Publications by authors named "Mark L Schiebler"

83 Publications

Pulmonary Functional Imaging: Part 2-State-of-the-Art Clinical Applications and Opportunities for Improved Patient Care.

Radiology 2021 Apr 13:204033. Epub 2021 Apr 13.

From the Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, South Korea (K.S.L.); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wis (M.L.S.); Departments of Medicine and Medical Biophysics, Robarts Research Institute, Western University, London, Canada (G.P.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Radiology and Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan (Y.O.); and Center for Pulmonary Functional Imaging, Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.).

Pulmonary functional imaging may be defined as the regional quantification of lung function by using primarily CT, MRI, and nuclear medicine techniques. The distribution of pulmonary physiologic parameters, including ventilation, perfusion, gas exchange, and biomechanics, can be noninvasively mapped and measured throughout the lungs. This information is not accessible by using conventional pulmonary function tests, which measure total lung function without viewing the regional distribution. The latter is important because of the heterogeneous distribution of virtually all lung disorders. Moreover, techniques such as hyperpolarized xenon 129 and helium 3 MRI can probe lung physiologic structure and microstructure at the level of the alveolar-air and alveolar-red blood cell interface, which is well beyond the spatial resolution of other clinical methods. The opportunities, challenges, and current stage of clinical deployment of pulmonary functional imaging are reviewed, including applications to chronic obstructive pulmonary disease, asthma, interstitial lung disease, pulmonary embolism, and pulmonary hypertension. Among the challenges to the deployment of pulmonary functional imaging in routine clinical practice are the need for further validation, establishment of normal values, standardization of imaging acquisition and analysis, and evidence of patient outcomes benefit. When these challenges are addressed, it is anticipated that pulmonary functional imaging will have an expanding role in the evaluation and management of patients with lung disease.
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http://dx.doi.org/10.1148/radiol.2021204033DOI Listing
April 2021

Pulmonary Functional Imaging: Part 1-State-of-the-Art Technical and Physiologic Underpinnings.

Radiology 2021 Apr 6:203711. Epub 2021 Apr 6.

From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.).

Over the past few decades, pulmonary imaging technologies have advanced from chest radiography and nuclear medicine methods to high-spatial-resolution or low-dose chest CT and MRI. It is currently possible to identify and measure pulmonary pathologic changes before these are obvious even to patients or depicted on conventional morphologic images. Here, key technological advances are described, including multiparametric CT image processing methods, inhaled hyperpolarized and fluorinated gas MRI, and four-dimensional free-breathing CT and MRI methods to measure regional ventilation, perfusion, gas exchange, and biomechanics. The basic anatomic and physiologic underpinnings of these pulmonary functional imaging techniques are explained. In addition, advances in image analysis and computational and artificial intelligence (machine learning) methods pertinent to functional lung imaging are discussed. The clinical applications of pulmonary functional imaging, including both the opportunities and challenges for clinical translation and deployment, will be discussed in part 2 of this review. Given the technical advances in these sophisticated imaging methods and the wealth of information they can provide, it is anticipated that pulmonary functional imaging will be increasingly used in the care of patients with lung disease. © RSNA, 2021
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http://dx.doi.org/10.1148/radiol.2021203711DOI Listing
April 2021

Evaluation for Myocarditis in Competitive Student Athletes Recovering From Coronavirus Disease 2019 With Cardiac Magnetic Resonance Imaging.

JAMA Cardiol 2021 Jan 14. Epub 2021 Jan 14.

Department of Radiology, University of Wisconsin, Madison.

Importance: The utility of cardiac magnetic resonance imaging (MRI) as a screening tool for myocarditis in competitive student athletes returning to training after recovering from coronavirus disease 2019 (COVID-19) infection is unknown.

Objective: To describe the prevalence and severity of cardiac MRI findings of myocarditis in a population of competitive student athletes recovering from COVID-19.

Design, Setting, And Participants: In this case series, an electronic health record search was performed at our institution (University of Wisconsin) to identify all competitive athletes (a consecutive sample) recovering from COVID-19, who underwent gadolinium-enhanced cardiac MRI between January 1, 2020, and November 29, 2020. The MRI findings were reviewed by 2 radiologists experienced in cardiac imaging, using the updated Lake Louise criteria. Serum markers of myocardial injury and inflammation (troponin-I, B-type natriuretic peptide, C-reactive protein, and erythrocyte sedimentation rate), an electrocardiogram, transthoracic echocardiography, and relevant clinical data were obtained.

Exposures: COVID-19 infection, confirmed using reverse transcription-polymerase chain reaction testing.

Main Outcomes And Measures: Prevalence and severity of MRI findings consistent with myocarditis among young competitive athletes recovering from COVID-19.

Results: A total of 145 competitive student athletes (108 male and 37 female individuals; mean age, 20 years; range, 17-23 years) recovering from COVID-19 were included. Most patients had mild (71 [49.0%]) or moderate (40 [27.6%]) symptoms during the acute infection or were asymptomatic (24 [16.6%]). Symptoms were not specified or documented in 10 patients (6.9%). No patients required hospitalization. Cardiac MRIs were performed a median of 15 days (range, 11-194 days) after patients tested positive for COVID-19. Two patients had MRI findings consistent with myocarditis (1.4% [95% CI, 0.4%-4.9%]). Of these, 1 patient had marked nonischemic late gadolinium enhancement and T2-weighted signal abnormalities over multiple segments, along with an abnormal serum troponin-I level; the second patient had 1-cm nonischemic mild late gadolinium enhancement and mild T2-weighted signal abnormalities, with normal laboratory values.

Conclusions And Relevance: In this case series study, based on MRI findings, there was a low prevalence of myocarditis (1.4%) among student athletes recovering from COVID-19 with no or mild to moderate symptoms. Thus, the utility of cardiac MRI as a screening tool for myocarditis in this patient population is questionable.
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http://dx.doi.org/10.1001/jamacardio.2020.7444DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7809616PMC
January 2021

Imaging of pulmonary hypertension in adults: a position paper from the Fleischner Society.

Eur Respir J 2021 Jan 5;57(1). Epub 2021 Jan 5.

Université Paris Saclay, Inserm UMR S999, Dept of Pneumology, AP-HP, Pulmonary Hypertension Reference Center, Hôpital de Bicêtre, Le Kremlin Bicêtre, France.

Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mmHg and classified into five different groups sharing similar pathophysiologic mechanisms, haemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was formed from within the Fleischner Society based on expertise in the imaging and/or management of patients with PH, as well as experience with methodologies of systematic reviews. The working group identified key questions focusing on the utility of CT, MRI, and nuclear medicine in the evaluation of PH: Is noninvasive imaging capable of identifying PH? What is the role of imaging in establishing the cause of PH? How does imaging determine the severity and complications of PH? How should imaging be used to assess chronic thromboembolic PH before treatment? Should imaging be performed after treatment of PH? This systematic review and position paper highlights the key role of imaging in the recognition, work-up, treatment planning, and follow-up of PH.
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http://dx.doi.org/10.1183/13993003.04455-2020DOI Listing
January 2021

Imaging of Pulmonary Hypertension in Adults: A Position Paper from the Fleischner Society.

Radiology 2021 Mar 5;298(3):531-549. Epub 2021 Jan 5.

From the Department of Thoracic Imaging, Hôpital Calmette, Boulevard Jules Leclercq, 59037 Lille, France (M.R.J.); Department of Medicine, University of British Columbia and Centre for Heart Lung Innovation, St Paul's Hospital, Vancouver, Canada (C.J.R.); Department of Radiology, UW-Madison School of Medicine and Public Health, Madison, Wis (M.L.S.); Department of Radiology, Stanford University Medical Center, Stanford, Calif (A.N.C.L.); Division of Imaging, Department of Infection Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, England (J.M.W.); Department of Respiratory Medicine, Hannover Medical School and German Centre of Lung Research (DZL), Hannover, Germany (M.M.H.); Department of Radiology, Saint Louis University School of Medicine, St Louis, Mo (P.O.A.); Department of Radiology, Medical College of Wisconsin, Milwaukee, Wis (L.R.G.); Department of Radiology, Vancouver General Hospital, Vancouver, Canada (J.M.); Department of Radiology and Medicine, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY (L.B.H.); Department of Radiology, Fujita Health University School of Medicine, Toyoake, Japan (Y.O.); Division of Cardiothoracic Surgery, University of California, San Diego, La Jolla, Calif (P.T.); Edinburgh Imaging, Queens Medical Research Institute, University of Edinburgh, Edinburgh, Scotland (E.J.R.v.B.); Department of Library and Knowledge Services (S.L.K.) and Department of Radiology (D.A.L.), National Jewish Health, Denver, Colo; Department of Radiology, Duke University School of Medicine, Durham, NC (G.D.R.); and Université Paris Saclay, Inserm UMR S999, Department of Pneumology, AP-HP, Pulmonary Hypertension Reference Center, Hôpital de Bicêtre, Le Kremlin Bicêtre, France (M.H.).

Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mm Hg and classified into five different groups sharing similar pathophysiologic mechanisms, hemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was formed from within the Fleischner Society based on expertise in the imaging and/or management of patients with PH, as well as experience with methodologies of systematic reviews. The working group identified key questions focusing on the utility of CT, MRI, and nuclear medicine in the evaluation of PH: Is noninvasive imaging capable of identifying PH? What is the role of imaging in establishing the cause of PH? How does imaging determine the severity and complications of PH? How should imaging be used to assess chronic thromboembolic PH before treatment? Should imaging be performed after treatment of PH? This systematic review and position paper highlights the key role of imaging in the recognition, work-up, treatment planning, and follow-up of PH. This article is a simultaneous joint publication in and . The articles are identical except for stylistic changes in keeping with each journal's style. Either version may be used in citing this article. © 2021 RSNA and the European Respiratory Society.
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http://dx.doi.org/10.1148/radiol.2020203108DOI Listing
March 2021

Mucus Plugs and Emphysema in the Pathophysiology of Airflow Obstruction and Hypoxemia in Smokers.

Am J Respir Crit Care Med 2021 Apr;203(8):957-968

Division of Pulmonary and Critical Care Medicine, Department of Medicine.

The relative roles of mucus plugs and emphysema in mechanisms of airflow limitation and hypoxemia in smokers with chronic obstructive pulmonary disease (COPD) are uncertain. To relate image-based measures of mucus plugs and emphysema to measures of airflow obstruction and oxygenation in patients with COPD. We analyzed computed tomographic (CT) lung images and lung function in participants in the Subpopulations and Intermediate Outcome Measures in COPD Study. Radiologists scored mucus plugs on CT lung images, and imaging software automatically quantified emphysema percentage. Unadjusted and adjusted relationships between mucus plug score, emphysema percentage, and lung function were determined using regression. Among 400 smokers, 229 (57%) had mucus plugs and 207 (52%) had emphysema, and subgroups could be identified with mucus-dominant and emphysema-dominant disease. Only 33% of smokers with high mucus plug scores had mucus symptoms. Mucus plug score and emphysema percentage were independently associated with lower values for FEV and peripheral oxygen saturation ( < 0.001). The relationships between mucus plug score and lung function outcomes were strongest in smokers with limited emphysema ( < 0.001). Compared with smokers with low mucus plug scores, those with high scores had worse COPD Assessment Test scores (17.4 ± 7.7 vs. 14.4 ± 13.3), more frequent annual exacerbations (0.75 ± 1.1 vs. 0.43 ± 0.85), and shorter 6-minute-walk distance (329 ± 115 vs. 392 ± 117 m) ( < 0.001). Symptomatically silent mucus plugs are highly prevalent in smokers and independently associate with lung function outcomes. These data provide rationale for targeting patients with mucus-high/emphysema-low COPD in clinical trials of mucoactive treatments.Clinical trial registered with www.clinicaltrials.gov (NCT01969344).
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http://dx.doi.org/10.1164/rccm.202006-2248OCDOI Listing
April 2021

The Framingham Heart Study: Populational CT-based phenotyping in the lungs and mediastinum.

Eur J Radiol Open 2020 11;7:100260. Epub 2020 Sep 11.

Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.

The Framingham Heart Study (FHS) is one of the largest and established longitudinal populational cohorts. CT cohorts of the FHS since 2002 provided a unique opportunity to assess non-cardiac thoracic imaging findings. This review deals with image-based phenotyping studies from recent major publications regarding interstitial lung abnormalities (ILAs), pulmonary cysts, emphysema, pulmonary nodules, pleural plaques, normal spectrum of the thymus, and anterior mediastinal masses, concluding with the discussion of future directions of FHS CT cohorts studies in the era of radiomics and artificial intelligence.
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http://dx.doi.org/10.1016/j.ejro.2020.100260DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7495061PMC
September 2020

Interobserver agreement for the direct and indirect signs of pulmonary embolism evaluated using contrast enhanced magnetic angiography.

Eur J Radiol Open 2020 10;7:100256. Epub 2020 Sep 10.

Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States.

Background: Accurate diagnosis of pulmonary embolism (PE) using contrast enhanced MRA (CE-MRA) requires awareness of both the direct and indirect findings of PE.

Purpose: To evaluate reader agreement of the direct and indirect findings of PE on CE-MRA.

Methods: We evaluated pulmonary artery diameter, right ventricle/left ventricle ratio, and clot/vessel lumen signal intensity ratio. Also, eight direct and eight indirect findings of PE were interpreted twice by two radiologists with different experience levels. The prevalence, and intra- and inter-reader agreement for the direct and indirect findings of PE were recorded. Statistical analysis of the measurements was assessed using intraclass correlation while Cohen's kappa test determined inter- and intra-reader agreement.

Results: We reviewed 66 positive CE-MRA exams, 10 of which cases were used for training. The largest PE for each of the remaining 56 cases (40 woman) were included in this analysis (38.9 ± 19.7 (mean age (years) ± S.D.)). The highest interobserver agreement for the direct findings were vessel cutoff (κ = 0.52, 95 % CI = (0.30, 0.74), p < .0001) and bright clot (κ = 0.51, 95 % CI = (0.26, 0.78), p = .0001). The highest interobserver agreement for the indirect findings were for atelectasis (κ = 0.67, 95 % CI = (0.49, 0.87), p < .0001), pleural effusions (κ = 0.56, 95 % CI = (0.32, 0.79), p = 0001) and blank slate sing (κ = 0.56, 95 % CI = (0.18, 0.94), p < .0001).

Conclusion: The indirect findings of atelectasis and pleural effusion had better interobserver reproducibility than the direct findings of vessel cutoff and bright clot. The intraobserver reproducibility of the direct and indirect findings is dependent on experience level.

Summary Statement: Using contrast enhanced magnetic resonance angiography for the diagnosis of pulmonary embolism, the indirect findings of atelectasis and pleural effusion had better interobserver reproducibility than the direct findings of vessel cutoff and bright clot.
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http://dx.doi.org/10.1016/j.ejro.2020.100256DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7494795PMC
September 2020

Diagnosis of Coronavirus Disease 2019 Pneumonia by Using Chest Radiography: Value of Artificial Intelligence.

Radiology 2021 02 24;298(2):E88-E97. Epub 2020 Sep 24.

From the Departments of Medical Physics (R.Z., X.T., C.Z., D.G., J.W.G., K.L., S.B.R., G.H.C.) and Radiology (M.L.S., J.W.G., K.L., S.B.R., G.H.C.), University of Wisconsin-Madison School of Medicine and Public Health, 1111 Highland Ave, Madison, WI 53705; and Department of Radiology, Henry Ford Health System, Detroit, Mich (Z.Q., N.B.B., T.K.S., J.D.N,).

Background Radiologists are proficient in differentiating between chest radiographs with and without symptoms of pneumonia but have found it more challenging to differentiate coronavirus disease 2019 (COVID-19) pneumonia from non-COVID-19 pneumonia on chest radiographs. Purpose To develop an artificial intelligence algorithm to differentiate COVID-19 pneumonia from other causes of abnormalities at chest radiography. Materials and Methods In this retrospective study, a deep neural network, CV19-Net, was trained, validated, and tested on chest radiographs in patients with and without COVID-19 pneumonia. For the chest radiographs positive for COVID-19, patients with reverse transcription polymerase chain reaction results positive for severe acute respiratory syndrome coronavirus 2 with findings positive for pneumonia between February 1, 2020, and May 30, 2020, were included. For the non-COVID-19 chest radiographs, patients with pneumonia who underwent chest radiography between October 1, 2019, and December 31, 2019, were included. Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were calculated to characterize diagnostic performance. To benchmark the performance of CV19-Net, a randomly sampled test data set composed of 500 chest radiographs in 500 patients was evaluated by the CV19-Net and three experienced thoracic radiologists. Results A total of 2060 patients (5806 chest radiographs; mean age, 62 years ± 16 [standard deviation]; 1059 men) with COVID-19 pneumonia and 3148 patients (5300 chest radiographs; mean age, 64 years ± 18; 1578 men) with non-COVID-19 pneumonia were included and split into training and validation and test data sets. For the test set, CV19-Net achieved an AUC of 0.92 (95% CI: 0.91, 0.93). This corresponded to a sensitivity of 88% (95% CI: 87, 89) and a specificity of 79% (95% CI: 77, 80) by using a high-sensitivity operating threshold, or a sensitivity of 78% (95% CI: 77, 79) and a specificity of 89% (95% CI: 88, 90) by using a high-specificity operating threshold. For the 500 sampled chest radiographs, CV19-Net achieved an AUC of 0.94 (95% CI: 0.93, 0.96) compared with an AUC of 0.85 (95% CI: 0.81, 0.88) achieved by radiologists. Conclusion CV19-Net was able to differentiate coronavirus disease 2019-related pneumonia from other types of pneumonia, with performance exceeding that of experienced thoracic radiologists. © RSNA, 2021
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http://dx.doi.org/10.1148/radiol.2020202944DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7841876PMC
February 2021

Synopsis from Expanding Applications of Pulmonary MRI in the Clinical Evaluation of Lung Disorders: Fleischner Society Position Paper.

Chest 2021 Feb 14;159(2):492-495. Epub 2020 Sep 14.

Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, Boston, MA. Electronic address:

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http://dx.doi.org/10.1016/j.chest.2020.09.075DOI Listing
February 2021

Expanding Applications of Pulmonary MRI in the Clinical Evaluation of Lung Disorders: Fleischner Society Position Paper.

Radiology 2020 Nov 1;297(2):286-301. Epub 2020 Sep 1.

From the Center for Pulmonary Functional Imaging, Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02115 (H.H.); Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, Boston, Mass (B.M.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, University of Missouri, Columbia, Mo (T.A.A.); Department of Radiology, National Jewish Health, Denver, Colo (D.A.L.); Department of Radiology, Vancouver General Hospital and University of British Colombia, Vancouver, Canada (J.R.M.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Section of Academic Radiology, University of Sheffield, Sheffield, England, United Kingdom (J.M.W.); Edinburgh Imaging, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, Scotland, United Kingdom (E.J.R.v.B.); Department of Radiology, UW Madison School of Medicine and Public Health, Madison, Wis (M.L.S.); and Diagnostic and Interventional Radiology, University Hospital Heidelberg, Translational Lung Research Center Heidelberg, member of the German Center of Lung Research, Heidelberg, Germany (H.U.K.).

Pulmonary MRI provides structural and quantitative functional images of the lungs without ionizing radiation, but it has had limited clinical use due to low signal intensity from the lung parenchyma. The lack of radiation makes pulmonary MRI an ideal modality for pediatric examinations, pregnant women, and patients requiring serial and longitudinal follow-up. Fortunately, recent MRI techniques, including ultrashort echo time and zero echo time, are expanding clinical opportunities for pulmonary MRI. With the use of multicoil parallel acquisitions and acceleration methods, these techniques make pulmonary MRI practical for evaluating lung parenchymal and pulmonary vascular diseases. The purpose of this Fleischner Society position paper is to familiarize radiologists and other interested clinicians with these advances in pulmonary MRI and to stratify the Society recommendations for the clinical use of pulmonary MRI into three categories: suggested for current clinical use, promising but requiring further validation or regulatory approval, and appropriate for research investigations. This position paper also provides recommendations for vendors and infrastructure, identifies methods for hypothesis-driven research, and suggests opportunities for prospective, randomized multicenter trials to investigate and validate lung MRI methods.
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http://dx.doi.org/10.1148/radiol.2020201138DOI Listing
November 2020

Hyperpolarized Noble Gas Ventilation MRI in COPD.

Radiology 2020 10 11;297(1):211-213. Epub 2020 Aug 11.

From the Departments of Radiology (M.L.S.) and Medical Physics (S.F.), School of Medicine and Public Health, University of Wisconsin-Madison, 600 Highland Ave, Madison, WI 53792.

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http://dx.doi.org/10.1148/radiol.2020202855DOI Listing
October 2020

Vascular imaging of the lung: perspectives on current imaging methods.

Br J Radiol 2020 Aug 14:20200759. Epub 2020 Aug 14.

SINAPSE Chair of Clinical Radiology, Director Edinburgh Imaging facility QMRI, Honorary Consultant Radiologist, NHS Lothian Health Board, CO.19 Edinburgh Imaging, Queen's Medical Research Institute, Edinburgh Bioquarter, 47 Little France Crescent, Edinburgh EH16 4TJ, United Kingdom.

This commentary will discuss the use of advanced non-invasive imaging methodology for the pulmonary vascular system with special attention to a rubric for the imaging and clinical team to use for any particular clinical situation.
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http://dx.doi.org/10.1259/bjr.20200759DOI Listing
August 2020

What Do We Really Know About Pulmonary Thrombosis in COVID-19 Infection?

J Thorac Imaging 2020 Jun 29. Epub 2020 Jun 29.

Edinburgh Imaging, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK.

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http://dx.doi.org/10.1097/RTI.0000000000000545DOI Listing
June 2020

Pulmonary Vascular Disease Evaluation with Magnetic Resonance Angiography.

Radiol Clin North Am 2020 Jul 11;58(4):707-719. Epub 2020 May 11.

Department of Radiology, University of Wisconsin, 600 Highland Avenue, Madison, WI 53792, USA.

Pulmonary vascular assessment commonly relies on computed tomography angiography (CTA), but continued advances in magnetic resonance angiography have allowed pulmonary magnetic resonance angiography (pMRA) to become a reasonable alternative to CTA without exposing patients to ionizing radiation. pMRA allows the evaluation of pulmonary vascular anatomy, hemodynamic physiology, lung parenchymal perfusion, and (optionally) right and left ventricular function with a single examination. This article discusses pMRA techniques and artifacts; performance in commonly encountered pulmonary vascular diseases, specifically pulmonary embolism and pulmonary hypertension; and recent advances in both contrast-enhanced and noncontrast pMRA.
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http://dx.doi.org/10.1016/j.rcl.2020.02.006DOI Listing
July 2020

Ventilation defects on hyperpolarized helium-3 MRI in asthma are predictive of 2-year exacerbation frequency.

J Allergy Clin Immunol 2020 10 13;146(4):831-839.e6. Epub 2020 Mar 13.

Department of Medical Physics, University of Wisconsin-Madison, Madison, Wis; Department of Radiology, University of Wisconsin-Madison, Madison, Wis; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wis. Electronic address:

Background: There is an unmet need for an objective biomarker to predict asthma exacerbations.

Objective: Our aim was to assess the ventilation defect percent (VDP) on hyperpolarized helium-3 magnetic resonance imaging as a predictor of exacerbation frequency following imaging.

Methods: Subjects underwent hyperpolarized helium-3 and conventional clinical measurements, including pulmonary function tests, during a period of disease stability, and exacerbations were recorded prospectively over the following 2 years. We used a Poisson regression tree model to estimate an optimal VDP threshold for classifying subjects into high- versus low-exacerbation groups and then used statistical regression to compare this VDP threshold against conventional clinical measures as predictors of exacerbations.

Results: A total of 67 individuals with asthma (27 males and 40 females, 28 with mild-to-moderate asthma and 39 with severe asthma) had a median VDP of 3.75% (1.2% [first quartile]-7.9% [third quartile]). An optimal VDP threshold of 4.28% was selected on the basis of the maximum likelihood estimation of the regression tree model. Subjects with a VDP greater than 4.28% (n = 32) had a median of 1.5 exacerbations versus 0.0 for subjects with a VDP less than 4.28% (n = 35). In a stepwise multivariate regression model, a VDP greater than 4.28% was associated with an exacerbation incidence rate ratio of 2.5 (95% CI = 1.3-4.7) versus a VDP less than or equal to 4.28%. However, once individual medical history was included in the model, VDP was no longer significant. Nonetheless, VDP may provide an objective and complementary quantitative marker of individual exacerbation risk that is useful for monitoring individual change in disease status, selecting patients for therapy, and assessing treatment response.

Conclusion: VDP measured with magnetic resonance imaging shows promise as a biomarker of prospective asthma exacerbations.
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http://dx.doi.org/10.1016/j.jaci.2020.02.029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7487001PMC
October 2020

"Screening for lung cancer: Does MRI have a role?' [European Journal of Radiology 86 (2017) 353-360].

Eur J Radiol 2020 04 20;125:108896. Epub 2020 Feb 20.

Department of Diagnostic and Interventional Radiology, University Hospital of Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), Member of the German Lung ResearchCenter (DZL), Im Neuenheimer Feld 430, 69120 Heidelberg, Germany.

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http://dx.doi.org/10.1016/j.ejrad.2020.108896DOI Listing
April 2020

Radiologic, Pathologic, Clinical, and Physiologic Findings of Electronic Cigarette or Vaping Product Use-associated Lung Injury (EVALI): Evolving Knowledge and Remaining Questions.

Radiology 2020 Mar 28;294(3):491-505. Epub 2020 Jan 28.

From the Department of Radiology, University of California, San Diego, 200 W Arbor Dr, #8756, San Diego, CA 92013 (S.K.); Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (C.R.); Department of Laboratory Medicine and Pathology, Mayo Clinic, Scottsdale, Ariz (B.L., H.T.); Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, Calif (T.S.H.); Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pa (A.C., F.W.W.), Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wis (M.L.S., J.K.); and Department of Radiology, University of Vermont Medical Center, Burlington, Vt (J.S.K.).

Proposed as a safer alternative to smoking, the use of electronic cigarettes has not proven to be innocuous. With numerous deaths, there is an increasing degree of public interest in understanding the symptoms, imaging appearances, causes of, and treatment of electronic cigarette or vaping product use-associated lung injury (EVALI). Patients with EVALI typically have a nonspecific clinical presentation characterized by a combination of respiratory, gastrointestinal, and constitutional symptoms. EVALI is a diagnosis of exclusion; the patient must elicit a history of recent vaping within 90 days, other etiologies must be eliminated, and chest imaging findings must be abnormal. Chest CT findings in EVALI most commonly show a pattern of acute lung injury on the spectrum of organizing pneumonia and diffuse alveolar damage. The pathologic pattern found depends on when in the evolution of the disease process the biopsy sample is taken. Other less common forms of lung injury, including acute eosinophilic pneumonia and diffuse alveolar hemorrhage, have also been reported. Radiologists and pathologists help play an important role in the evaluation of patients suspected of having EVALI. Accurate and rapid identification may decrease morbidity and mortality by allowing for aggressive clinical management and glucocorticoid administration, which have been shown to decrease the severity of lung injury in some patients. In this review, the authors summarize the current state of the art for the imaging and pathologic findings of this disorder and outline a few of the major questions that remain to be answered.
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http://dx.doi.org/10.1148/radiol.2020192585DOI Listing
March 2020

Safety of repeated hyperpolarized helium 3 magnetic resonance imaging in pediatric asthma patients.

Pediatr Radiol 2020 05 24;50(5):646-655. Epub 2020 Jan 24.

Department of Radiology, University of Wisconsin-Madison, 111 Highland Ave., 2488 WIMR, Madison, WI, 53705, USA.

Background: Hyperpolarized helium 3 magnetic resonance imaging (He MRI) is useful for investigating pulmonary physiology of pediatric asthma, but a detailed assessment of the safety profile of this agent has not been performed in children.

Objective: To evaluate the safety of He MRI in children and adolescents with asthma.

Materials And Methods: This was a retrospective observational study. He MRI was performed in 66 pediatric patients (mean age 12.9 years, range 8-18 years, 38 male, 28 female) between 2007 and 2017. Fifty-five patients received a single repeated examination and five received two repeated examinations. We assessed a total of 127 He MRI exams. Heart rate, respiratory rate and pulse oximetry measured oxygen saturation (SpO) were recorded before, during (2 min and 5 min after gas inhalation) and 1 h after MRI. Blood pressure was obtained before and after MRI. Any subjective symptoms were also noted. Changes in vital signs were tested for significance during the exam and divided into three subject age groups (8-12 years, 13-15 years, 16-18 years) using linear mixed-effects models.

Results: There were no serious adverse events, but three minor adverse events (2.3%; headache, dizziness and mild hypoxia) were reported. We found statistically significant increases in heart rate and SpO after He MRI. The youngest age group (8-12 years) had an increased heart rate and a decreased respiratory rate at 2 min and 5 min after H inhalation, and an increased SpO post MRI.

Conclusion: The use of He MRI is safe in children and adolescents with asthma.
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http://dx.doi.org/10.1007/s00247-019-04604-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7153994PMC
May 2020

Assessing Radiology Research on Artificial Intelligence: A Brief Guide for Authors, Reviewers, and Readers-From the Editorial Board.

Radiology 2020 Mar 31;294(3):487-489. Epub 2019 Dec 31.

From the Department of Radiology, University of Wisconsin Madison School of Medicine and Public Health, 600 Highland Dr, Madison, WI 53792 (D.A.B., M.L.S.); Department of Radiology, New York University, New York, NY (L.M.); Department of Musculoskeletal Radiology (M.A.B.) and Institute for Technology Assessment (E.F.H.), Massachusetts General Hospital, Boston, Mass; Department of Medical Imaging, Hospital for Sick Children, University of Toronto, Toronto, Canada (B.B.E.W.); Department of Radiology, University of California-San Diego, San Diego, Calif (K.J.F.); Department of Cancer Imaging, Division of Imaging Sciences & Biomedical Engineering, Kings College London, London, England (V.J.G.); Department of Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco, Calif (C.P.H.); and Department of Radiology and Radiologic Science, The Johns Hopkins University School of Medicine, Baltimore, Md (C.R.W.).

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http://dx.doi.org/10.1148/radiol.2019192515DOI Listing
March 2020

Cost-effectiveness of lung MRI in lung cancer screening.

Eur Radiol 2020 Mar 20;30(3):1738-1746. Epub 2019 Nov 20.

Department of Industrial Engineering and Management Sciences, Northwestern University, Chicago, IL, USA.

Objectives: Recent studies with lung MRI (MRI) have shown high sensitivity (Sn) and specificity (Sp) for lung nodule detection and characterization relative to low-dose CT (LDCT). Using this background data, we sought to compare the potential screening performance of MRI vs. LDCT using a Markov model of lung cancer screening.

Methods: We created a Markov cohort model of lung cancer screening which incorporated lung cancer incidence, progression, and mortality based on gender, age, and smoking burden. Sensitivity (Sn) and Sp for LDCT were taken from the MISCAN Lung Microsimulation and Sn/Sp for MRI was estimated from a published substudy of the German Lung Cancer Screening and Intervention Trial. Screening, work-up, and treatment costs were estimated from published data. Screening with MRI and LDCT was simulated for a cohort of male and female smokers (2 packs per day; 36 pack/years of smoking history) starting at age 60. We calculated the screening performance and cost-effectiveness of MRI screening and performed a sensitivity analysis on MRI Sn/Sp and cost.

Results: There was no difference in life expectancy between MRI and LDCT screening (males 13.28 vs. 13.29 life-years; females 14.22 vs. 14.22 life-years). MRI had a favorable cost-effectiveness ratio of $258,169 in men and $403,888 in women driven by fewer false-positive screens. On sensitivity analysis, MRI remained cost effective at screening costs < $396 dollars and Sp > 81%.

Conclusions: In this Markov model of lung cancer screening, MRI has a near-equivalent life expectancy benefit and has superior cost-effectiveness relative to LDCT.

Key Points: • In this Markov model of lung cancer screening, there is no difference in mortality between yearly screening with MRI and low-dose CT. • Compared to low-dose CT, screening with MRI led to a reduction in false-positive studies from 26 to 2.8% in men and 26 to 2.6% in women. • Due to similar life-expectancy and reduced false-positive rate, we found a favorable cost-effectiveness ratio of $258,169 in men and $403,888 in women of MRI relative to low-dose CT.
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http://dx.doi.org/10.1007/s00330-019-06453-9DOI Listing
March 2020

Multicenter Safety and Practice for Off-Label Diagnostic Use of Ferumoxytol in MRI.

Radiology 2019 12 22;293(3):554-564. Epub 2019 Oct 22.

From the Diagnostic Cardiovascular Imaging Research Laboratory, Department of Radiological Sciences, David Geffen School of Medicine at UCLA, 300 Medical Plaza, Suite B119, Los Angeles, CA 90095 (K.L.N., T.Y., P.H., J.P.F.); Division of Cardiology, David Geffen School of Medicine at UCLA and VA Greater Los Angeles Healthcare System, Los Angeles, Calif (K.L.N., N.K.); Department of Radiology (I.H.Z., M.R.B.), Center for Advanced Magnetic Resonance Development (I.H.Z., M.R.B.), and Division of Gastroenterology, Department of Medicine (M.R.B.), Duke University Medical Center, Durham, NC; Department of Diagnostic Radiology and Neurology, Oregon Health Sciences University, Portland, Ore (C.G.V.); British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, Scotland (S.I.S., D.E.N.); Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, Calif (R.S.); Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Ill (C.K.R., L.M.G.); Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Ill (C.K.R., L.M.G.); Institute of Cardiovascular and Medical Sciences, University of Glasgow, Scotland (S.S., A.R.); Division of Cardiology, Department of Pediatrics and Radiology, Children's Hospital of Philadelphia, Philadelphia, Pa (K.K.W., M.A.F.); Department of Radiology, University of Wisconsin, Madison, Wis (L.M.G., M.L.S.); Department of Radiology, University of California, San Francisco and VA San Francisco Healthcare System, San Francisco, Calif (D.S., M.D.H.); Department of Radiology, Weill Medical College of Cornell University, New York, NY (M.R.P.); Department of Radiology, NHS Greater Glasgow and Clyde, and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, Scotland (G.H.R.); and Department of Neurology and Neurosurgery, Oregon Health Sciences University and VA Portland Healthcare System, Portland, Ore (E.A.N.).

Background Ferumoxytol is approved for use in the treatment of iron deficiency anemia, but it can serve as an alternative to gadolinium-based contrast agents. On the basis of postmarketing surveillance data, the Food and Drug Administration issued a black box warning regarding the risks of rare but serious acute hypersensitivity reactions during fast high-dose injection (510 mg iron in 17 seconds) for therapeutic use. Whereas single-center safety data for diagnostic use have been positive, multicenter data are lacking. Purpose To report multicenter safety data for off-label diagnostic ferumoxytol use. Materials and Methods The multicenter ferumoxytol MRI registry was established as an open-label nonrandomized surveillance databank without industry involvement. Each center monitored all ferumoxytol administrations, classified adverse events (AEs) using the National Cancer Institute Common Terminology Criteria for Adverse Events (grade 1-5), and assessed the relationship of AEs to ferumoxytol administration. AEs related to or possibly related to ferumoxytol injection were considered adverse reactions. The core laboratory adjudicated the AEs and classified them with the American College of Radiology (ACR) classification. Analysis of variance was used to compare vital signs. Results Between January 2003 and October 2018, 3215 patients (median age, 58 years; range, 1 day to 96 years; 1897 male patients) received 4240 ferumoxytol injections for MRI. Ferumoxytol dose ranged from 1 to 11 mg per kilogram of body weight (≤510 mg iron; rate ≤45 mg iron/sec). There were no systematic changes in vital signs after ferumoxytol administration ( > .05). No severe, life-threatening, or fatal AEs occurred. Eighty-three (1.9%) of 4240 AEs were related or possibly related to ferumoxytol infusions (75 mild [1.8%], eight moderate [0.2%]). Thirty-one AEs were classified as allergiclike reactions using ACR criteria but were consistent with minor infusion reactions observed with parenteral iron. Conclusion Diagnostic ferumoxytol use was well tolerated, associated with no serious adverse events, and implicated in few adverse reactions. Registry results indicate a positive safety profile for ferumoxytol use in MRI. © RSNA, 2019
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http://dx.doi.org/10.1148/radiol.2019190477DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6884068PMC
December 2019

Visualization of the Small Airways:What It Is and Why It Matters.

Radiology 2019 12 15;293(3):674-675. Epub 2019 Oct 15.

From the Department of Radiology, Professor of Cardiothoracic Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Ave, Madison, WI 53792-3252 (M.L.S.); and Department of Medical Biophysics and Robarts Research Institute, Western University, London, Canada (G.P.).

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http://dx.doi.org/10.1148/radiol.2019192025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6884066PMC
December 2019

Estimated Ventricular Size, Asthma Severity, and Exacerbations: The Severe Asthma Research Program III Cohort.

Chest 2020 02 12;157(2):258-267. Epub 2019 Sep 12.

Applied Chest Imaging Laboratory, Brigham and Women's Hospital, Boston, MA.

Background: Relative enlargement of the pulmonary artery (PA) on chest CT imaging is associated with respiratory exacerbations in patients with COPD or cystic fibrosis. We sought to determine whether similar findings were present in patients with asthma and whether these findings were explained by differences in ventricular size.

Methods: We measured the PA and aorta diameters in 233 individuals from the Severe Asthma Research Program III cohort. We also estimated right, left, and total epicardial cardiac ventricular volume indices (eERVVI, eELVVI, and eETVVI, respectively). Associations between the cardiac and PA measures (PA-to-aorta [PA/A] ratio, eERVVI-to-eELVVI [eRV/eLV] ratio, eERVVI, eELVVI, eETVVI) and clinical measures of asthma severity were assessed by Pearson correlation, and associations with asthma severity and exacerbation rate were evaluated by multivariable linear and zero-inflated negative binomial regression.

Results: Asthma severity was associated with smaller ventricular volumes. For example, those with severe asthma had 36.1 mL/m smaller eETVVI than healthy control subjects (P = .003) and 14.1 mL/m smaller eETVVI than those with mild/moderate disease (P = .011). Smaller ventricular volumes were also associated with a higher rate of asthma exacerbations, both retrospectively and prospectively. For example, those with an eETVVI less than the median had a 57% higher rate of exacerbations during follow-up than those with eETVVI greater than the median (P = .020). Neither PA/A nor eRV/eLV was associated with asthma severity or exacerbations.

Conclusions: In patients with asthma, smaller cardiac ventricular size may be associated with more severe disease and a higher rate of asthma exacerbations.

Trial Registry: ClinicalTrials.gov; No.: NCT01761630; URL: www.clinicaltrials.gov.
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http://dx.doi.org/10.1016/j.chest.2019.08.2185DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7005378PMC
February 2020

MRI in cardio-oncology: A review of cardiac complications in oncologic care.

J Magn Reson Imaging 2019 11 26;50(5):1349-1366. Epub 2019 Aug 26.

Department of Radiology, University of Wisconsin Madison, Madison, Wisconsin, USA.

From detailed characterization of cardiac abnormalities to the assessment of cancer treatment-related cardiac dysfunction, cardiac MRI is playing a growing role in the evaluation of cardiac pathology in oncology patients. Current guidelines are now incorporating the use of MRI for the comprehensive multidisciplinary approach to cancer management, and innovative applications of MRI in research are expanding its potential to provide a powerful noninvasive tool in the arsenal against cancer. This review focuses on the application of cardiac MRI to diagnose and manage cardiovascular complications related to cancer and its treatment. Following an introduction to current cardiac MRI methods and principles, this review is divided into two sections: functional cardiovascular analysis and anatomical or tissue characterization related to cancer and cancer therapeutics. Level of Evidence: 5 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;50:1349-1366.
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http://dx.doi.org/10.1002/jmri.26895DOI Listing
November 2019

Structural and Functional Features on Quantitative Chest Computed Tomography in the Korean Asian versus the White American Healthy Non-Smokers.

Korean J Radiol 2019 07;20(7):1236-1245

School of Mechanical Engineering, Kyungpook National University, Daegu, Korea.

Objective: Considering the different prevalence rates of diseases such as asthma and chronic obstructive pulmonary disease in Asians relative to other races, Koreans may have unique airway structure and lung function. This study aimed to investigate unique features of airway structure and lung function based on quantitative computed tomography (QCT)-imaging metrics in the Korean Asian population (Koreans) as compared with the White American population (Whites).

Materials And Methods: QCT data of healthy non-smokers (223 Koreans vs. 70 Whites) were collected, including QCT structural variables of wall thickness (WT) and hydraulic diameter (D) and functional variables of air volume, total air volume change in the lung (ΔV), percent emphysema-like lung (Emph%), and percent functional small airway disease-like lung (fSAD%). Mann-Whitney U tests were performed to compare the two groups.

Results: As compared with Whites, Koreans had smaller volume at inspiration, ΔV between inspiration and expiration ( < 0.001), and Emph% at inspiration ( < 0.001). Especially, Korean females had a decrease of ΔV in the lower lobes ( < 0.001), associated with fSAD% at the lower lobes ( < 0.05). In addition, Koreans had smaller D and WT of the trachea (both, < 0.05), correlated with the forced expiratory volume in 1 second (R = 0.49, 0.39; all < 0.001) and forced vital capacity (R = 0.55, 0.45; all < 0.001).

Conclusion: Koreans had unique features of airway structure and lung function as compared with Whites, and the difference was clearer in female individuals. Discriminating structural and functional features between Koreans and Whites enables exploration of inter-racial differences of pulmonary disease in terms of severity, distribution, and phenotype.
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http://dx.doi.org/10.3348/kjr.2019.0083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6609438PMC
July 2019

Comparison of gadolinium-enhanced and ferumoxytol-enhanced conventional and UTE-MRA for the depiction of the pulmonary vasculature.

Magn Reson Med 2019 11 22;82(5):1660-1670. Epub 2019 Jun 22.

Department of Radiology, University of Wisconsin-School of Medicine and Public Health, Madison, Wisconsin.

Purpose: To evaluate the feasibility of ferumoxytol (FE)-enhanced UTE-MRA for depiction of the pulmonary vascular and nonvascular structures.

Methods: Twenty healthy volunteers underwent contrast-enhanced pulmonary MRA at 3 T during 2 visits, separated by at least 4 weeks. Visit 1: The MRA started with a conventional multiphase 3D T -weighted breath-held spoiled gradient-echo MRA before and after the injection of 0.1 mmol/kg gadobenate dimeglumine (GD). Subsequently, free-breathing GD-UTE-MRA was acquired as a series of 3 flip angles (FAs) (6°, 12°, 18°) to optimize T weighting. Visit 2: After the injection of 4 mg/kg FE, MRA was performed during the steady state, starting with a conventional 3D T -weighted breath-held spoiled gradient-echo MRA and followed by free-breathing FE-UTE-MRA, both at 4 different FAs (6°, 12°, 18°, 24°). The optimal FA for best T contrast was evaluated. Image quality at the optimal FA was compared between methods on a 4-point ordinal scale, using multiphase GD conventional pulmonary MRA (cMRA) as standard of reference.

Results: Flip angle in the range of 18°-24° resulted in best T contrast for FE cMRA and both UTE-MRA techniques (p > .05). At optimized FA, image quality of the vasculature was good/excellent with both FE-UTE-MRA and GD cMRA (98% versus 97%; p = .51). Both UTE techniques provided superior depiction of nonvascular structures compared with either GD-enhanced or FE-enhanced cMRA (p < .001). However, GD-UTE-MRA showed the lowest image quality of the angiogram due to low image contrast.

Conclusion: Free-breathing UTE-MRA using FE is feasible for simultaneous assessment of the pulmonary vasculature and nonvascular structures. Patient studies should investigate the clinical utility of free-breathing UTE-MRA for assessment of pulmonary emboli.
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http://dx.doi.org/10.1002/mrm.27853DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6660410PMC
November 2019

Deep convolutional neural networks with multiplane consensus labeling for lung function quantification using UTE proton MRI.

J Magn Reson Imaging 2019 10 4;50(4):1169-1181. Epub 2019 Apr 4.

Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA.

Background: Ultrashort echo time (UTE) proton MRI has gained popularity for assessing lung structure and function in pulmonary imaging; however, the development of rapid biomarker extraction and regional quantification has lagged behind due to labor-intensive lung segmentation.

Purpose: To evaluate a deep learning (DL) approach for automated lung segmentation to extract image-based biomarkers from functional lung imaging using 3D radial UTE oxygen-enhanced (OE) MRI.

Study Type: Retrospective study aimed to evaluate a technical development.

Population: Forty-five human subjects, including 16 healthy volunteers, 5 asthma, and 24 patients with cystic fibrosis.

Field Strength/sequence: 1.5T MRI, 3D radial UTE (TE = 0.08 msec) sequence.

Assessment: Two 3D radial UTE volumes were acquired sequentially under normoxic (21% O ) and hyperoxic (100% O ) conditions. Automated segmentation of the lungs using 2D convolutional encoder-decoder based DL method, and the subsequent functional quantification via adaptive K-means were compared with the results obtained from the reference method, supervised region growing.

Statistical Tests: Relative to the reference method, the performance of DL on volumetric quantification was assessed using Dice coefficient with 95% confidence interval (CI) for accuracy, two-sided Wilcoxon signed-rank test for computation time, and Bland-Altman analysis on the functional measure derived from the OE images.

Results: The DL method produced strong agreement with supervised region growing for the right (Dice: 0.97; 95% CI = [0.96, 0.97]; P < 0.001) and left lungs (Dice: 0.96; 95% CI = [0.96, 0.97]; P < 0.001). The DL method averaged 46 seconds to generate the automatic segmentations in contrast to 1.93 hours using the reference method (P < 0.001). Bland-Altman analysis showed nonsignificant intermethod differences of volumetric (P ≥ 0.12) and functional measurements (P ≥ 0.34) in the left and right lungs.

Data Conclusion: DL provides rapid, automated, and robust lung segmentation for quantification of regional lung function using UTE proton MRI.

Level Of Evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1169-1181.
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http://dx.doi.org/10.1002/jmri.26734DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7039686PMC
October 2019

Differences in Particle Deposition Between Members of Imaging-Based Asthma Clusters.

J Aerosol Med Pulm Drug Deliv 2019 08 19;32(4):213-223. Epub 2019 Mar 19.

1Department of Mechanical Engineering, The University of Iowa, Iowa City, Iowa.

Four computed tomography (CT) imaging-based clusters have been identified in a study of the Severe Asthma Research Program (SARP) cohort and have been significantly correlated with clinical and demographic metrics ( 2017; 140:690-700.e8). We used a computational fluid dynamics (CFD) model to investigate air flow and aerosol deposition within imaging archetypes representative of the four clusters. CFD simulations for air flow and 1-8 μm particle transport were performed using CT-based airway models from two healthy subjects and eight asthma subjects. The subject selection criterion was based on the discriminant imaging-based flow-related variables of (Total) (average local volume expansion in the total lung) and *(sLLL) (normalized airway hydraulic diameter in the left lower lobe), where reduced (Total) and *(sLLL) indicate reduced regional ventilation and airway constriction, respectively. The analysis focused on the comparisons between all clusters with respect to healthy subjects, between cluster 2 and cluster 4 (nonsevere and severe asthma clusters with airway constriction) and between cluster 3 and cluster 4 (two severe asthma clusters characterized by normal and constricted airways, respectively). Nonsevere asthma cluster 2 and severe asthma cluster 4 subjects characterized by airway constriction had an increase in the deposition fraction (DF) in the left lower lobe. Constricted flows impinged on distal bifurcations resulting in large depositions. Although both cluster 3 (without constriction) and cluster 4 (with constriction) were severe asthma, they exhibited different particle deposition patterns with increasing particle size. The statistical analysis showed that *(sLLL) plays a more important role in particle deposition than (Total), and regional flow fraction is correlated with DF among lobes for smaller particles. We demonstrated particle deposition characteristics associated with cluster-specific imaging-based metrics such as airway constriction, which could pertain to the design of future drug delivery improvements.
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http://dx.doi.org/10.1089/jamp.2018.1487DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6685197PMC
August 2019