Thoracic Imaging

Quantitative Differentiation of Left Atrial Performance in Hypertrophic Cardiomyopathy: Comparison Between Nonobstruction and Occult Obstruction With 4-dimensional Volume-strain Objective: The objective of this study was to describe the different components of left atrial (LA) dysfunction predictors in nonobstructive and occult obstructive hypertrophy cardiomyopathy (HCM) patients especially with preserved left ventricular (LV) ejection fraction, particularly using LA 4-dimensional (D) longitudinal and circumferential strains. Methods: Twenty-eight nonobstructive HCM patients and 30 occult obstructive HCM patients according to LV outflow tract gradient at rest and after exercise were prospectively enrolled. 4D echocardiographic evaluation was performed in 58 HCM patients, both nonobstructive and occult obstructive, and 38 control subjects. LA reservoir, conduit, contractile functions were performed by 4D volume-strain with volumes and longitudinal, circumferential strains. Results: Optimal correlation coefficients obtained between LV 4D mass (index) and LA 4D longitudinal/circumferential strain (r=−0.860 to 0.518, all P<0.001). Both nonobstructive and occult obstructive HCM patients had increased volumes and significantly decreased longitudinal, circumferential strain values with lower reservoir, conduit, contractile functions than the controls (all P<0.001). Occult obstructive HCM patients presented incremented volumes compared with nonobstructive ones (P<0.001 to 0.003). Lower conduit function and higher contractile function indicated with lower reservoir function revealed by circumferential strain in occult obstructive HCM patients than nonobstructive ones (P<0.001 to 0.017). Interclass correlation coefficients of intraobserver and interobserver in the LV and LA 4D value evaluations were >0.75 and >0.85, respectively. Conclusions: LA volumes were significantly increased and LA reservoir, conduit, and contractile functions were significantly impaired in HCM patients. Furthermore, different performances of LA functional analyses in nonobstruction and occult obstruction patients with 4D volume-strain echocardiography may facilitate the recognition of subtle LA dysfunctional differentiation in HCM patients. M.S. is a co-first author and contributed equally as H.R. The research protocol was approved by the regional ethics committee, and all included patients provided written informed consent. H.R.: was involved in compilation of the data collected, drafting, and writing the manuscript. M.S. and P.-y.Z.: were the supervisors responsible for echocardiography and revision of the manuscript. L.-l.W., J.-y.R., and X.-w.M.: assisted in the measurement and monitoring the patients' examination. Supported by Nanjing Medical Science and Technique Development Foundation 2017(8). The authors declare no conflict of interest. Correspondence to: Ping-yang Zhang, MD, PhD, Department of Echocardiography, Nanjing First Hospital, Nanjing Medical University, Changle Road 68, Nanjing 210006, Jiangsu Province, China (e-mail: zhpy28@hotmail.com). This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0/ Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved

Cardiac Magnetic Resonance Imaging in Coronavirus Disease 2019 (COVID-19): A Systematic Review of Cardiac Magnetic Resonance Imaging Findings in 199 Patients Objective: Cardiac magnetic resonance imaging (CMR) with its new quantitative mapping techniques has proved to be an essential diagnostic tool for detecting myocardial injury associated with coronavirus disease 2019 (COVID-19) infection. This systematic review sought to assess the important imaging features on CMR in patients diagnosed with COVID-19. Materials and Methods: We performed a systematic literature review within the PubMed, Embase, Google Scholar, and WHO databases for articles describing the CMR findings in COVID-19 patients. Results: A total of 34 studies comprising 199 patients were included in the final qualitative synthesis. Of the CMRs 21% were normal. Myocarditis (40.2%) was the most prevalent diagnosis. T1 (109/150; 73%) and T2 (91/144; 63%) mapping abnormalities, edema on T2/STIR (46/90; 51%), and late gadolinium enhancement (LGE) (85/199; 43%) were the most common imaging findings. Perfusion deficits (18/21; 85%) and extracellular volume mapping abnormalities (21/40; 52%), pericardial effusion (43/175; 24%), and pericardial LGE (22/100; 22%) were also seen. LGE was most commonly seen in the subepicardial location (81%) and in the basal-mid part of the left ventricle in inferior segments. In most of the patients, ventricular functions were normal. Kawasaki-like involvement with myocardial edema without necrosis/LGE (4/6; 67%) was seen in children. Conclusion: CMR is useful in assessing the prevalence, mechanism, and extent of myocardial injury in COVID-19 patients. Myocarditis is the most common imaging diagnosis, with the common imaging findings being mapping abnormalities and myocardial edema on T2, followed by LGE. As cardiovascular involvement is associated with poor prognosis, its detection warrants prompt attention and appropriate treatment. The authors declare no conflicts of interest. Correspondence to: Sanjiv Sharma, MD, Department of Cardiovascular Radiology & Endovascular Interventions, All India Institute of Medical Sciences, New Delhi 110029, India (e-mail: meetisv@yahoo.com). Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved

Smooth Muscle Conditions of the Chest: A Clinical, Radiologic, and Pathologic Review Smooth muscle conditions of the chest have diverse clinical and imaging manifestations and may involve nearly every thoracic structure. Differentiation among these conditions requires the integration of clinical, radiologic, and histopathologic data. Histologic examination in conjunction with immunohistochemistry is essential for differentiation from other spindle cell neoplastic mimics. Familiarity with these entities will ensure the inclusion of smooth muscle conditions in the differential diagnosis of thoracic soft tissue lesions and potentially guide the clinician in appropriate management. We review the clinical, imaging, and histopathologic features of thoracic smooth muscle-related conditions organized by the anatomic structures affected. The authors declare no conflicts of interest. Correspondence to: Justin T. Stowell, MD, Department of Radiology, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224 (e-mail: stowell.justin@mayo.edu). Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved

Influence of Asthma Onset on Airway Dimensions on Ultra–high-resolution Computed Tomography in Chronic Obstructive Pulmonary Disease Purpose: Asthma onset before the age of 40 years is associated with distinct clinical manifestations in chronic obstructive pulmonary disease (COPD) patients, but its morphologic features remain unestablished. This study aimed to explore airway morphology in COPD patients with asthma onset before 40 years of age using ultra–high-resolution computed tomography (U-HRCT), which allows a more accurate quantitation of the lumen and the wall in smaller airways than using conventional CT. Materials and Methods: Clinical data of 500 consecutive patients undergoing full inspiratory U-HRCT (1024×1024 matrix and 0.25 mm slice thickness) were retrospectively analyzed. COPD patients without asthma, COPD patients with asthma onset at age below or 40 years and above, and non-COPD smoker controls (N=137, 29, 34, and 22, respectively) were enrolled. The length, lumen area (LA), wall thickness and area (WA), and wall area percent (WA%) of the segmental (third-generation) to sub-subsegmental (fifth-generation) bronchus and the low attenuation volume percent (LAV%) were measured. Results: LA and WA were smaller in the fourth and fifth generation in COPD patients than in non-COPD controls, regardless of the age of asthma onset. LA was smaller and WA% was larger in the fourth-generation and fifth-generation airways in COPD with asthma onset before 40 years than COPD without asthma, whereas WA did not differ between them. In multivariate analyses, asthma onset before 40 years was associated with smaller LA in COPD patients independent of demographics, use of inhaled corticosteroids and long-acting bronchodilators, airflow limitation, and LAV%. Conclusions: Asthma onset before 40 years of age could be associated with greater lumen narrowing of the airways in COPD. This study was partially supported by the Japan Society for the Promotion of Science (JSPS) [Grants-in-Aid for Scientific Research 19K08624]. N.T., S.S, T.O., and T.H. were supported by a grant from FUJIFILM Co., Ltd. K.T. was supported by Canon Medical Systems Corporation. None of these companies had a role in the design or analysis of the study or in the writing of the manuscript. The authors declare no conflicts of interest. Correspondence to: Naoya Tanabe, MD, Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan (e-mail: ntana@kuhp.kyoto-u.ac.jp). Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved

Accessory and Incomplete Lung Fissures: Clinical and Histopathologic Implications Objective: This article reviews the anatomy, histology, and disease processes of pulmonary fissures, with emphasis on clinical implications of accessory and incomplete fissures. Conclusion: Accessory and incomplete pulmonary fissures are often overlooked during routine imaging but can have profound clinical importance. Knowledge of fissure anatomy could improve diagnostic accuracy and inform prognosis for oncologists, interventional pulmonologists, and thoracic surgeons. P.A.B.: primary manuscript author, retrieval and analysis of literature, design and production of tables, and editing and approval of the manuscript. R.A.G., G.M.L., and C.M.W.: data collection, critical review, and editing and approval of the manuscript. D.I.S.: pathologic data collection and analysis, pathologic slide preparation, literature analysis, and editing and approval of the manuscript. R.E.G.: critical review and editing and approval of the manuscript. M.D.G.: project supervision and editing and approval of the manuscript. M.L.: surgical data collection and analysis, surgical photography and video preparation, and editing and approval of the manuscript. J.T.S.: conception and design, senior manuscript author, study coordination, literature review; data collection and analysis, project oversight, and leadership. C.M.W. receives royalties from Amirsys and Elsevier. C.M.W. is a part of the speaker's bureau for Boehringer Ingelheim. The remaining authors declare no conflicts of interest. Correspondence to: Justin T. Stowell, MD, Department of Radiology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 (e-mail: stowell.justin@mayo.edu). Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved

Cardiovascular Risk Factors and Coronary Calcification in a Middle-aged Dutch Population: The ImaLife Study Purpose: To assess the presence of coronary artery calcium (CAC) and its association with cardiovascular risk factors and Systematic COronary Risk Evaluation (SCORE) risk in a middle-aged Dutch population. Methods: Classic cardiovascular risk factors and CAC were analyzed in 4083 participants aged 45 to 60 years (57.9% women) from the population-based ImaLife study. CAC scores were quantified on noncontrast cardiac CT scans. Age-specific and sex-specific distribution of CAC categories (0, 1 to 99, 100 to 299, ≥300) and percentiles were determined. SCORE risk categories (<1%, ≥1% to 5%, and ≥5%) were compared with CAC distribution. Population attributable fractions (PAFs) of classic risk factors for CAC were estimated. Results: CAC was present in 54.5% male and 26.5% female participants. The percentage of individuals with CAC increased with increasing age. Mean SCORE was 2.0% in men and 0.7% in women. In SCORE <1%, 32.7% of men and 17.1% of women had CAC. In men with SCORE ≥5%, 26.9% had no CAC. Only 0.1% of women had SCORE ≥5%. PAF of classic risk factors for CAC was 18.5% in men and 31.4% in women. PAF was highest for hypertension (in men 8.0%, 95% confidence interval, 4.2%-11.8%; in women 13.1%, 95% confidence interval, 7.9%-18.2%) followed by hypercholesterolemia and obesity. Conclusion: In this middle-aged cohort, more than half of the men and a quarter of the women had CAC. One out of 4 men at high risk (SCORE ≥5%) could be placed into a lower risk category owing to absence of CAC. Thus, adding CAC scoring to SCORE could have considerable effect on cardiovascular risk classification. Elimination of exposure to classic risk factors could reduce limited proportion of CAC in a middle-aged population. The PhD project of Congying Xia is part of the ImaLife project, which is funded by an institutional research grant from Siemens Healthineers and by the Ministry of Economic Affairs and Climate Policy by means of the PPP Allowance made available by the Top Sector Life Sciences & Health to stimulate public-private partnerships. M.O. is involved in the company iDNA BV. The authors declare no conflicts of interest. Correspondence to: Rozemarijn Vliegenthart, MD, PhD, Department of Radiology, University Medical Center Groningen, EB44, Hanzeplein 1, Groningen, 9713 GZ, The Netherlands (e-mail: r.vliegenthart@umcg.nl). This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0/ Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved

Prevalence of Abnormal Coronary Findings on Coronary Computed Tomography Angiography Among Young Adults Presenting With Chest Pain Purpose: We evaluated the prevalence of coronary stenosis on coronary computed tomography angiography (CCTA) in patients aged 18 to 30 years, who presented to the emergency department with chest pain. We also examined the risk factors potentially associated with abnormal coronary findings on CCTA in this age group. Materials and Methods: A total of 884 patients were retrospectively evaluated. Indication for CCTA was guided by our hospital's chest pain protocol based on ACC/AHA guidelines. These were performed using the standard technique and interpreted based on CAD-RADS guidelines. Scans were identified as abnormal if atherosclerotic coronary artery disease (CAD), myocardial bridging (MB), or any anatomic coronary artery anomaly were present. Results: Twenty-two percent of patients had a coronary abnormality on CCTA. The most common abnormality was MB (17.3%), followed by CAD (4.4%) and coronary anomalies (1.5%). A small minority had stenosis (2.8%), most commonly caused by CAD. Most cases with stenosis were minimal to mild (72%) with 0.8% having coronary stenosis ≥50%. Age and male sex were risk factors for both coronary artery stenosis (odds ratio: 1.32 and 4.50, 95% confidence interval: 1.03-1.69, and 1.23-16.46, P=0.028 and 0.023, respectively) and CAD (odds ratio: 1.52 and 3.67, 95% confidence interval: 1.14-2.04, and 1.26-10.66, P=0.005 and 0.017, respectively). Conclusions: Epicardial coronary stenosis is rarely the cause of chest pain among young adult patients presenting to the emergency department. Age and male sex were both risk factors for coronary artery stenosis/disease in this age group. J.R.B.: concept, design, data collection, writing and editing manuscript, submission for publication. M.C.O.: concept, design, data collection. B.Y. and J.C.: writing and editing manuscript, statistical analysis. M.K., J.W., M.K., and A.A.: writing and editing manuscript. M.S., M.H., and A.G.: data collection. N.F.: data collection, writing and editing manuscript. C.W.: writing and editing manuscript, submission for publication. B.L.: concept, design, data collection, writing and editing manuscript. The authors declare no conflicts of interest. Correspondence to: Jeremy R. Burt, MD, Department of Radiology, MUSC, 96 Jonathan Lucas Street, MSC 323, Clinical Science Building, Room 210, Charleston, SC 29425 (e-mail: burtje@musc.edu). Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved

Blastomycosis: The Great Pretender Blastomycosis is an endemic fungal infection caused by Blastomyces, a soil-dwelling dimorphic fungus found predominantly in North America. In this pictorial essay, we illustrate the varied imaging features of blastomycosis along with a brief description of the epidemiology, clinical aspects, and differential diagnosis, emphasizing clues that can help radiologists arrive at this diagnosis. The authors declare no conflicts of interest. Correspondence to: Jeffrey P. Kanne, MD, Department of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue MC 3252, Madison, WI 53792-3252 (e-mail: jkanne@uwhealth.org). Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved

Differentiating Nonischemic Dilated Cardiomyopathy With Incidental Infarction From Ischemic Cardiomyopathy by Geometric Indices Derived From Cardiovascular Magnetic Resonance Purpose: The purpose of this study was to differentiate nonischemic dilated cardiomyopathy with incidental myocardial infarction (NICM with incidental MI) from ischemic cardiomyopathy (ICM) by integrating left ventricular (LV) geometric indices and ischemic late gadolinium enhancement (LGE), obtained from cardiac magnetic resonance (CMR) imaging. Materials and Methods: All subjects were studied on a 1.5 Tesla magnetic resonance imaging scanner. All patients had an LV ejection fraction (LVEF) <50% with LV dilation. LV end-diastolic volume (LVEDV), LVEDV index (LVEDVi), LVEF, the number and distribution of ischemic LGE segments, and ratios of volumetric and functional indices to ischemic LGE segments were determined. Logistic regression was used to detect the independent predictor of ICM. Receiver operating characteristic analysis differentiated NICM with incidental MI from ICM. Results: Of a total of 63 patients enrolled, 45 patients had ICM, and 18 patients had NICM with incidental MI. Both groups had similar LVEF. Compared with ICM, NICM with incidental MI had more LV dilation, whereas ICM had more ischemic LGE segments. A higher number of ischamic LGE segments remained an independent predictor of ICM (odds ratio: 18.2, 95% confidence interval: 1.64-201.34, P=0.018). The optimal cut-off value for detecting NICM with incidental MI is the ratio of LVEDVi to the number of ischemic LGE segments over 25 mL/m2/segment (sensitivity 100%, specificity 91%, P<0.0001). Conclusion: Patients with NICM with incidental MI can be reliably distinguished from ICM using the ratio of LVEDVi divided by the number of ischemic LGE segments. This technique may improve diagnosis and help aid management of patients with cardiomyopathy and coexistent coronary artery disease. The authors declare no conflicts of interest. Correspondence to: Shihua Zhao, MD, FESC, Fuwai Hospital, No. 167 Beilishi Road, Beijing 100037, China (e-mail: cjrzhaoshihua2009@163.com). Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved

Radiologic Manifestations of Pulmonary Vein Ablation Complications: A Pictorial Review In patients with atrial fibrillation refractory to drug therapy and cardioversion, pulmonary vein ablation is an alternative treatment that eradicates arrhythmogenic activity originating in the muscles of the pulmonary veins. While this procedure has a low incidence of significant complications, iatrogenic injuries are possible. Through multimodality pictorial examples utilizing computed tomography, nuclear medicine, fluoroscopy, and chest radiographs, the complications associated with pulmonary vein ablation will be reviewed. Examples of pulmonary vein stenosis, right phrenic nerve injury with associated diaphragmatic paralysis, atrioesophageal fistula, and pericardioesophageal fistula will be illustrated. The authors declare no conflicts of interest. Correspondence to: Daniel T. Myers, MD, Department of Radiology, Henry Ford Hospital, 2799 West Grand Boulevard, Detroit, MI 48202 (e-mail: danielm@rad.hfh.edu). Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved

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