Publications by authors named "Stanley J Kruger"
Purpose: To introduce a new approach called tailored variable flip-angle (VFA) scheduling for SNR-efficient 3D T mapping of the brain using a magnetization-prepared gradient-echo sequence.
Methods: Simulations were used to assess the relative SNR efficiency, quantitative accuracy, and spatial blurring of tailored VFA scheduling for T mapping of brain tissue compared with magnetization-prepared angle-modulated partitioned k-space spoiled gradient-echo snapshots (MAPSS), a state-of-the-art technique for accurate 3D gradient-echo T mapping. Simulations were also used to calculate optimal imaging parameters for tailored VFA scheduling versus MAPSS, without and with nulling of CSF.
Article Synopsis
- The study aimed to examine how air flows in different parts of the lungs of asthmatics using a special imaging technique called hyperpolarized helium MRI.
- It involved 82 people, categorized based on their asthma severity, who underwent imaging and testing, allowing researchers to analyze ventilation in each lung lobe.
- Results revealed that asthma patients exhibited more ventilation issues in the right upper and middle lobes, whereas the lower lobes showed better ventilation, indicating important patterns that could improve targeted asthma treatment.
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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- The study assesses the repeatability of 3D radial ultrashort echo time (UTE) oxygen-enhanced MRI for detecting lung function patterns in conditions like asthma and cystic fibrosis.
- It involves 18 participants (5 with asthma, 6 with cystic fibrosis, and 7 healthy) and compares measurements taken under normal and high-oxygen conditions, using advanced imaging techniques and statistical analysis.
- Results show significant differences in ventilation metrics between normal subjects and those with asthma and cystic fibrosis, with notable correlations between MRI findings and traditional spirometry measures.
Rationale And Objectives: This study aimed to compare the performance of a semiautomated ventilation defect segmentation approach, adaptive K-means, with manual segmentation of hyperpolarized helium-3 magnetic resonance imaging in subjects with exercise-induced bronchoconstriction (EIB).
Materials And Methods: Six subjects with EIB underwent hyperpolarized helium-3 magnetic resonance imaging and spirometry tests at baseline, post exercise, and recovery over two separate visits. Ventilation defects were analyzed by two methods.
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).
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFPurpose: To investigate the utility of hyperpolarized He-3 MRI for detecting regional lung ventilated volume (VV) changes in response to exercise challenge and leukotriene inhibitor montelukast, human subjects with exercise induced bronchoconstriction (EIB) were recruited. This condition is described by airway constriction following exercise leading to reduced forced expiratory volume in 1 second (FEV1) coinciding with ventilation defects on hyperpolarized He-3 MRI.
Materials And Methods: Thirteen EIB subjects underwent spirometry and He-3 MRI at baseline, postexercise, and postrecovery at multiple visits.
Rationale: Air trapping and ventilation defects on imaging are characteristics of asthma. Airway wall thickening occurs in asthma and is associated with increased bronchial vascularity and vascular permeability. Vascular endothelial cell products have not been explored as a surrogate to mark structural airway changes in asthma.
View Article and Find Full Text PDFPurpose: To quantitatively evaluate interday, interreader, and intersite agreement of readers of hyperpolarized helium 3 (HPHe) MR images in patients with exercise-induced bronchoconstriction.
Materials And Methods: This HIPAA-compliant, institutional review board approved study included 13 patients with exercise-induced bronchoconstriction. On two separate days, HPHe MR imaging of the lungs was performed at baseline, immediately after a 10-minute exercise challenge (postchallenge), and 45 minutes after exercise (recovery).