2018 ACC/HRS/NASCI/SCAI/SCCT Expert Consensus Document on Optimal Use of Ionizing Radiation in Cardiovascular Imaging-Best Practices for Safety and Effectiveness, Part 2: Radiological Equipment Operation, Dose-Sparing Methodologies, Patient and Medical Personnel Protection.

The stimulus to create this document was the recognition that ionizing radiation-guided cardiovascular procedures are being performed with increasing frequency, leading to greater patient radiation exposure and, potentially, to greater exposure to clinical personnel. While the clinical benefit of these procedures is substantial, there is concern about the implications of medical radiation exposure. ACC leadership concluded that it is important to provide practitioners with an educational resource that assembles and interprets the current radiation knowledge base relevant to cardiovascular procedures. By applying this knowledge base, cardiovascular practitioners will be able to select procedures optimally, and minimize radiation exposure to patients and to clinical personnel. "Optimal Use of Ionizing Radiation in Cardiovascular Imaging - Best Practices for Safety and Effectiveness" is a comprehensive overview of ionizing radiation use in cardiovascular procedures and is published online. To provide the most value to our members, we divided the print version of this document into 2 focused parts. "Part I: Radiation Physics and Radiation Biology" addresses radiation physics, dosimetry and detrimental biologic effects. "Part II: Radiologic Equipment Operation, Dose-Sparing Methodologies, Patient and Medical Personnel Protection" covers the basics of operation and radiation delivery for the 3 cardiovascular imaging modalities (x-ray fluoroscopy, x-ray computed tomography, and nuclear scintigraphy). For each modality, it includes the determinants of radiation exposure and techniques to minimize exposure to both patients and to medical personnel.

2018 ACC/HRS/NASCI/SCAI/SCCT Expert Consensus Document on Optimal Use of Ionizing Radiation in Cardiovascular Imaging-Best Practices for Safety and Effectiveness, Part 1: Radiation Physics and Radiation Biology: A Report of the American College of Cardiology Task Force on Expert Consensus Decision Pathways Developed in Collaboration With Mended Hearts.

The stimulus to create this document was the recognition that ionizing radiation-guided cardiovascular procedures are being performed with increasing frequency, leading to greater patient radiation exposure and, potentially, to greater exposure for clinical personnel. Although the clinical benefit of these procedures is substantial, there is concern about the implications of medical radiation exposure. The American College of Cardiology leadership concluded that it is important to provide practitioners with an educational resource that assembles and interprets the current radiation knowledge base relevant to cardiovascular procedures. By applying this knowledge base, cardiovascular practitioners will be able to select procedures optimally, and minimize radiation exposure to patients and to clinical personnel. Optimal Use of Ionizing Radiation in Cardiovascular Imaging: Best Practices for Safety and Effectiveness is a comprehensive overview of ionizing radiation use in cardiovascular procedures and is published online. To provide the most value to our members, we divided the print version of this document into 2 focused parts. Part I: Radiation Physics and Radiation Biology addresses the issue of medical radiation exposure, the basics of radiation physics and dosimetry, and the basics of radiation biology and radiation-induced adverse effects. Part II: Radiological Equipment Operation, Dose-Sparing Methodologies, Patient and Medical Personnel Protection covers the basics of operation and radiation delivery for the 3 cardiovascular imaging modalities (x-ray fluoroscopy, x-ray computed tomography, and nuclear scintigraphy) and will be published in the next issue of the Journal.

Approaches to enhancing radiation safety in cardiovascular imaging: a scientific statement from the American Heart Association.

Education, justification, and optimization are the cornerstones to enhancing the radiation safety of medical imaging. Education regarding the benefits and risks of imaging and the principles of radiation safety is required for all clinicians in order for them to be able to use imaging optimally. Empowering patients with knowledge of the benefits and risks of imaging will facilitate their meaningful participation in decisions related to their health care, which is necessary to achieve patient-centered care. Limiting the use of imaging to appropriate clinical indications can ensure that the benefits of imaging outweigh any potential risks. Finally, the continually expanding repertoire of techniques that allow high-quality imaging with lower radiation exposure should be used when available to achieve safer imaging. The implementation of these strategies in practice is necessary to achieve high-quality, patient-centered imaging and will require a shared effort and investment by all stakeholders, including physicians, patients, national scientific and educational organizations, politicians, and industry.

Emerging role of cardiovascular CT and MRI in the evaluation of stroke.

OBJECTIVE. The purposes of this article are to explore the potential for use of CT angiography and MRI and to highlight data suggestive of their usefulness in specific cardiovascular abnormalities. CONCLUSION. The evaluation of stroke requires comprehensive assessment of potential stroke mechanisms, including cardiac sources. Despite an exhaustive search for secondary causes, the precise cause of many strokes remains unknown (cryptogenic). It is well recognized, however, that some of these potential causes occur as a result of embolism from the heart or great vessels. Thus, echocardiography, in particular transesophageal echocardiography, is instrumental in a careful assessment of cardiac causes in selected individuals. Unfortunately, transesophageal echocardiography is invasive, and some patients may have relative or absolute contraindications. Cardiovascular CT angiography and MRI have growing potential compared with conventional cardiovascular echography.

Radiation dose in cardiac imaging: how should it affect clinical decisions?

OBJECTIVE: The purpose of this article is to discuss whether and how the risks of exposure to ionizing radiation should affect clinical decision making in patients with known or suspected cardiovascular disease. CONCLUSION: Although the prevalence of cardiovascular disease and frequency of diagnostic testing has risen dramatically, cardiovascular mortality has declined. Earlier and more accurate detection of cardiovascular disease may play an important role. Concerns regarding excessive radiation exposure from cardiovascular imaging have been raised. Efforts to reduce exposure have included selection of appropriate patients for cardiovascular testing, technologic advances, educational resources, and a directed patient-centered approach to testing.

Developing an action plan for patient radiation safety in adult cardiovascular medicine. Proceedings from the Duke University Clinical Research Institute/American College of Cardiology Foundation/American Heart Association Think Tank Held on February 28, 2011.

Technological advances and increased utilization of medical testing and procedures have prompted greater attention to ensuring the patient safety of radiation use in the practice of adult cardiovascular medicine. In response, representatives from cardiovascular imaging societies, private payers, government and nongovernmental agencies, industry, medical physicists, and patient representatives met to develop goals and strategies toward this end; this report provides an overview of the discussions. This expert "think tank" reached consensus on several broad directions including: the need for broad collaboration across a large number of diverse stakeholders; clarification of the relationship between medical radiation and stochastic events; required education of ordering and providing physicians, and creation of a culture of safety; development of infrastructure to support robust dose assessment and longitudinal tracking; continued close attention to patient selection by balancing the benefit of cardiovascular testing and procedures against carefully minimized radiation exposures; collation, dissemination, and implementation of best practices; and robust education, not only across the healthcare community but also to patients, the public, and media. Finally, because patient radiation safety in cardiovascular imaging is complex, any proposed actions need to be carefully vetted (and monitored) for possible unintended consequences.

Cardiac imaging: Part 2, normal, variant, and anomalous configurations of the coronary vasculature.

OBJECTIVE: Noninvasive imaging of the heart and coronary vasculature using CT and MRI is a new and exciting opportunity for radiologists. The purpose of this pictorial essay is to review normal and variant anatomy of the coronary arteries and of several coronary anomalies that may be clinically significant. The coronary veins and artifacts simulating disease will also be briefly covered. This article will help radiologists learn and review normal coronary anatomy, normal variants, and coronary anomalies and recognize pitfalls, such as coronary veins and artifacts, that may be confusing when first encountered. CONCLUSION: The coronary arteries generally are predictable in their origin, course, and perfusion territories. Standardized reporting systems exist for describing the location of specific lesions, and radiologists who interpret CT and MR coronary images should be aware of and should attempt to integrate these reporting schemes into clinical practice.

Left ventricular noncompaction cardiomyopathy: what do we know?

Noncompaction is a rare and primary genetic cardiomyopathy affecting the left ventricle. The diagnosis is usually established by echocardiography, or, less frequently, by left ventriculography. Cardiac magnetic resonance and electrocardiography-gated multi-detector computed tomography are evolving noninvasive modalities to image cardiac structures, and have the utility to detect noncompacted myocardium. Estimates of the frequency and incidence of left ventricular noncompaction (LVNC) are limited because of the controversy over whether LVNC is a discrete disease entity. There is considerable overlap with dilated cardiomyopathy, apical hypertrophy, and hypertrophic cardiomyopathy. Symptoms, diagnosis, and prognosis are variable because of the heterogeneous nature of these diseases, making treatment often empirical and mimicking the treatment of other cardiomyopathies. However, there are management issues that should be addressed in each patient with LVNC, including genetic testing and family screening, the need for implantable cardioverter defibrillator placement, the role of anticoagulation in prevention of thromboembolic complications, and prescriptions/restrictions for implementation of physical activity.

Radiation dose reduction in CT coronary angiography.

During recent years, technologic advancements in computed tomography (CT) have allowed robust cardiac and coronary imaging. Small, mobile cardiac structures such as the coronary arteries can now be imaged directly and noninvasively with high precision. Given the fact that coronary CT angiography (CCTA) can detect preclinical calcified and noncalcified atherosclerosis, there is potential to revolutionize the management of ischemic heart disease by refining risk stratification and improving outcomes in various clinical settings. However, despite this progress, CT has come under scrutiny as concerns about the level and risk of the radiation exposure of the population grow. Although there are no data to support a direct association between CT imaging and risk of future cancer, health care practitioners should make every effort to minimize radiation exposure to their patients. The purpose of this article is to describe techniques that can reduce radiation dose to patients during CCTA but maintain diagnostic image quality.

Estimated radiation dose associated with cardiac CT angiography.

CONTEXT: Cardiac computed tomography (CT) angiography (CCTA) has emerged as a useful diagnostic imaging modality in the assessment of coronary artery disease. However, the potential risks due to exposure to ionizing radiation associated with CCTA have raised concerns. OBJECTIVES: To estimate the radiation dose of CCTA in routine clinical practice as well as the association of currently available strategies with dose reduction and to identify the independent factors contributing to radiation dose. DESIGN, SETTING, AND PATIENTS: A cross-sectional, international, multicenter, observational study (50 study sites: 21 university hospitals and 29 community hospitals) of estimated radiation dose in 1965 patients undergoing CCTA between February and December 2007. Linear regression analysis was used to identify independent predictors associated with dose. MAIN OUTCOME MEASURE: Dose-length product (DLP) of CCTA. RESULTS: The median DLP of 1965 CCTA examinations performed at 50 study sites was 885 mGy x cm (interquartile range, 568-1259 mGy x cm), which corresponds to an estimated radiation dose of 12 mSv (or 1.2 x the dose of an abdominal CT study or 600 chest x-rays). A high variability in DLP was observed between study sites (range of median DLPs per site, 331-2146 mGy x cm). Independent factors associated with radiation dose were patient weight (relative effect on DLP, 5%; 95% confidence interval [CI], 4%-6%), absence of stable sinus rhythm (10%; 95% CI, 2%-19%), scan length (5%; 95% CI, 4%-6%), electrocardiographically controlled tube current modulation (-25%; 95% CI, -23% to -28%; applied in 73% of patients), 100-kV tube voltage (-46%; 95% CI, -42% to -51%; applied in 5% of patients), sequential scanning (-78%; 95% CI, -77% to -79%; applied in 6% of patients), experience in cardiac CT (-1%; 95% CI, -1% to 0%), number of CCTAs per month (0%; 95% CI, 0%-1%), and type of 64-slice CT system (for highest vs lowest dose system, 97%; 95% CI, 88%-106%). Algorithms for dose reduction were not associated with deteriorated diagnostic image quality in this observational study. CONCLUSIONS: Median doses of CCTA differ significantly between study sites and CT systems. Effective strategies to reduce radiation dose are available but some strategies are not frequently used. The comparable diagnostic image quality may support an increased use of dose-saving strategies in adequately selected patients.

Effect of Promotion via Social Media on Access of Articles in an Academic Medical Journal: A Randomized Controlled Trial.

PURPOSE: To study the effect of a planned social media promotion strategy on access of online articles in an established academic medical journal. METHOD: This was a single-masked, randomized controlled trial using articles published in Mayo Clinic Proceedings, a large-circulation general/internal medicine journal. Articles published during the months of October, November, and December 2015 (n = 68) were randomized to social media promotion (SoMe) using Twitter, Facebook, and LinkedIn or to no social media promotion (NoSoMe), for 30 days (beginning with the date of online article publication). Journal website visits and full-text article downloads were compared for 0-30 and 31-60 days following online publication between SoMe versus NoSoMe using a Wilcoxon rank-sum test. RESULTS: Website access of articles from 0 to 30 days was significantly higher in the SoMe group (n = 34) compared with the NoSoMe group (n = 34): 1,070 median downloads versus 265, P < .001. Similarly, full-text article downloads from 0-30 days were significantly higher in the SoMe group: 1,042 median downloads versus 142, P < .001. Compared with the NoSoMe articles, articles randomized to SoMe received a greater number of website visits via Twitter (90 vs 1), Facebook (526 vs 2.5), and LinkedIn (31.5 vs 0)-all P < .001. CONCLUSIONS: Articles randomized to SoMe were more widely accessed compared with those without social media promotion. These findings show a possible role, benefit, and need for further study of a carefully planned social media promotion strategy in an academic medical journal.

Measurement of caval blood flow with MRI during respiratory maneuvers: implications for vascular contrast opacification on pulmonary CT angiographic studies.

OBJECTIVE: Transient interruption of the contrast bolus has been described as a physiologic artifact that can sometimes result in poor opacification of the pulmonary arteries on pulmonary CT angiographic studies. To better understand the mechanism underlying this artifact, we used velocity-encoded cine MRI to measure flow in the inferior vena cava (IVC) and superior vena cava (SVC) during respiratory maneuvers. SUBJECTS AND METHODS: Quantitative measurements of SVC and IVC flow per R-R interval were performed on 10 healthy volunteers (six men, four women; median age, 30 years; range, 25-55 years) with a retrospectively ECG-gated velocity-encoded gradient-echo cine sequence on a 1.5-T MRI unit with axial slices at the level of the diaphragm and just below the azygous vein confluence during free breathing, continuous inspiration, breath-hold at end inspiration, Valsalva maneuver, and breath-hold at end expiration. RESULTS: Median flow during free breathing was 38.9 mL in the SVC and 74.3 mL in the IVC, during continuous inspiration was 43.9 mL in the SVC and 113.7 mL in the IVC, during breath-hold at end inspiration was 31.0 mL in the SVC and 56.1 mL in the IVC, during a Valsalva maneuver was 28.9 mL in the SVC and 53.9 mL in the IVC, and during breath-hold at end expiration was 35.3 mL in the SVC and 61.2 mL in the IVC. CONCLUSION: MRI measurements showed a significant increase in caval flow during inspiration and a greater relative increase in blood flow in the IVC than in the SVC. For thoracic CT performed with IV contrast enhancement, deep inspiration before scanning leads to a large influx of IVC blood that does not contain contrast medium and dilutes the contrast bolus, causing poor vascular opacification. Avoiding initial inspiration before scanning is suggested as a way to limit the transient interruption of the contrast bolus artifact.

Defining Quality in Cardiovascular Imaging: A Scientific Statement From the American Heart Association.

The aims of the current statement are to refine the definition of quality in cardiovascular imaging and to propose novel methodological approaches to inform the demonstration of quality in imaging in future clinical trials and registries. We propose defining quality in cardiovascular imaging using an analytical framework put forth by the Institute of Medicine whereby quality was defined as testing being safe, effective, patient-centered, timely, equitable, and efficient. The implications of each of these components of quality health care are as essential for cardiovascular imaging as they are for other areas within health care. Our proposed statement may serve as the foundation for integrating these quality indicators into establishing designations of quality laboratory practices and developing standards for value-based payment reform for imaging services. We also include recommendations for future clinical research to fulfill quality aims within cardiovascular imaging, including clinical hypotheses of improving patient outcomes, the importance of health status as an end point, and deferred testing options. Future research should evolve to define novel methods optimized for the role of cardiovascular imaging for detecting disease and guiding treatment and to demonstrate the role of cardiovascular imaging in facilitating healthcare quality.