Thoracic Imaging

Visually Estimated RESOLVE Score Based on Coronary Computed Tomography to Predict Side Branch Occlusion in Percutaneous Bifurcation Intervention Purpose: The quantitative RESOLVE (Risk prEdiction of Side branch OccLusion in coronary bifurcation interVEntion) score derived from coronary computed tomography angiography (coronary CTA) was developed as a noninvasive and accurate prediction tool for side branch (SB) occlusion in coronary bifurcation intervention. We aimed to determine the ability of a visually estimated CTA-derived RESOLVE score (V-RESOLVE score) to predict SB occlusion in coronary bifurcation intervention. Materials and Methods: The present study included 363 patients with 400 bifurcation lesions. CTA-derived V-RESOLVE score was derived and compared with the quantitative CTA-derived RESOLVE score. The scoring systems were divided into quartiles, and classified as the high-risk and non–high-risk groups. SB occlusion was defined as any decrease in thrombolysis in myocardial infarction flow grade after main vessel stenting. Results: In total, 28 SB occlusions (7%) occurred. The concordance between visual and quantitative CTA analysis showed poor to excellent agreement (weighted κ range: 0.099 to 0.867). The area under the receiver operating curve for the prediction of SB occlusion was significantly higher for the CTA-derived V-RESOLVE score than for quantitative CTA-derived RESOLVE score (0.792 vs. 0.709, P=0.049). The total net reclassification index was 42.7% (P=0.006), and CTA-derived V-RESOLVE score showed similar capability to discriminate between high-risk group (18.6% vs. 13.8%, P=0.384) and non–high-risk group (3.8% vs. 4.9%, P=0.510) as compared with quantitative CTA-derived RESOLVE score. Conclusions: Visually estimated CTA-derived V-RESOLVE score is an accurate and easy-to-use prediction tool for the stratification of SB occlusion in coronary bifurcation intervention. A.M.M., and K.G. contributed equally to this work. This study was supported by a statutory grant of the National Institute of Cardiology in Warsaw (ID: 2.43/III/16). The authors declare no conflicts of interest. Correspondence to: Maksymilian P. Opolski, MD, Department of Interventional Cardiology and Angiology, National Institute of Cardiology, Alpejska 42, Warsaw 04-628, Poland (e-mail: opolski.mp@gmail.com). Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved

Review of Technical Advancements and Clinical Applications of Photon-counting Computed Tomography in Imaging of the Thorax Photon-counting computed tomography (CT) is a developing technology that has the potential to address some limitations of CT imaging and bring about improvements and potentially new applications to this field. Photon-counting detectors have a fundamentally different detection mechanism from conventional CT energy-integrating detectors that can improve dose efficiency, spatial resolution, and energy-discrimination capabilities. In the past decade, promising human studies have been reported in the literature that have demonstrated benefits of this relatively new technology for various clinical applications. In this review, we provide a succinct description of the photon-counting detector technology and its detection mechanism in comparison with energy-integrating detectors in a manner understandable for clinicians and radiologists, introduce benefits and some of the existing challenges present in this technology, and provide an overview of the current status and potential clinical applications of this technology in imaging of the thorax by providing example images acquired with an investigational whole-body photon-counting CT scanner. This work was originated at: National Institutes of Health (NIH), 9000 Rockville Pike, Bethesda, MD 20892, 301-496-4000, TTY 301-402-9612. This research was supported, in part, by the Intramural Research Program of the National Institutes of Health Clinical Center. The National Institutes of Health and Siemens Medical Solutions have a Cooperative Research and Development Agreement providing financial and material support including the photon-counting CT system. Authors unaffiliated with Siemens had full control over data and information presented in this paper. The clinical images were acquired under a protocol approved by the Institutional Review Board using an investigational photon-counting computed tomography system. The authors declare no conflicts of interest. Correspondence to: Marcus Y. Chen, MD, National Heart, Lung and Blood Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892 (e-mail: marcus.chen@nih.gov). Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved

Early Left Ventricular Diastolic Dysfunction and Abnormal Left Ventricular-left Atrial Coupling in Asymptomatic Patients With Hypertension: A Cardiovascular Magnetic Resonance Feature Tracking Study Purpose: Hypertension (HTN) patients suffer from increased risk of left ventricular (LV) diastolic dysfunction and LV hypertrophy (LVH). Evaluation of early LV diastolic function requires accurate noninvasive diagnostic tools. The aim of this study was to evaluate whether cardiovascular magnetic resonance feature-tracking (CMR-FT) could detect early LV dysfunction and evaluate LV-left atrium (LA) correlation in HTN patients. Materials and Methods: In all, 89 HTN patients and 38 age-matched and sex-matched controls were retrospectively enrolled and underwent CMR examination. HTN patients were divided into LVH (n=38) and non-LVH (n=51) groups. All LV deformation parameters were analyzed in radial, circumferential, and longitudinal directions, including peak strain, peak systolic strain rate and peak diastolic strain rate (PDSR), LA strain and strain rate (SR), including LA reservoir function (εs, SRs), conduit function (εe, SRe), and booster pump function (εa, SRa). Results: Compared with controls, the LV PDSR in radial, circumferential, and longitudinal directions and the LA reservoir and conduit function were significantly impaired in HTN patients regardless of LVH (all P<0.05). LV longitudinal and radial PDSR were correlated with LA reservoir and conduit function (all P<0.01). Among all LV and LA impaired deformation parameters, the longitudinal PDSR (in LV) and εe (in LA) were the most sensitive parameter for the discrimination between non-LVH and healthy volunteers, with an area under the curve of 0.70 (specificity 79%, sensitivity 55%) and 0.76 (specificity 95%, sensitivity 49%), respectively. The area under the curve reached 0.81 (specificity 82%, sensitivity 75%) combined with the longitudinal PDSR and εe. Conclusion: CMR-FT could detect early LV diastolic dysfunction in HTN patients, which might be associated with LA reservoir and conduit dysfunction. S.Z. and J.C. contributed equally to this work and should be considered co-corresponding authors. The study was supported by grant No. 81930044 and No. 81620108015 from the key projects of National Natural Science Foundation of China. The authors declare no conflicts of interest. Correspondence to: Shihua Zhao, MD, MR Center, Fuwai Hospital, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases of China, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China (e-mail: cjrzhaoshihua2009@163.com). Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved

Assessment of Intramyocardial Fat Content Using Computed Tomography: Is There a Relationship With Obesity? Background: Fat deposition in the liver and the skeletal muscle are linked to cardiovascular risk factors. Fat content in tissues can be estimated by measuring attenuation on noncontrast computed tomography (CT). Quantifying intramyocardial fat content is of interest as it may be related to myocardial dysfunction or development of heart failure. We hypothesized that myocardial fat content would correlate with severity of obesity, liver fat, and components of the metabolic syndrome. Methods: We measured attenuation values on 121 noncontrast CT scans from the spleen, liver, erector spinae muscle, and myocardial septum. A chart review was performed for patient demographics and clinical characteristics. We tested for correlations between attenuation values in each of the tissues and various clinical parameters. Results: We studied 78 females and 43 males, with a mean age of 54.5±11.2 years. Weak, but significant inverse Spearman correlation between body mass index and attenuation values were found in the liver (ρ=−0.228, P=0.012), spleen (ρ=−0.225, P=0.017), and erector spinae muscle (ρ=−0.211, P=0.022) but not in the myocardial septum (ρ=0.012, P=0.897). Mean attenuation in the nonobese group versus obese group (body mass index >30 kg/m2) were 41.1±5.0 versus 42.3±6.9 (P=0.270) in myocardial septum, 56.1±8.7 versus 51.7±10.9 (P=0.016) in the liver, 43.9±8.9 versus 40.1±10.4 (P=0.043) in the spleen, and 41.7±8.3 versus 39.0±8.8 (P=0.087) in the erector spinae muscle. Conclusions: Although CT is a theoretically appealing modality to assess fat content of the myocardium, we did not find a relationship between myocardial CT attenuation and obesity, or other cardiovascular risk factors. These findings suggest that the degree of myocardial fat accumulation in obesity or metabolic syndrome is too small to be detected with this modality. U.J.S. has received institutional research support and/or honoraria for speaking and consulting from Astellas, Bayer, Bracco, Elucid BioImaging, General Electric, Guerbet, HeartFlow Inc., and Siemens Healthineers. The remaining authors declare no conflicts of interest. Correspondence to: Sheldon E. Litwin, MD, 114 Doughty Street, Charleston, SC 29425 (e-mail: litwins@musc.edu). Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved

Computed Tomography-based Lung Residual Volume and Mortality of Patients With Coronavirus Disease-19 (COVID-19) Rationale and Objectives: To assess the effect of computed tomography (CT)-based residual lung volume (RLV) on mortality of patients with coronavirus disease 2019 (COVID-19). Materials and Methods: A single-center, retrospective study of a prospectively maintained database was performed. In total, 138 patients with COVID-19 were enrolled. Baseline chest CT scan was performed in all patients. CT-based automated and semi-automated lung segmentation was performed using the Alma Medical workstation to calculate normal lung volume, lung opacities volume, total lung volume, and RLV. The primary end point of the study was mortality. Univariate and multivariate analyses were performed to determine independent predictors of mortality. Results: Overall, 84 men (61%) and 54 women (39%) with a mean age of 47.3 years (±14.3 y) were included in the study. Overall mortality rate was 21% (29 patients) at a median time of 7 days (interquartile range, 4 to 11 d). Univariate analysis demonstrated that age, hypertension, and diabetes were associated with death (P<0.01). Similarly, patients who died had lower normal lung volume and RLV than patients who survived (P<0.01). Multivariate analysis demonstrated that low RLV was the only independent predictor of death (odds ratio, 1.042; 95% confidence interval, 10.2-10.65). Furthermore, receiver operating characteristic curve analysis demonstrated that a RLV ≤64% significantly increased the risk of death (odds ratio, 4.8; 95% confidence interval, 1.9-11.7). Conclusion: Overall mortality of patients with COVID-19 may reach 21%. Univariate and multivariate analyses demonstrated that reduced RLV was the principal independent predictor of death. Furthermore, RLV ≤64% is associated with a 4-fold increase on the risk of death. Present address: David Ernesto Timaran-Montenegro, MD, MSCS, Felix Cuevas 540, Col del Valle Sur, Benito Juarez, Ciudad de Mexico 03100, Mexico. The authors declare no conflicts of interest. Correspondence to: David Ernesto Timaran-Montenegro, MD, MSCS, National Medical Center "20 de Noviembre", National Autonomous University of Mexico (UNAM), Mexico City, Mexico 03229 (e-mail: david_timaran@yahoo.com). Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved

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 © 2021 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 © 2021 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 © 2021 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 © 2021 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 © 2021 Wolters Kluwer Health, Inc. All rights reserved

 

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