Cardiac Outpouchings: A Multimodality Imaging Review Cardiac outpouchings pose a diagnostic challenge when encountered in practice, as the signs, symptoms, and initial investigations, such as radiographs and electrocardiogram, are nonspecific. They may remain asymptomatic and be incidentally detected. However, a few may present with progressive shortness of breath, thromboembolic complications, arrhythmias, pressure effects, rupture, or even death. Imaging is of paramount importance in establishing an accurate diagnosis, delineating morphology and extent of the lesion along with its hemodynamic significance, planning management, and in the follow-up. The authors declare no conflicts of interest. Correspondence to: Arun Sharma, DM, Department of Cardiovascular Radiology and Endovascular Interventions, All India Institute of Medical Sciences, New Delhi 110029, India (e-mail: drarungautam@gmail.com). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Anomalies of the Coronary Sinus and Its Tributaries: Evaluation on Multidetector Computed Tomography Angiography Imaging of the coronary sinus and its tributaries has gained increasing significance consequent to the development of an array of electrophysiological and interventional procedures using the cardiac venous system, including ablation for arrhythmias, left ventricular pacing, and in the administration of retrograde cardioplegia. Knowledge of the normal anatomy and the possible anomalies and their clinical significance is imperative to circumvent possible complications. A number of coronary sinus (CS) anomalies, both symptomatic and asymptomatic, have been observed with the widespread use of noninvasive cross-sectional imaging for the imaging of the heart. However, it should be kept in mind that even clinically occult lesions of the CS can cause disastrous complications in specific interventions. Hence, a thorough knowledge of the expected anatomy and the possible anomalies involving the CS along with their clinical significance is imperative for the reporting radiologists and the concerned physicians. In this review, we briefly describe the relevant anatomy and embryology and describe the gamut of anomalies pertaining to the CS and its draining veins on multidetector computed tomography angiography along with their clinical importance. The authors declare no conflicts of interest. Correspondence to: Arun Sharma, DM, Department of Cardiovascular Radiology and Endovascular Interventions, Cardiothoracic and Neurosciences Centre, All India Institute of Medical Sciences, New Delhi 110029, India (e-mail: drarungautam@gmail.com). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Review of Thoracic Causes of Systemic Arterial Air Embolism on Computed Tomography Systemic arterial air embolism (SAAE) is a rare but potentially life-threatening condition that may occur when air enters into pulmonary veins or directly into the systemic circulation after pulmonary procedures (biopsy or resection) or penetrating trauma to the lung. While venous air embolism is commonly reported, arterial air embolism is rare. Even a minor injury to the chest along with positive-pressure ventilation can cause SAAE. Small amounts of air may cause neurological or cardiac symptoms depending on the affected arteries, while massive embolism can result in fatal cardiovascular collapse. We discuss the various causes of SAAE, including trauma, computed tomography–guided lung biopsy, and various intervention procedures such as mechanical circulatory support device implantation, coronary catheterization, and atrial fibrillation repair. SAAE diagnosis can be overlooked because its symptoms are not specific, and confirmation of the presence of air in the arterial system is difficult. Although computed tomography is the optimal imaging tool for diagnosis, patient instability and resuscitation often precludes its use. When imaging is performed, awareness of the causes of SAAE allows the radiologist to promptly diagnose the condition and relay findings to the clinicians so that treatment, namely hyperbaric oxygen therapy, may be started promptly. The authors declare no conflicts of interest. Correspondence to: Achala Donuru, MBBS, MRCPCH, DCH, FRCR, Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107 (e-mail: achala.donuru@jefferson.edu). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Pulmonary Artery/Vein Separation Using Single-Phase Computed Tomography: Feasibility and the Influence of Patient Characteristics on Vessel Enhancement Purpose: The purpose of this article was to verify the usefulness and feasibility of a single-phase scan for pulmonary artery/vein separation using a bolus-tracking technique and to evaluate the influence of patient characteristics on differentiation of computed tomography (CT) values between arteries and veins. Material and Methods: A total of 79 patients (60 male individuals and 19 female individuals, mean age 70 y) with suspected lung cancers or metastasis underwent contrast-enhanced chest CT and ultrasonic echocardiography. The CT values of the pulmonary arteries and veins were measured, and the difference in CT values was calculated. The relationships between the difference in CT values and age, weight, height, body surface area, body mass index, cardiac output, cardiac index, trigger time, trigger CT value, and pulmonary transit time were investigated using univariate linear regression analysis. Results: The CT values were 352.8±87.3 HU and 494.6±76.5 HU for the pulmonary arteries and veins, respectively (P<0.001). A significant but weak correlation was seen between the difference in CT values and the height (r=0.24), trigger time (r=0.35), cardiac index (r=−0.25), and pulmonary transit time (r=0.53) (P<0.05). There was no significant correlation between the difference in CT values and the remaining values. Conclusion: The single-phase scan protocol using a bolus-tracking technique is feasible to differentiate CT values between pulmonary arteries and veins. The influence of patient characteristics on the differentiation of CT values lacks impact. Thus, the suggested protocol may be suitable independent of these factors after further validation. The authors declare no conflicts of interest. Correspondence to: Shota Ichikawa, RT, MS, Department of Radiological Technology, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama 710-8602, Japan (e-mail: s-ichikawa@frontier.hokudai.ac.jp). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Impact of Significant Coronary Artery Calcification Reported on Low-Dose Computed Tomography Lung Cancer Screening Background: Coronary artery calcification (CAC) is a common and important incidental finding in low-dose computed tomography (LDCT) performed for lung cancer screening (LCS). The impact of these incidental findings on patient management is unclear. Purpose: The goals of our study were to determine the impact of reporting CAC on patient management and to determine whether standardized reporting of CAC affects the likelihood of future interventions. Methods: In this IRB-approved retrospective study, we queried our LCS database for reports of LDCT performed between January 2016 and September 2018. All reports with significant findings of CAC designated with the letter “S” for any Lung-RADS category were selected. The grading of CAC was extracted from the reports. Medical records were reviewed for each patient to determine demographics, clinical history, medications, and cardiac-related diagnostic and interventional procedures. The changes in management after the report of significant CAC on LDCT were documented. Statistical analysis with Student t test and Pearson χ2 test was performed. Results: A total of 756/3110 patients (mean age: 67±6.4 y; M=466, 61.6%: F=290, 38.4%) were reported to have significant CAC on LDCT for LCS. Of them, 236/756 patients (31.2%) had established coronary artery disease (CAD) at baseline, before the initial LDCT. A change in management was observed in 155/756 patients (20.5%). The most common changes in management included the following: alteration in medication regimen (n=114/155, 73.5%), stress testing (n=65/155, 41.9%), and referral to a cardiologist (36/155, 23.2%). Percutaneous coronary intervention (4, 2.6%) and surgery (3, 1.9%) were uncommon. Changes in management were more common in those without established CAD and in those whose CAC was semiquantitatively graded (35% vs. 25%, P=0.02). Conclusion: CAC is a common significant finding in LDCT for LCS. Reporting of CAC in patients with nonestablished CAD and semiquantitative assessment resulted in changes in management. S.R.D.: Provided independent image analysis for hospital contracted clinical research trial programs for Merck, Pfizer, Bristol Mayer Squibb, Novartis, Roche, Polaris, Cascadian, Abbvie, Gradalis, Clinical Bay, and Zai laboratories, and also received honorarium from Seimens. J.-A.O.S.: Academic author for Elsevier and may receive royalties for her work. B.P.L.: Academic author for Elsevier and may receive royalties for his work. The remaining authors declare no conflicts of interest. Correspondence to: Dexter P. Mendoza, MD, Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, Founders 202, Boston, MA 02114 (e-mail: dpmendoza@mgh.harvard.edu). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

The Association Between Marital Status, Coronary Computed Tomography Imaging Biomarkers, and Mortality in a Lung Cancer Screening Population Purpose: The purpose of this study was to elucidate the impact of being unmarried on coronary computed tomography (CT) imaging biomarkers and mortality in a lung cancer screening population. Materials and Methods: In this retrospective case-control study, 5707 subjects (3777 married; mean age: 61.9±5.1 y and 1930 unmarried; mean age: 61.9±5.3 y) underwent low-dose CT as part of the National Lung Screening Trial (NLST). The median follow-up time was 6.5 (Q1-Q3: 5.6 to 6.9) years. Being unmarried was defined as never married, widowed, separated, or divorced. Being married was defined as married or living as married. Our primary endpoint was cardiovascular disease (CVD)-related death; our secondary endpoint was all-cause mortality. Coronary CT imaging biomarkers (calcium score, density, and volume) on low-dose chest CT scan were calculated using dedicated automatic software. Weighted Cox proportional-hazards regression was performed to examine the association between marital status and death. Kaplan-Meier curves were generated to visualize subject survival. Results: Being unmarried was significantly associated with an increased risk for CVD-related death (hazard ratio [HR]: 1.58; 95% confidence interval [CI]: 1.31-1.91) and all-cause mortality (HR: 1.39; 95% CI: 1.26-1.53), which remained significant even after adjusting for traditional cardiovascular risk factors (HR CVD death: 1.75; 1.44-2.12 and HR all-cause mortality: 1.58; 95% CI: 1.43-1.74) and coronary calcium score (HR CVD death: 1.58; 95% CI: 1.31-1.91 and HR all-cause mortality: 1.40; 95% CI: 1.27-1.54). Conclusions: Being unmarried is associated with an increased CVD-related death and all-cause mortality mainly due to cardiovascular etiology. On the basis of this, marital status might be taken into consideration when assessing individuals’ health status. The authors declare no conflicts of interest. Correspondence to: Csilla Celeng, MD, PhD, Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, Utrecht 3584 CX, The Netherlands (e-mail: c.celeng@umcutrecht.nl). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Accuracy and Time-Efficiency of an Automated Software Tool to Assess Left Ventricular Parameters in Cardiac Magnetic Resonance Imaging Purpose: Routine manual tracing of cardiac contours is time-consuming and subject to variability. A fully automated software tool may improve reading efficiency. This study was performed to assess the accuracy, reliability, and time-efficiency of a fully automated left ventricular (LV) segmentation software tool to calculate LV volumes and function compared with conventional manual contouring. Materials and Methods: Sixty-seven consecutive patients (53 male, mean age 62.5±10.9 y) underwent adenosine stress/rest perfusion cardiac magnetic resonance examination to rule out myocardial ischemia. Double-oblique short-axis 6-mm slice thickness steady-state free precession cine images were acquired to assess LV ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), and stroke volume (SV) using manual contour tracing and a recently developed fully automated software tool. The length of time needed to obtain LV volumes with each segmentation method was also compared. Results: Compared with manual contouring, the fully automated software tool minimally underestimated LV-EF (mean difference of 2.9%±3.9%) and SV (mean difference of 4.4±8.5 mL) and slightly overestimated ESV (mean difference of −6.4±10.8 mL) and LV mass (mean difference of −14±20.4 g). EDV quantification did not statistically differ. Reliability for EF (concordance correlation coefficient [CCC]=0.92, 95% confidence interval [CI], 0.88-0.95), EDV (CCC=0.98, 95% CI, 0.97-0.99), ESV (CCC=0.96, 95% CI, 0.94-0.97), SV (CCC=0.93, 95% CI, 0.89-0.95), and LV mass (CCC=0.84, 95% CI, 0.76-0.89) was very good. The evaluated software allowed to quantify LV parameters with a 79% reduction in the time required for manual contouring (414.7±91 s vs. 85±16.1 s, respectively, P<0.001). Conclusion: Quantification of LV volumes using the evaluated fully automated segmentation software is accurate and time-efficient. The authors declare no conflicts of interest. Correspondence to: Gorka Bastarrika, MD, PhD, EBCR, Department of Radiology, Cardiothoracic Imaging Division, Clínica Universidad de Navarra. Pamplona 31008, Spain (e-mail: bastarrika@unav.es). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Thoracic Radiologists’ Versus Computer Scientists’ Perspectives on the Future of Artificial Intelligence in Radiology Background: There is intense interest and speculation in the application of artificial intelligence (AI) to radiology. The goals of this investigation were (1) to assess thoracic radiologists’ perspectives on the role and expected impact of AI in radiology, and (2) to compare radiologists’ perspectives with those of computer science (CS) experts working in the AI development. Methods: An online survey was developed and distributed to chest radiologists and CS experts at leading academic centers and societies, comparing their expectations of AI’s influence on radiologists’ jobs, job satisfaction, salary, and role in society. Results: A total of 95 radiologists and 45 computer scientists responded. Computer scientists reported having read more scientific journal articles on AI/machine learning in the past year than radiologists (mean [95% confidence interval]=17.1 [9.01-25.2] vs. 7.3 [4.7-9.9], P=0.0047). The impact of AI in radiology is expected to be high, with 57.8% and 73.3% of computer scientists and 31.6% and 61.1% of chest radiologists predicting radiologists’ job will be dramatically different in 5 to 10 years, and 10 to 20 years, respectively. Although very few practitioners in both fields expect radiologists to become obsolete, with 0% expecting radiologist obsolescence in 5 years, in the long run, significantly more computer scientists (15.6%) predict radiologist obsolescence in 10 to 20 years, as compared with 3.2% of radiologists reporting the same (P=0.0128). Overall, both chest radiologists and computer scientists are optimistic about the future of AI in radiology, with large majorities expecting radiologists’ job satisfaction to increase or stay the same (89.5% of radiologists vs. 86.7% of CS experts, P=0.7767), radiologists’ salaries to increase or stay the same (83.2% of radiologists vs. 73.4% of CS experts, P=0.1827), and the role of radiologists in society to improve or stay the same (88.4% vs. 86.7%, P=0.7857). Conclusions: Thoracic radiologists and CS experts are generally positive on the impact of AI in radiology. However, a larger percentage, but still small minority, of computer scientists predict radiologist obsolescence in 10 to 20 years. As the future of AI in radiology unfolds, this study presents a historical timestamp of which group of experts’ perceptions were closer to eventual reality. The authors declare no conflicts of interest. Correspondence to: Haiwei H. Guo, MD, PhD, Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive S-074B, Stanford, CA 94305 (e-mail: henryguo@stanford.edu). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Imaging of Novel Oncologic Treatments in Lung Cancer Part 2: Local Ablative Therapies Conventional approaches to the treatment of early-stage lung cancer have focused on the use of surgical methods to remove the tumor. Recent progress in radiation therapy techniques and in the field of interventional oncology has seen the development of several novel ablative therapies that have gained widespread acceptance as alternatives to conventional surgical options in appropriately selected patients. Local control rates with stereotactic body radiation therapy for early-stage lung cancer now approach those of surgical resection, while percutaneous ablation is in widespread use for the treatment of lung cancer and oligometastatic disease for selected other malignancies. Tumors treated with targeted medical and ablative therapies can respond to treatment differently when compared with conventional therapies. For example, after stereotactic body radiation therapy, radiologic patterns of posttreatment change can mimic disease progression, and, following percutaneous ablation, the expected initial increase in the size of a treated lesion limits the utility of conventional size-based response assessment criteria. In addition, numerous treatment-related side effects have been described that are important to recognize, both to ensure appropriate treatment and to avoid misclassification as worsening tumor. Imaging plays a vital role in the assessment of patients receiving targeted ablative therapy, and it is essential that thoracic radiologists become familiar with these findings. This research was funded in part by the National Institute of Health/National Cancer Institute Cancer Center Support Grant P30 CA008748. The authors, faculty and all staff in a position to control the content of this CME activity and their spouses/life partners (if any) have disclosed that they have no financial relationships with, or financial interests in, any commercial organizations pertaining to this educational activity. Correspondence to: Darragh Halpenny, MBBCh, BAO, Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (e-mail: halpennd@mskcc.org). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Ballistic and Penetrating Injuries of the Chest Ballistic injuries are a major cause of morbidity and mortality in the United States. Unstable patients have high mortality, and only a small subset arrive at the hospital alive. Many patients undergo emergent surgery upon arrival, but a small subset undergo imaging with plain film, computed tomography, and echocardiography. We present a pictorial essay of ballistic and penetrating injuries and their complications with a focus on lung, cardiac, and vascular injury. The authors declare no conflicts of interest. Correspondence to: William Truesdell, MD, Department of Radiology, Long Island Jewish Medical Center, 270-05 76th Ave., Queens, NY 11040 (e-mail: wtruesdel1@northwell.edu). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved