Sean Fain

Sean Fain
University of Iowa | UI · Department of Radiology

Professor

About

249
Publications
16,489
Reads
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7,020
Citations
Citations since 2016
83 Research Items
4199 Citations
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20162017201820192020202120220200400600800
20162017201820192020202120220200400600800
20162017201820192020202120220200400600800

Publications

Publications (249)
Article
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.
Article
Rationale: Dynamic collapse of the tracheal lumen (tracheomalacia) occurs frequently in premature neonates, particularly those with common comorbidities such as bronchopulmonary dysplasia. The tracheal collapse increases the effort necessary to breathe (work of breathing, WOB). However, quantifying the increased WOB related to tracheomalacia has p...
Article
Full-text available
Background Hyperpolarized helium 3 magnetic resonance imaging (³He 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 ³He MRI in children and adolescents with asthma. Materials and methods T...
Article
Purpose: Multiple commercial, open-source, and academic software tools exist for objective quantification of lung density in computed tomography (CT) images. The purpose of this study was evaluate the inter-software reproducibility of CT lung density measurements. Methods: CT images from 50 participants from the COPDGeneTM cohort study were rand...
Article
Purpose The MR properties (chemical shifts and decay rates) of dissolved‐phase hyperpolarized (HP) ¹²⁹Xe are confounded by the large magnetic field inhomogeneity present in the lung. This work improves measurements of these properties using a model‐based image reconstruction to characterize the decay rates of dissolved‐phase HP ¹²⁹Xe in healthy sub...
Article
Purpose: The goal of this study was to develop a methodology to investigate the relationship between contractile function and hyperpolarized (HP) [1-13C]pyruvate metabolism in a small animal model. To achieve sufficient signal from HP 13C compounds, HP 13C MRS/MRSI has required relatively large infusion volumes relative to the total blood volume i...
Article
Purpose Novel demonstration of and tissue density estimation in infant lungs using 3D ultrashort echo time MRI. Differences between adult and neonates with no clinical indication of lung pathology is explored, as well as relationships between parameter estimates and gravitationally dependent position and lung inflation state. This provides a tool f...
Article
Purpose: A multiecho, field of view (FOV)-oversampled k-t spiral acquisition and direct iterative decomposition of water and fat with echo asymmetry and least-squares estimation reconstruction is demonstrated to improve the stability of hyperpolarized 13 C magnetic resonance spectroscopic imaging (MRSI) in the presence of signal ambiguities attrib...
Article
Full-text available
Objectives: This study aimed at developing technical recommendations for the acquisition, processing and analysis of renal ASL data in the human kidney at 1.5 T and 3 T field strengths that can promote standardization of renal perfusion measurements and facilitate the comparability of results across scanners and in multi-centre clinical studies....
Article
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Harmonization of acquisition and analysis protocols is an important step in the validation of BOLD MRI as a renal biomarker. This harmonization initiative provides technical recommendations based on a consensus report with the aim to move towards standardized protocols that facilitate clinical translation and comparison of data across sites. We use...
Article
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Purpose The potential of renal MRI biomarkers has been increasingly recognised, but clinical translation requires more standardisation. The PARENCHIMA consensus project aims to develop and apply a process for generating technical recommendations on renal MRI. Methods A task force was formed in July 2018 focused on five methods. A draft process for...
Article
Objectives: To assess the feasibility of ferumoxytol-enhanced MRI in pregnancy with a nonhuman primate model. Materials and methods: In this prospective study, eleven pregnant rhesus macaques at day 98 ± 5 of gestation were divided into three groups, untreated control (UC) (n = 3), saline control (SC) (n = 4) and interleukin 1 beta (IL-1β) treat...
Article
The magnitude and regional heterogeneity of airway obstructions in severe asthmatics is likely linked to insufficient drug delivery, as evidenced by the inability to mitigate exacerbations with inhaled aerosol medications. To understand the correlation between morphometric features, airflow distribution, and inhaled dosimetry, we perform dynamic co...
Article
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 mea...
Article
Background: 3D chemical shift-encoded (CSE)-MRI techniques enable assessment of ferumoxytol concentration but are unreliable in the presence of motion. Purpose: To evaluate a motion-robust 2D-sequential CSE-MRI for R2* and B0 mapping in ferumoxytol-enhanced MRI of the placenta. Study type: Prospective. Animal model: Pregnant rhesus macaques....
Article
Full-text available
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 (QC...
Article
Background Bronchopulmonary dysplasia (BPD) is a chronic lung disease of prematurity defined by requirement for respiratory support at 36 weeks postmenstrual age (PMA), but structural sequelae like lung hyperinflation are often not quantified. Quiet‐breathing, nonsedated magnetic resonance imaging (MRI) allows tomographic quantification of lung vol...
Article
Background MRI of hyperpolarized ¹²⁹Xenon (HP ¹²⁹Xe) is increasingly utilized for investigating pulmonary function. The solubility of HP ¹²⁹Xe in lung tissue, blood plasma (Barrier), and red blood cells (RBC), with unique chemical shifts, enables spectroscopic imaging of potential imaging biomarkers of gas exchange and microstructural pulmonary phy...
Article
Background: 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 (J Allergy Clin Immunol 2017; 140:690-700.e8). We used a computational fluid dynamics (CFD) model to investigate air flow an...
Article
Air-trapping due to airway closure has been associated with unstable asthma. In addition to airway closure that occurs at lower lung volumes during slow expiration, there may be further closure during a forced expiration, due to airway compression. The purpose of this study was to define a reference range from a non-asthma population, and to invest...
Article
Full-text available
Rationale and objectives: The purpose of this review is to acquaint the reader with recent advances in ultrashort echo time (UTE) magnetic resonance imaging (MRI) of the lung and its implications for pulmonary MRI when used in conjunction with functional MRI technique. Materials and methods: We provide an overview of recent technical advances of...
Article
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Purpose Fluorescence lifetime imaging microscopy (FLIM) of endogenous fluorescent metabolites permits the measurement of cellular metabolism in cell, tissue and animal models. In parallel, magnetic resonance spectroscopy (MRS) of dynamic nuclear (hyper)polarized (DNP) ¹³C‐pyruvate enables measurement of metabolism at larger in vivo scales. Presente...
Article
Full-text available
Purpose: To compare the performance of three-dimensional radial ultrashort echo time (UTE) oxygen-enhanced (OE) MRI with that of hyperpolarized helium 3 (3He) MRI with respect to quantitative ventilation measurements in patients with cystic fibrosis (CF). Materials and Methods: In this prospective study conducted from June 2013 to May 2015, 25 par...
Article
Purpose To investigate the correspondence between arterial spin labeling (ASL) flow‐sensitive alternating inversion recovery (FAIR) and ferumoxytol DCE MRI for the assessment of placental intervillous perfusion. Methods Ten pregnant macaques in late second trimester were imaged at 3 T using a 2D ASL FAIR, with and without outer‐volume saturation p...
Article
Background Neonatal dynamic tracheal collapse (tracheomalacia, TM) is a common and serious comorbidity in infants, particularly those with chronic lung disease of prematurity (bronchopulmonary dysplasia, BPD) or congenital airway or lung‐related conditions such as congenital diaphragmatic hernia (CDH), but the underlying pathology, impact on clinic...
Article
Rationale: Hyperpolarized 129Xe MRI enables quantitative evaluation of regional ventilation. To this end, multiple classifiers have been proposed to determine ventilation defect percentage (VDP) as well as other cluster populations. However, consensus has not yet been reached regarding which of these methods to deploy for multicenter clinical tria...
Article
Purpose A novel technique is presented for retrospective estimation and removal of gas‐phase hyperpolarized Xenon‐129 (HP ¹²⁹Xe) from images of HP ¹²⁹Xe dissolved in the barrier (comprised of parenchymal lung tissue and blood plasma) and red blood cell (RBC) phases. The primary aim is mitigating RF pulse performance limitations on measures of gas e...
Article
At the time of publication, our group had performed short tandem repeat (STR) testing on the SCC22B cell line and believed that had been correctly identified. As part of a recent comprehensive process to confirm the identity of cell lines in use in our lab, we repeated STR testing on all cell lines. These results were compared to the ExPASy Cellosa...
Article
Rationale: Bronchopulmonary dysplasia (BPD) is a serious neonatal pulmonary condition associated with premature birth, but the underlying parenchymal disease and trajectory are poorly characterized. The current NICHD/NHLBI definition of BPD severity is based on degree of prematurity and extent of oxygen requirement. However, no clear link exists b...
Conference Paper
Reducing the frequency of exacerbations is the primary goal of asthma disease management. Severe asthmatics (~15% of asthmatics) are challenging to treat, as this cohort of patients does not respond well to inhaled therapeutics. Computational fluid dynamics and particle transport (CFD-PT) simulations provide unique insight on contributing factors t...
Article
Rationale: Loss of the peripheral pulmonary vasculature, termed vascular pruning, is associated with disease severity in patients with chronic obstructive pulmonary disease. Objectives: To determine if pulmonary vascular pruning is associated with asthma severity and exacerbations. Methods: We measured the total pulmonary blood vessel volume (...
Article
Full-text available
Background: The link between mucus plugs and airflow obstruction has not been established in chronic severe asthma, and the role of eosinophils and their products in mucus plug formation is unknown. Methods: In clinical studies, we developed and applied a bronchopulmonary segment-based scoring system to quantify mucus plugs on multidetector comp...
Article
Background: Quantitative computed tomography (QCT) biomarkers of airway morphology hold potential for understanding and monitoring regional airway remodeling in asthma. Objective: We sought to determine if the change of airway lumen area between TLC and FRC lung volumes measured from CT imaging data was correlated with severe outcomes in asthma...
Article
Full-text available
Ventilation defect percent (VDP) measured in asthmatics with hyperpolarized helium-3 MRI was more strongly associated with ED visits and hospitalizations due to asthma exacerbation than were conventional biomarkers of lung function and inflammation.
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Introduction Quantitative CT (QCT) imaging-based metrics have quantified disease alterations in asthma and chronic obstructive pulmonary disease (COPD), respectively. We seek to characterise the similarity and disparity between these groups using QCT-derived airway and parenchymal metrics. Methods Asthma and COPD subjects (former-smoker status) we...
Article
Hyperpolarized 13C magnetic resonance imaging (MRI) may be used to non-invasively image the transport and chemical conversion of 13C–labeled compounds in vivo. In this study, we utilize hyperpolarized 13C MRI to evaluate metabolic markers in the kidneys longitudinally in a mouse model of partial unilateral ureteral obstruction (pUUO). Partial obstr...
Article
Full-text available
Rationale and objectives: To determine lobar ventilation patterns in asthmatic lungs with hyperpolarized 3He magnetic resonance imaging (HP 3He MRI). Materials and methods: Eighty-two subjects (14 normal, 48 mild-to-moderate asthma, and 20 severe asthma) underwent HP 3He MRI, computed tomography (CT), and pulmonary function testing. After regist...
Article
Full-text available
Background: A previous study demonstrated the feasibility of using 3D radial ultrashort echo time (UTE) oxygen-enhanced MRI (UTE OE-MRI) for functional imaging of healthy human lungs. The repeatability of quantitative measures from UTE OE-MRI needs to be established prior to its application in clinical research. Purpose: To evaluate repeatabilit...
Article
In medical imaging, clinicians, researchers and technicians have begun to use 3D printing to create specialized phantoms to replace commercial ones due to their customizable and iterative nature. Presented here is the design of a 3D printed open source, reusable magnetic resonance imaging (MRI) phantom, capable of flood-filling, with removable samp...
Article
Purpose: To develop a chemical shift encoding (CSE) approach for fluorine-19 MRI of perfluorocarbons in the presence of multiple known fluorinated chemical species. Theory and methods: A multi-echo CSE technique is applied for spectral separation of the perfluorocarbon perfluoro-15-crown-5-ether (PFCE) and isoflurane (ISO) based on their chemica...
Article
Full-text available
Purpose To develop and evaluate a protocol for hyperpolarized helium-3 (HHe) ventilation magnetic resonance imaging (MRI) of the lungs of non-sedated infants and children. Materials and methods HHe ventilation MRI was performed on seven children ≤4 years old. Contiguous 2D–spiral helium-3 images were acquired sequentially with a scan time of ≤0.2...
Article
In the past decade, hyperpolarized (HP) contrast agents have been under active development for MRI applications to address the twin challenges of functional and quantitative imaging. Both HP helium (<sup>3</sup>He) and xenon (<sup>129</sup>Xe) gases have reached the stage where they are under study in clinical research. HP <sup>129</sup>Xe, in part...
Article
the unique environmental challenge to the pulmonary physiology from exposure to high altitudes may hold unique insights into regulation of pulmonary function under stress. For example, high-altitude pulmonary edema (HAPE) is a mysterious disease characterized by individual differences in response to
Article
Purpose: To demonstrate that ultrashort echo time (UTE) magnetic resonance imaging (MRI) can achieve computed tomography (CT)-like quantification of lung parenchyma in free-breathing, non-sedated neonates. Because infant CTs are used sparingly, parenchymal disease evaluation via UTE MRI has potential for translational impact. Materials and method...
Article
Background: Imaging variables including airway diameter, wall thickness and air-trapping have been found to be important metrics when differentiating severe asthmatics from nonsevere asthmatics and healthy subjects. Objective: The objective of this study was to identify imaging-based clusters and to explore the association of the clusters with exi...
Article
Full-text available
Purpose: Computed Tomography (CT) imaging of the lung, reported in Hounsfield Units (HU), can be parameterized as a quantitative image biomarker for the diagnosis and monitoring of lung density changes due to emphysema, a type of chronic obstructive pulmonary disease (COPD). CT lung density metrics are global measurements based on lung CT number h...
Chapter
This chapter explores the application of magnetic resonance imaging (MRI) to the study of asthma with an emphasis on the role of hyperpolarized (HP) gases. Asthma affects millions of people worldwide and trends indicate increasing incidence particularly among children. In the first three sections of the chapter we focus on a general overview of ast...
Article
Asthma is a disease with significant clinical impact and growing incidence, particularly in children. It is characterized by a complex interplay of environmental and genetic factors that affect airway structure and function, leading to recurrent and spatially heterogeneous airway obstruction. Conventional methods for evaluating lung function using...
Article
In the last two decades, functional imaging of the lungs using hyperpolarized noble gases has entered the clinical stage. Both helium (³He) and xenon (¹²⁹Xe) gas have been thoroughly investigated for their ability to assess both the global and regional patterns of lung ventilation. With advances in polarizer technology and the current transition to...
Article
Full-text available
Rationale: Reducing asthma exacerbation frequency is an important criterion for approval of asthma therapies, but the clinical features of exacerbation-prone asthma (EPA) remain incompletely defined. Objectives: To describe the clinical, physiologic, inflammatory, and comorbidity factors associated with EPA. Methods: Baseline data from the NHL...