Sean B Fain

University of Wisconsin–Madison, Madison, Wisconsin, United States

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Publications (144)477.62 Total impact

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    ABSTRACT: This review focuses on the state-of-the-art of the three major classes of gas contrast agents used in magnetic resonance imaging (MRI)-hyperpolarized (HP) gas, molecular oxygen, and fluorinated gas-and their application to clinical pulmonary research. During the past several years there has been accelerated development of pulmonary MRI. This has been driven in part by concerns regarding ionizing radiation using multidetector computed tomography (CT). However, MRI also offers capabilities for fast multispectral and functional imaging using gas agents that are not technically feasible with CT. Recent improvements in gradient performance and radial acquisition methods using ultrashort echo time (UTE) have contributed to advances in these functional pulmonary MRI techniques. The relative strengths and weaknesses of the main functional imaging methods and gas agents are compared and applications to measures of ventilation, diffusion, and gas exchange are presented. Functional lung MRI methods using these gas agents are improving our understanding of a wide range of chronic lung diseases, including chronic obstructive pulmonary disease, asthma, and cystic fibrosis in both adults and children. J. Magn. Reson. Imaging 2015. © 2015 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 07/2015; DOI:10.1002/jmri.25002 · 2.79 Impact Factor
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    ABSTRACT: Bronchopulmonary dysplasia (BPD) is a prevalent yet poorly characterized pulmonary complication of premature birth; the current definition is based solely on oxygen dependence at 36 weeks postmenstrual age without objective measurements of structural abnormalities across disease severity. We hypothesize that magnetic resonance imaging (MRI) can spatially resolve and quantify the structural abnormalities of the neonatal lung parenchyma associated with premature birth. Using a unique, small-footprint, 1.5 T MRI scanner within our neonatal intensive care unit (NICU), diagnostic-quality MR images using commercially-available sequences (both gradient-echo and spin-echo) were acquired during quiet breathing in 6 BPD patients, 6 premature patients without diagnosed BPD, and 6 full-term NICU patients (gestational ages 23-39 weeks) at near term-equivalent age, without sedation or intravenous contrast. Images were scored by a radiologist using a modified Ochiai-score, and volumes of high- and low-signal intensity lung parenchyma were quantified by segmentation and threshold analysis. Signal increases, putatively combinations of fibrosis, edema, and atelectasis, were present in all premature infants. Infants with diagnosed BPD had significantly greater volume of high-signal lung (mean±SD, 26.1±13.8%) compared to full-term infants (7.3±8.2%, p=0.020) and premature infants without BPD (8.2±6.4%, p=0.026). Signal decreases, presumably alveolar simplification, only appeared in the most severe BPD cases, though cystic appearance did increase with severity. Pulmonary MRI reveals quantifiable, significant differences between BPD patients, premature patients without BPD, and full-term controls; these methods could be implemented to individually phenotype disease, which may impact clinical care and predict future outcomes.
    American Journal of Respiratory and Critical Care Medicine 07/2015; DOI:10.1164/rccm.201503-0552OC · 11.99 Impact Factor
  • H Chen-Mayer · S Fain · P Judy
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    ABSTRACT: Low dose CT for lung densitometry has shown utility in evaluating severity and progression of pulmonary emphysema in patients with chronic obstructive pulmonary disease (COPD). Effort is underway at QIBA to standardize measurement protocols based on published longitudinal studies on non-diseased subjects. The purpose of this report is to assess an important component of the densitometry CT data interpretation: the volume adjustment necessary to reduce the effect of respiration on density. The 15 percentile density scores (Perc 15), defined as a threshold HU containing 15% lowest density in the attenuation histogram of the whole lung, were compiled for 30 subjects obtained from the National Lung Cancer Trial database with baseline and repeat scans one year apart. A model assuming an adapted sponge model, where the relationship between volume (V) and density (rho) is given by m=rhoV^s (Staring et al, Med. Phys. 41, 021905 (2014)). s can be obtained for each subject, and for the entire sample, which allowed adjustment of the Perc15 value at the repeat scan both at the sample level and for each subject. The average bias (change between scan 2 and 1) and standard deviation (SD) of the bias for a) unadjusted, b) sample-level adjusted, and c) subject-level adjusted Perc 15 (HU) values are 2.0 (13.7), 1.5 (3.6), and 2.4 (9.8), respectively, suggesting that the method of volume adjustment affects the assessment of the accuracy and precision of the measurement. Method b) improves both more than c). The distribution of the value s indicates that less than 1/5 of the subjects followed the sponge-like behavior (unity s). Volume adjustment has a major impact on the assessment of accuracy and precision of quantitative lung density CT, and therefore the interpretation directly influence the decision making in a clinical setting. Sean Fain receives grant funding from GE Healthcare.
    Medical Physics 06/2015; 42(6):3634. DOI:10.1118/1.4925772 · 3.01 Impact Factor
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    American Thoracic Society 2015, Denver; 05/2015
  • David J Niles · Jeremy W Gordon · Sean B Fain
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    ABSTRACT: Blood oxygen level-dependent (BOLD) MRI is increasingly being used to assess renal tissue oxygenation during disease based on the transverse relaxation rate (R2 *). In preclinical small animal models, the requisite use of anesthesia during imaging may lead to functional changes which influence R2 * and confound results. The purpose of this study was to evaluate the effects of four common anesthetic compounds on renal R2 * in healthy mice. Five female ICR mice were imaged with BOLD MRI approximately 25 min after induction with isoflurane (Iso; 1% or 1.5%, delivered in 100% O2 ), ketamine/xylazine (KX), sodium pentobarbital (PB) or 2,2,2-tribromoethanol (TBE). A significant effect of anesthetic agent on R2 * was observed in all tissue layers of the kidney, including the cortex, outer stripe of the outer medulla (OSOM), inner stripe of the outer medulla (ISOM) and inner medulla (IM). Pairwise significant differences in R2 * between specific agents were found in the cortex, OSOM and ISOM, with the largest difference observed in the ISOM between 1.5% Iso (26.6 ± 1.7 s(-1) ) and KX (66.0 ± 7.1 s(-1) ). The difference between 1% Iso and KX in the ISOM was not abolished when KX was administered with supplemental 100% O2 or when 1% Iso was delivered in 21% O2 , indicating that the fraction of inspired oxygen did not account for the observed differences. Our results indicate that the choice of anesthesia has a large influence on the observed R2 * in mouse kidney, and anesthetic effects must be considered in the design and interpretation of renal BOLD MRI studies. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    NMR in Biomedicine 05/2015; 28(7). DOI:10.1002/nbm.3314 · 3.56 Impact Factor
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    ABSTRACT: To develop the use of bipolar gradients to suppress partial-volume and flow-related artifacts from macrovascular, hyperpolarized spins. Digital simulations were performed over a range of spatial resolutions and gradient strengths to determine the optimal bipolar gradient strength and duration to suppress flowing spins while minimizing signal loss from static tissue. In vivo experiments were performed to determine the efficacy of this technique to suppress vascular signal in the study of hyperpolarized [1-(13) C]pyruvate renal metabolism. Digital simulations showed that in the absence of bipolar gradients, partial-volume artifacts from the vasculature were still present, causing underestimation of the apparent reaction rate of pyruvate to lactate (kP ). The addition of a bipolar gradient with b = 32 s/mm(2) sufficiently suppressed the vascular signal without a substantial decrease in signal from static tissue. In vivo results corroborate digital simulations, with similar peak lactate signal to noise ratio (SNR) but substantially different kP in the presence of bipolar gradients. The proposed approach suppresses signal from flowing spins while minimizing signal loss from static tissue, removing contaminating signal from the vasculature and increasing kinetic modeling accuracy without substantially sacrificing SNR or temporal resolution. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 05/2015; DOI:10.1002/mrm.25584 · 3.40 Impact Factor
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    ABSTRACT: We reduced the computed tomography (CT)-reconstructed field of view (FOV), increasing pixel density across airway structures and reducing partial volume effects, to determine whether this would improve accuracy of airway wall thickness quantification. We performed CT imaging on a lung phantom and 29 participants. Images were reconstructed at 30-, 15-, and 10-cm FOV using a medium-smooth kernel. Cross-sectional airway dimensions were compared at each FOV with repeated-measures analysis of variance. Phantom measurements were more accurate when FOV decreased from 30 to 15 cm (P < 0.05). Decreasing FOV further to 10 cm did not significantly improve accuracy. Human airway measurements similarly decreased by decreasing FOV (P < 0.001). Percent changes in all measurements when reducing FOV from 30 to 15 cm were less than 3%. Airway measurements at 30-cm FOV are near the limits of CT resolution using a medium-smooth kernel. Reducing reconstructed FOV would minimally increase sensitivity to detect differences in airway dimensions.
    Journal of computer assisted tomography 05/2015; Publish Ahead of Print. DOI:10.1097/RCT.0000000000000238 · 1.60 Impact Factor
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    ABSTRACT: Relationships between structural and functional variables in asthmatic lungs at local and global (or lobar) levels remain to be discovered. This study aims to investigate local alterations of structural variables (bifurcation angle θ, circularity Cr, airway wall thickness WT and hydraulic diameter Dh) in asthmatics, and their correlations with other imaging and pulmonary function tests (PFT) based global and lobar metrics including lung shape, air-trapping, regional volume change and more. 61 healthy subjects, 67 non-severe and 67 severe asthmatics were studied. The structural variables were derived from CT images at total lung capacity (TLC). Air-trapping was measured at functional residual capacity (FRC), and regional volume change (derived from image registration) was measured between FRC and TLC. The tracheal diameter and wall thickness predicted by 61 healthy subjects were used to normalize the Dh and WT. New normalization schemes allowed for the dissociation of luminal narrowing and wall thickening effects. In severe asthmatics, the alteration of θ was found to be correlated with a global lung shape at TLC, and Cr was significantly decreased in the right main bronchus. While normalized WT increased especially in the upper lobes of severe asthmatics, normalized Dh decreased in the lower lobes. Among local structural variables, normalized Dh was the most representative variable, because it was significantly correlated with alterations of functional variables including PFT's data. In conclusion, understanding multiscale phenomena may help to provide guidance in the search for potential imaging-based phenotypes for the development and outcomes assessment of therapeutic intervention.
    Journal of Applied Physiology 03/2015; · 3.43 Impact Factor
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    ABSTRACT: Relationships between structural and functional variables in asthmatic lungs at local and global (or lobar) levels remain to be discovered. This study aims to investigate local alterations of structural variables (bifurcation angle θ, circularity Cr, airway wall thickness WT and hydraulic diameter Dh) in asthmatics, and their correlations with other imaging and pulmonary function tests (PFT) based global and lobar metrics including lung shape, air-trapping, regional volume change and more. 61 healthy subjects, 67 non-severe and 67 severe asthmatics were studied. The structural variables were derived from CT images at total lung capacity (TLC). Air-trapping was measured at functional residual capacity (FRC), and regional volume change (derived from image registration) was measured between FRC and TLC. The tracheal diameter and wall thickness predicted by 61 healthy subjects were used to normalize the Dh and WT. New normalization schemes allowed for the dissociation of luminal narrowing and wall thickening effects. In severe asthmatics, the alteration of θ was found to be correlated with a global lung shape at TLC, and Cr was significantly decreased in the right main bronchus. While normalized WT increased especially in the upper lobes of severe asthmatics, normalized Dh decreased in the lower lobes. Among local structural variables, normalized Dh was the most representative variable, because it was significantly correlated with alterations of functional variables including PFT's data. In conclusion, understanding multiscale phenomena may help to provide guidance in the search for potential imaging-based phenotypes for the development and outcomes assessment of therapeutic intervention. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 03/2015; 118:jap.01094.2014. DOI:10.1152/japplphysiol.01094.2014 · 3.43 Impact Factor
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    ABSTRACT: Real-time imaging of (13) C metabolism in vivo has been enabled by recent advances in hyperpolarization. As a result of the inherently low natural abundance of endogenous (13) C nuclei, hyperpolarized (13) C images lack structural information that could be used to aid in motion detection and anatomical registration. Motion before or during the (13) C acquisition can therefore result in artifacts and misregistration that may obscure measures of metabolism. In this work, we demonstrate a method to simultaneously image both (1) H and (13) C nuclei using a dual-nucleus spectral-spatial radiofrequency excitation and a fully coincident readout for rapid multinuclear spectroscopic imaging. With the appropriate multinuclear hardware, and the means to simultaneously excite and receive on both channels, this technique is straightforward to implement requiring little to no increase in scan time. Phantom and in vivo experiments were performed with both Cartesian and spiral trajectories to validate and illustrate the utility of simultaneous acquisitions. Motion compensation of dynamic metabolic measurements acquired during free breathing was demonstrated using motion tracking derived from (1) H data. Simultaneous multinuclear imaging provides structural (1) H and metabolic (13) C images that are correlated both spatially and temporally, and are therefore amenable to joint (1) H and (13) C analysis and correction of structure-function images. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    NMR in Biomedicine 03/2015; 28(5). DOI:10.1002/nbm.3279 · 3.56 Impact Factor
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    ABSTRACT: Sex influences the risk of wheezing illnesses and the prevalence of asthma throughout childhood. To better understand the mechanisms of these effects, we analyzed longitudinal relationships between sex, lung physiology, and asthma in the Childhood Origins of ASThma birth cohort study. Childhood Origins of ASThma birth cohort study children were followed prospectively from birth and assessed annually. Results of spirometry, fractional exhaled nitric oxide (Feno), mannitol provocation testing, and (3)He gas magnetic resonance imaging were assessed by sex using multivariate models including age, asthma diagnosis, and wheezing histories. Girls had higher prebronchodilator forced expiratory volume in 0.5 seconds/forced vital capacity values than did boys (mean difference, 0.017; 95% CI, 0.000-0.034; P = .05) of equivalent age. Postbronchodilator findings were more pronounced, with boys demonstrating reduced forced expiratory volume in 0.5 seconds/forced vital capacity values than did girls of equivalent age (mean difference, 0.032; 95% CI, 0.014-0.049; P = .0005). Conversely, girls were noted to have higher ventilation defects on (3)He magnetic resonance imaging than did boys (P = .01). No differences were noted in the rate of positive responses to mannitol provocation or Feno measurements. Lower airflow values are present by spirometry for prepubertal boys than for age-matched girls; however, greater (3)He ventilation defects were noted in girls. This could represent a greater degree of subclinical air trapping in prepubertal girls because residual volumes are not detected on standard spirometric readings. No differences were noted between the 2 sexes with airway hyperresponsiveness (mannitol provocation testing) or inflammation (Feno). Prospective peripubertal follow-up will determine whether these differences persist or change with the de novo expression and remission of asthma based on sex and age. Copyright © 2015 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.
    Journal of Allergy and Clinical Immunology 02/2015; DOI:10.1016/j.jaci.2014.12.1927 · 11.25 Impact Factor
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    ABSTRACT: To develop and demonstrate a breathheld 3D radial ultrashort echo time (UTE) acquisition to visualize co-registered lung perfusion and vascular structure. Nine healthy dogs were scanned twice at 3 Tesla (T). Contrast-enhanced pulmonary perfusion scans were acquired with a temporally interleaved three-dimensional (3D) radial UTE (TE = 0.08 ms) sequence in a breathhold (1 s time frames over a 33 s breathhold). The 3D breathheld volume was reconstructed into time-resolved perfusion datasets, and a composite vascular structure dataset. For structural comparison, a 5 min respiratory-gated 3D radial UTE scan was acquired. Data were analyzed by quantitative metrics and radiologist scoring. Appropriate time-course of contrast was seen in all subjects. Right ventricle to aorta transit times were 7.4 ± 2.0 s. Relative lung enhancement was a factor of 8.4 ± 1.5. Radiologist scoring showed similarly excellent visualization of the pulmonary arteries to the subsegmental level in breathheld (94% of cases) and respiratory-gated (100% of cases) acquisitions (P = 0.33) despite the aggressive under sampling in the breathheld scan. Similarly, differentiation of lung tissue and airways was achieved by both acquisition methods. A time-resolved 3D radial UTE sequence for simultaneous imaging of pulmonary perfusion and co-registered vascular structure is feasible.J. Magn. Reson. Imaging 2013. © 2013 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 01/2015; 41(1). DOI:10.1002/jmri.24520 · 2.79 Impact Factor
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    ABSTRACT: The objectives of this study were to compare pulmonary blood flow (PBF) measurements acquired with 3 previously published models (low-dose "single bolus," "dual bolus" and a "nonlinear correction" algorithm) for addressing the nonlinear relationship between contrast agent concentration and magnetic resonance signal in the arterial input function (AIF) and to compare both lung signal and PBF measurements obtained using gadopentetate dimeglumine (Gd-DTPA, Magnevist) with those obtained using the high-relaxivity agent gadobenate dimeglumine (Gd-BOPTA, Multihance). Ten of 12 healthy humans were successfully scanned on 2 consecutive days at 1.5 T. Contrast-enhanced pulmonary perfusion scans were acquired with a 3-dimensional spoiled gradient echo pulse sequence and interleaved variable density k-space sampling with a 1-second frame rate and 4 × 4 × 4-mm resolution. Each day, 2 perfusion scans were acquired with either Gd-DTPA or Gd-BOPTA; the order of the administered contrast agent was randomized. Region of interest analysis was used to determine PBF on the basis of the indicator dilution theory. Linear mixed-effects modeling was used to compare the AIF models and contrast agents. With Gd-DTPA, no significant differences were observed between the mean PBF calculated for the single bolus (323 ± 110 mL/100mL/min), dual bolus (315 ± 177 mL/100mL/min), and nonlinear correction (298 ± 100 mL/100mL/min) approach. With Gd-BOPTA, the mean PBF using the dual bolus approach (245 ± 103 mL/100mL/min) was lower than with the single bolus (345 ± 130 mL/100mL/min P < 0.01) and nonlinear correction (321 ± 115 mL/100mL/min; P = 0.02). Peak lung enhancement was significantly higher in all regions with Gd-BOPTA than with Gd-DTPA (P < 0.01). The dual bolus approach with Gd-BOPTA resulted in a significantly lower PBF than did the other combinations of contrast agent and AIF model. No other statistically significant differences were found. Given the much higher signal in the lung parenchyma using Gd-BOPTA, the use of Gd-BOPTA with either single bolus or the nonlinear correction method appears most promising for voxelwise perfusion quantification using 3-dimensional dynamic contrast-enhanced pulmonary perfusion magnetic resonance imaging.
    Investigative Radiology 12/2014; 50(3). DOI:10.1097/RLI.0000000000000122 · 4.45 Impact Factor
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    ABSTRACT: The purpose of this work was to use 3D radial ultrashort echo time (UTE) MRI to perform whole-lung oxygen-enhanced (OE) imaging in humans. Eight healthy human subjects underwent two 3D radial UTE MRI acquisitions (TE = 0.08 ms): one while breathing 21% O2 and the other while breathing 100% O2 . Scans were each performed over 5 min of free breathing, using prospective respiratory gating. For comparison purposes, conventional echo time (TE = 2.1 ms) images were acquired simultaneously during each acquisition using a radial " outward-inward" k-space trajectory. 3D percent OE maps were generated from these images. 3D OE maps showing lung signal enhancement were generated successfully in seven subjects (technical failure in one subject). Mean percent signal enhancement was 6.6% ± 1.8%, near the value predicted by theory of 6.3%. No significant enhancement was seen using the conventional echo time data, confirming the importance of UTE for this acquisition strategy. 3D radial UTE MRI shows promise as a method for OE MRI that enables whole-lung coverage and isotropic spatial resolution, in comparison to existing 2D OE methods, which rely on a less time-efficient inversion recovery pulse sequence. These qualities may help OE MRI become a viable low-cost method for 3D imaging of lung function in human subjects. Copyright © 2014 John Wiley & Sons, Ltd.
    NMR in Biomedicine 12/2014; 27(12). DOI:10.1002/nbm.3158 · 3.56 Impact Factor
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    ABSTRACT: To determine the impact of constrained reconstruction techniques on quantitative CT (qCT) of the lung parenchyma and airways for low x-ray radiation dose.
    Medical Physics 11/2014; 41(11):111911. DOI:10.1118/1.4898098 · 3.01 Impact Factor
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    ABSTRACT: S-nitrosoglutathione is an endogenous airway smooth muscle relaxant. Increased airway S-nitrosoglutathione breakdown occurs in some asthma patients. We asked whether patients with increased airway catabolism of this molecule had clinical features that distinguished them from other asthma patients. We measured S-nitrosoglutathione reductase expression and activity in bronchoscopy samples taken from 66 subjects in the Severe Asthma Research Program. We also analysed phenotype and genotype data taken from the program as a whole. Airway S-nitrosoglutathione reductase activity was increased in asthma patients (p = 0.032). However, only a subpopulation was affected and this subpopulation was not defined by a "severe asthma" diagnosis. Subjects with increased activity were younger, had higher IgE and an earlier onset of symptoms. Consistent with a link between S-nitrosoglutathione biochemistry and atopy: 1) interleukin 13 increased S-nitrosoglutathione reductase expression and 2) subjects with an S-nitrosoglutathione reductase single nucleotide polymorphism previously associated with asthma had higher IgE than those without this single nucleotide polymorphism. Expression was higher in airway epithelium than in smooth muscle and was increased in regions of the asthmatic lung with decreased airflow. An early-onset, allergic phenotype characterises the asthma population with increased S-nitrosoglutathione reductase activity.
    European Respiratory Journal 10/2014; 45(1). DOI:10.1183/09031936.00042414 · 7.13 Impact Factor
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    ABSTRACT: Rationale and Objectives Previous cross-sectional studies have demonstrated that airway wall thickness and air trapping are greater in subjects with severe asthma than in those with mild-to-moderate asthma. However, a better understanding of how airway remodeling and lung density change over time is needed. This study aimed to evaluate predictors of airway wall remodeling and change in lung function and lung density over time in severe asthma. Materials and methods Phenotypic characterization and quantitative multidetector-row computed tomography (MDCT) of the chest were performed at baseline and ∼2.6 years later in 38 participants with asthma (severe n = 24 and mild-to-moderate n = 14) and nine normal controls from the Severe Asthma Research Program. Results Subjects with severe asthma had a significant decline in postbronchodilator forced expiratory volume in 1 second percent (FEV1%) predicted over time (P < .001). Airway wall thickness measured by MDCT was increased at multiple airway generations in severe asthma compared to mild-to-moderate asthma (wall area percent [WA%]: P < .05) and normals (P < .05) at baseline and year 2. Over time, there was an increase in WA% and wall thickness percent (WT%) in all subjects (P = .030 and .009, respectively) with no change in emphysema-like lung or air trapping. Baseline prebronchodilator FEV1% inversely correlated with WA% and WT% (both P < .05). In a multivariable regression model, baseline WA%, race, and health care utilization were predictors of subsequent airway remodeling. Conclusions Severe asthma subjects have a greater decline in lung function over time than normal subjects or those with mild-to-moderate asthma. MDCT provides a noninvasive measure of airway wall thickness that may predict subsequent airway remodeling.
    Academic Radiology 08/2014; 21(8):986–993. DOI:10.1016/j.acra.2014.05.001 · 2.08 Impact Factor
  • E Adamson · J Gordon · K Johnson · S Fain
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    ABSTRACT: Purpose: Previous work [1] modeling the metabolic flux between hyperpolarized [1-13C]pyruvate and [1-13C]lactate in magnetic resonance spectroscopic imaging (MRSI) experiments failed to account for vascular signal artifacts. Here, we investigate a method to minimize the vascular signal and its impact on the fidelity of metabolic modeling.
    Medical Physics 06/2014; 41(6):379-379. DOI:10.1118/1.4888991 · 3.01 Impact Factor
  • B Bednarz · K Ludwig · S Fain
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    ABSTRACT: Purpose: Despite the widespread use of fluorinated hydrocarbons for inhalational anesthesia very little is known about the role of these anesthetics in postoperative cognitive impairment. There is a compelling need for safe and effective quantitative and qualitative imaging techniques to monitor the spatial distribution of inhalational anesthetics in vivo to appropriately assess this role. Herein we present a pilot study on the use of 1 9F MRI to image fluorinated anesthetics in vivo.
    Medical Physics 06/2014; 41(6):378-378. DOI:10.1118/1.4888989 · 3.01 Impact Factor
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    ABSTRACT: Purpose: Adaptive radiotherapy requires a knowledge of the changing local tumor oxygen concentrations for times on the order of the treatment time, a time scale far shorter than cell death and proliferation. This knowledge will be needed to guide hypofractionated radiotherapy.
    Medical Physics 06/2014; 41(6):435-435. DOI:10.1118/1.4889198 · 3.01 Impact Factor

Publication Stats

2k Citations
477.62 Total Impact Points

Institutions

  • 2001–2015
    • University of Wisconsin–Madison
      • • Department of Medical Physics
      • • Department of Radiology
      Madison, Wisconsin, United States
  • 2012
    • University of Illinois at Chicago
      Chicago, Illinois, United States
  • 2006–2008
    • University of Wisconsin - Stout
      Menominee, Wisconsin, United States
  • 2005
    • University of Leicester
      Leiscester, England, United Kingdom
  • 1999–2001
    • Mayo Clinic - Rochester
      • Department of Radiology
      Rochester, Minnesota, United States