbursement for specific indications when performed by accredited providers. High quality examinations, experience and careful patient selection and preparation are required to ensure optimal results of coronary CT angiography, and to guide clinical decisions., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Assessment of myocardial "blush" by either Myocardial Blush Grade or TIMI Myocardial Perfusion Grade, is the angiographic method currently preferred to confirm myocardial tissue-level perfusion after primary percutaneous intervention. This review focuses on the utility of angiographic "blush" as a simple, widely available, and virtually costless technique for the immediate diagnosis of microvascular impairment at the time of acute catheterization. We comprehensively outline the available evidence behind the "blush," its use in clinical practice, and draw comparisons with other new technologies for assessment of microvascular integrity., (Copyright © 2010 Mosby, Inc. All rights reserved.)

Computed tomographic coronary artery calcium scanning enables cardiovascular risk stratification; however, exposing patients to high radiation levels is an ongoing concern. New-generation computed tomographic systems use lower radiation doses than older systems do. To quantify comparative doses of radiation exposure, we prospectively acquired images from 220 patients with use of a 64-slice GE LightSpeed VCT scanner (control group, n=110) and a 256-slice GE Revolution scanner (study group, n=110). The groups were matched for age, sex, and body mass index; statistical analysis included t tests and linear regression. The mean dose-length product was 21% lower in the study group than in the control group (60.2 ± 27 vs 75.9 ± 22.6 mGy·cm; P

The article offers information related to CT coronary angiography (CTCA) as a first-line diagnostic test for chest pain in Australia. Topics include the advantages over stress testing in detecting CAD (coronary artery disease) and in identifying patients who require medical therapy; the use of preventive pharmacotherapies, such as statins and aspirin, through detection of nonobstructive CAD; and the ability to assess the burden, location and severity of coronary atherosclerotic plaque.

Cardiac imaging is a rapidly evolving field, with improvements in the diagnostic capabilities of non-invasive cardiac assessment. We review the two main emerging technologies in cardiac imaging: computed tomography coronary angiography (CTCA) to evaluate chest symptoms and to exclude coronary artery disease; and cardiovascular magnetic resonance (CMR) for evaluating cardiac morphology, function and presence of scar. CTCA is an excellent "rule out" test, with a negative predictive value approaching 100%. Radiation exposure is no longer a concern for CTCA, with doses routinely < 5 mSv, and as low as < 1 mSv in selected patients. CTCA is useful for excluding coronary artery disease, investigating the anatomy of coronary anomalies or fistulae, and for the patency of coronary bypass grafts. CMR is the reference test for the accurate quantitation of left ventricular and right ventricular size and function. CMR has no ionising radiation, making it particularly suitable for patients with heart failure or congenital heart disease who require longitudinal follow-up. Evaluation of cardiomyopathies (hypertrophic, ischaemic, infiltrative, myocarditis, iron overload or idiopathic) is a unique strength of CMR. Stress perfusion CMR has a strong evidence base and improved spatial and temporal resolution compared with nuclear single-photon emission computed tomography. [ABSTRACT FROM AUTHOR]

Computed tomography coronary angiography (CTCA) is a non-invasive diagnostic modality that provides a comprehensive anatomical assessment of the coronary arteries and coronary atherosclerosis, including plaque burden, composition and morphology. The past decade has witnessed an increase in the role of CTCA for evaluating patients with both stable and acute chest pain, and recent international guidelines have provided increasing support for a first line CTCA diagnostic strategy in select patients. CTCA offers some advantages over current functional tests in the detection of obstructive and non-obstructive coronary artery disease, as well as for ruling out obstructive coronary artery disease. Recent randomised trials have also shown that CTCA improves prognostication and guides the use of guideline-directed preventive therapies, leading to improved clinical outcomes. CTCA technology advances such as fractional flow reserve, plaque quantification and perivascular fat inflammation potentially allow for more personalised risk assessment and targeted therapies. Further studies evaluating demand, supply, and cost-effectiveness of CTCA for evaluating chest pain are required in Australia. This discussion paper revisits the evidence supporting the use of CTCA, provides an overview of its implications and limitations, and considers its potential role for chest pain evaluation pathways in Australia. [ABSTRACT FROM AUTHOR]

Coronary artery disease (CAD) remains the leading cause of adult mortality globally. Targeting known modifiable risk factors has had substantial benefit, but there remains a need for new approaches. Improvements in invasive and noninvasive imaging techniques have enabled an increasing recognition of distinct quantitative phenotypes of coronary atherosclerosis that are prognostically relevant. There are marked differences in plaque phenotype, from the high-risk, lipid-rich, thin-capped atheroma to the low-risk, quiescent, eccentric, nonobstructive calcified plaque. Such distinct phenotypes reflect different pathophysiologic pathways and are associated with different risks for acute ischemic events. Noninvasive coronary imaging techniques, such as computed tomography, positron emission tomography, and coronary magnetic resonance imaging, have major potential to accelerate cardiovascular drug development, which has been affected by the high costs and protracted timelines of cardiovascular outcome trials. This may be achieved through enrichment of high-risk phenotypes with higher event rates or as primary end points of drug efficacy, at least in phase 2 trials, in a manner historically performed through intravascular coronary imaging studies. Herein, we provide a comprehensive review of the current technology available and its application in clinical trials, including implications for sample size requirements, as well as potential limitations. In its effort to accelerate drug development, the US Food and Drug Administration has approved surrogate end points for 120 conditions, but not for CAD. There are robust data showing the beneficial effects of drugs, including statins, on CAD progression and plaque stabilization in a manner that correlates with established clinical end points of mortality and major adverse cardiovascular events. This, together with a clear mechanistic rationale for using imaging as a surrogate CAD end point, makes it timely for CAD imaging end points to be considered. We discuss the importance of global consensus on these imaging end points and protocols and partnership with regulatory bodies to build a more informed, sustainable staged pathway for novel therapies. [ABSTRACT FROM AUTHOR]