Using Quantitative Computed Tomographic Imaging to Understand Chronic Obstructive Pulmonary Disease and Fibrotic Interstitial Lung Disease: State of the Art and Future Directions Computed tomography (CT) is commonly used in the evaluation and management of patients with diffuse lung pathologies, including chronic obstructive pulmonary disease (COPD) and fibrotic interstitial lung disease (ILD). In clinical practice, the qualitative (visual) assessment of CT images by a radiologist provides insight into the diagnosis of diffuse lung disease, estimates disease severity, and supports the identification of complications. Quantitative CT (qCT) is an emerging technique that provides some advantages over qualitative assessment. qCT can allow early and accurate detection of emphysema and airway disease, as well as aiding the evaluation of disease burden in both COPD and ILD. This approach is starting to be used as a surrogate biomarker in clinical trials to assess response to therapy. Artificial intelligence techniques have recently been incorporated into qCT, with such rapid evolution that it is currently difficult to determine the exact role it will eventually play in evaluating patients with COPD or pulmonary fibrosis. This article reviews the current state of the art for qualitative and qCT assessment of both COPD and fibrotic ILD. Current areas of controversy and limitations of these techniques are discussed, along with the potential future role of artificial intelligence. Recommendations are provided with regard to the current use of these techniques in the management of patients with diffuse lung disease. C.J.R. received grants and honoraria from Boehringer Ingelheim and Hoffmann-La Roche. The remaining authors declare no conflicts of interest. Correspondence to: Cameron J. Hague, MD, Department of Radiology, St. Paul’s Hospital, 1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6 (e-mail: cameron.hague@vch.ca). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Application of Artificial Intelligence–based Image Optimization for Computed Tomography Angiography of the Aorta With Low Tube Voltage and Reduced Contrast Medium Volume Purpose: The purpose of this study was to evaluate the impact of artificial intelligence (AI)-based noise reduction algorithm on aorta computed tomography angiography (CTA) image quality (IQ) at 80 kVp tube voltage and 40 mL contrast medium (CM). Materials and Methods: After obtaining institutional review board approval and 8 written informed consents, 60 patients (35 men, 25 women; age range: 18 to 85 y) referred for aorta CTA examination were assigned to 2 groups at random. Group A underwent an 80 kVp protocol with 40 mL CM (320 mg I/mL). Group A reconstructed with iterative reconstruction was named as group A1 and further AI-based noise reduction was named as group A2. Group B was scanned with standard 120 kVp, 80 mL CM, and iterative reconstruction algorithm. The quantitative assessment of IQ included aorta CT attenuation, noise, signal-to-noise ratio, and contrast-to-noise ratio. A 5-point scale (5—excellent, 1—poor) was used by 2 radiologists independently for qualitative IQ analysis. Results: The image noise significantly decreased while signal-to-noise ratio and contrast-to-noise ratio significantly increased in the order of group A1, B, and A2 (all P<0.05). Compared with group B, the subjective IQ score of group A1 was significantly lower (P<0.05), while that of group A2 had no significant difference (P>0.05). The effective dose and CM volume of group A were reduced by 79.18% and 50%, respectively, than that of group B. Conclusions: The AI-based noise reduction could improve the IQ of aorta CTA with low kV and reduced CM, which achieved the potential of radiation dose and contrast media reduction compared with conventional aorta CTA protocol. Y.W. and M.Y. contributed equally to this work. Supported by National Natural Science Foundation of China (Grant NO. 81471725, 2015); and the Beijing Municipal Natural Science Foundation Interdisciplinary cooperation project (Grant NO. Z171100001117136, 2017); and the MOST “13th Five Year” National Key Research Project of China (Grant NO. 2016YFC1300402, 2016). The authors declare no conflicts of interest. Correspondence to: Zhengyu Jin, MD, PhD, Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Shuaifuyuan, Dongcheng District, Beijing 100730, China (e-mail: jinzy_pumch@126.com). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Pulmonary Computed Tomography Parenchymal and Vascular Features Diagnostic of Postablation Pulmonary Vein Stenosis Purpose: The purpose of this study was to define the full spectrum of pulmonary computed tomography (CT) changes characteristic of postablation pulmonary vein stenosis (PVS). Materials and Methods: We retrospectively reviewed our pulmonary vein isolation database. PVS was graded as follows: grade 1:<50%, grade 2: 50% to 75%, grade 3: 76% to 99%, and grade 4: total occlusion. CT parenchymal and vascular changes were detected and correlated with clinical course and nuclear scans. Results: Of 486 patients who underwent pulmonary vein isolation, 56 patients (11%) were symptomatic, prompting referral to CT evaluation. Grades 1, 2, 3, and 4 PVS were documented in 42, 1, 2, and 11 patients, respectively. Apart from PVS, abnormal CT findings were present only in patients with PVS grades 2 to 4. Pulmonary parenchymal changes (consolidation, “ground glass” opacities, interlobular septal thickening, and volume loss) were found in PVS grades 2 to 4. Pulmonary vascular changes (oligemia, “sluggish flow,” and collateral mediastinal vessels) were shown in patients with grades 3 to 4 PVS. Concomitant nuclear scans documented reduced lung perfusion. All findings were located to the lobe drained by the affected vein. Complete resolution of pulmonary findings on follow-up CT scans was demonstrated in 20% of patients. Eleven stents were inserted in 7 patients with PVS grades 2 to 4, none of which demonstrated radiologic or clinical resolution. Conclusions: A typical CT complex of both parenchymal and vascular findings in the affected lobe is diagnostic of postablation PVS. Lack of clinical and radiologic resolution in most patients, even after stent insertion, further highlights the importance of early recognition of this underdiagnosed condition. E.K.: equal contributor. The authors declare no conflicts of interest. Correspondence to: Orly Goitein, MD, Department of Imaging, Sheba Medical Center, Tel Hashomer, Ramat Gan 52621, Israel (e-mail: orly.goitein@sheba.health.gov.il). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Sonographic Evaluation of Diaphragmatic Dysfunction: Technique, Interpretation, and Clinical Applications Diaphragmatic dysfunction is a potential cause of dyspnea that can lead to significant morbidity. The purpose of this review article is to provide readers with the essentials for performing diaphragm ultrasonography, image interpretation, and the technical limitations one needs to be aware of. Diaphragm ultrasonography is simple to perform and has proven to be an accurate and safe bedside modality, overcoming many of the traditional limitations of fluoroscopy. The authors declare no conflicts of interest. Correspondence to: Farouk Dako, MD, MPH, Department of Radiology, Temple University Hospital, 3401 North Broad Street, Philadelphia, PA 19140 (e-mail: fdako123@gmail.com). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Significant Radiation Dose Reduction Using a Novel Angiography Platform in Patients Undergoing Cryoballoon Pulmonary Vein Isolation Objectives: Cryoballoon pulmonary vein isolation (cPVI) in patients with atrial fibrillation requires fluoroscopic guidance, causing a relevant amount of radiation exposure. Strategies to reduce radiation exposure in electrophysiologic procedures and specifically cPVI are of great importance. The aim of this study was to evaluate a possible reduction of radiation dose using the novel Azurion 7 F12 x-ray system compared with its predecessor Allura FD10. Methods: In February 2017, the Philips Azurion angiography system was introduced, combining the Allura Clarity radiation dose reduction technology with a more powerful generator, improved image resolution, and a large screen display. In 173 patients undergoing cPVI by a single experienced operator in our institution between December 2016 and April 2018, dose area products (cGy×cm2) and image quality were compared using Azurion 7 F12 or Allura FD10 angiography system. Results: A significant reduction in total radiation dose expressed as a dose area products of 524 (332; 821) cGy×cm2 on the Allura system compared with 309 (224; 432) cGy×cm2 on the Azurion system was observed (P<0.001). The number of imaging scenes recorded were 14.7 versus 13.9, and mean overall imaging quality scores (grading 4.85±0.4 with Azurion vs. 4.80±0.4 with Allura, P=0.38) and scores based on specific quality parameters were similar in both groups. Conclusion: Use of the new Azurion 7 F12 angiography system substantially reduced radiation doses compared with the previous generation reference system, Allura Clarity, without compromising imaging quality in patients undergoing cryoballoon pulmonary vein isolation. The authors declare no conflicts of interest. Correspondence to: Martin Schmidt, MD, Kreisklinik Ebersberg, Medizinische Klinik II, Pfarrer-Guggetzer-Str.3, Ebersberg 85560, Germany (e-mail: mschmidtco@t-online.de). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Identification of Patients With Heart Failure From Test Bolus of Computed Tomography Angiography in Patients Undergoing Preoperative Evaluation for Transcatheter Aortic Valve Replacement Purpose: Identify a measurable parameter from test bolus of computed tomography angiography that can differentiate aortic stenosis patients with normal systolic function from those with heart failure and reduced ejection fraction (HFrEF). Materials and Methods: This retrospective study included patients (undergoing evaluation for transcatheter aortic valve replacement) who had retrospective electrocardiogram-gated cardiac computed tomography angiography using test bolus. The measured variables were time to peak contrast enhancement in the pulmonary artery (PAtime), in the ascending (AsAotime) and descending aorta (DsAotime). From these, the pulmonary transit time (PTT: difference between time to peak enhancement in the ascending aorta to peak enhancement in the main pulmonary artery), aortic transit time (ATT: difference between time to peak enhancement in the descending aorta to time to peak enhancement in the ascending aorta) and DsAotime−PAtime were also calculated. Biventricular volumes and function were calculated. The subjects were classified on the basis of ventricular ejection fractions: normal (EF>50%), midrange (EF 40% to 50%), and HF patients with reduced EF (EF<40%). Continuous variables were compared between all groups using ordinary 1-way analysis of variance, while sex was compared using the Fisher exact test. The unpaired t tests were used to compare between the normal and HF groups. Receiver operating characteristic analysis was used in predicting decreased cardiac function (EF<40% vs. EF>50%). Results: AsAotime and PTT were significant predictors of low biventricular EF when controlling for sex and body mass index (AsAotime: odds ratio=0.74 [95% confidence interval=0.61-0.91], P=0.005; PTT: odds ratio=0.64 95% confidence interval=0.46-0.88], P=0.006). A threshold of 23 seconds for AsAotime resulted in 72.1% sensitivity and 71.4% specificity, and 79.1% sensitivity and 64.3% specificity for DsAotime. Conclusions: The time to peak contrast enhancement from the test bolus images correlates with cardiac function. Decreased biventricular systolic dysfunction can be predicted if the time to peak contrast enhancement is >23 seconds in the ascending or descending aorta. The authors declare no conflicts of interest. Reprints: Abhishek Chaturvedi, MD, Department of Imaging Science, University of Rochester Medical Center, 601, Elmwood Avenue, Rochester, NY 14642 (e-mail: toabhic@gmail.com). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Computed Tomography–based Body Composition Analysis and Its Role in Lung Cancer Care Body composition analysis, also referred to as analytic morphomics, morphomics, or morphometry, describes the measurement of imaging biomarkers of body composition such as muscle and adipose tissue, most commonly on computed tomography (CT) images. A growing body of literature supports the use of such metrics derived from routinely acquired CT images for risk prediction in various patient populations, including those with lung cancer. Metrics include cross-sectional area and attenuation of skeletal muscle and subcutaneous, visceral, and intermuscular adipose tissue. The purpose of this review is to provide an overview of the concepts, definitions, assessment tools, segmentation techniques and associated pitfalls, interpretation of those measurements on chest and abdomen CT, and a discussion of reported outcomes associated with body composition metrics in patients with early-stage and advanced lung cancer. F.J.F. receives a related research seed grant from the Society of Thoracic Radiology. M.T. is supported by the Harvard Nutrition and Obesity Research Center NIH P30 DK040561. The remaining authors declare no conflicts of interest. Correspondence to: Florian J. Fintelmann, MD, 55 Fruit Street, FND-202, Boston, MA 02114 (e-mail: fintelmann@mgh.harvard.edu). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Proximal Interruption of the Pulmonary Artery and Unilateral Pulmonary Vein Atresia No abstract available

Proximal Interruption of the Pulmonary Artery No abstract available

Proximal Interruption of the Pulmonary Artery No abstract available