139 research outputs found
sj-pdf-1-jcb-10.1177_0271678X211048031 - Supplemental material for Brain oxygen extraction fraction mapping in patients with multiple sclerosis
No full textSupplemental material, sj-pdf-1-jcb-10.1177_0271678X211048031 for Brain oxygen extraction fraction mapping in patients with multiple sclerosis by Junghun Cho, Thanh D Nguyen, Weiyuan Huang, Elizabeth M Sweeney, Xianfu Luo, Ilhami Kovanlikaya, Shun Zhang, Kelly M Gillen, Pascal Spincemaille, Ajay Gupta, Susan A Gauthier and Yi Wang in Journal of Cerebral Blood Flow & Metabolism</p
BOLD New Directions in Myocardial Ischemia Imaging–Myocardial Oxygenation Assessment by Cardiac Magnetic Resonance⁎⁎Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
No full textBrain Iron Distribution after Multiple Doses of Ultra-small Superparamagnetic Iron Oxide Particles in Rats
No full textThe purpose of this study is to determine the effects of high cumulative doses of ultra-small paramagnetic iron oxide (USPIO) used in neuroimaging studies. We intravenously administered 8 mg/kg of 2 USPIO compounds daily for 4 wk to male Sprague-Dawley rats (Crl:SD). Multiecho gradient-echo MRI, serum iron levels, and histology were performed at the end of dosing and after a 7-d washout period. R2 maps and quantitative susceptibility maps (QSM) were generated from multiecho gradient-echo data. R2 maps and QSM showed iron accumulation in brain ventricles on MR images acquired at the 4- and 5-wk time points. Estimates from QSM data showed ventricular iron concentration was equal to or higher than serum iron concentration. Histologic analysis revealed choroid plexus hemosiderosis and midbrain vacuolation, without iron deposition in brain parenchyma. Serum iron levels increased with administration of both compounds, and a 7-d washout period effectively reduced serum iron levels of one but not both of the compounds. High cumulative doses from multiple, frequent administrations of USPIO can lead to iron deposition in brain ventricles, resulting in persistent signal loss on T2 -weighted images. Techniques such as QSM are helpful in quantifying iron biodistribution in this situation
Brain Iron Distribution after Multiple Doses of Ultra-small Superparamagnetic Iron Oxide Particles in Rats
No full textThe purpose of this study is to determine the effects of high cumulative doses of ultra-small paramagnetic iron oxide (USPIO) used in neuroimaging studies. We intravenously administered 8 mg/kg of 2 USPIO compounds daily for 4 wk to male Sprague-Dawley rats (Crl:SD). Multiecho gradient-echo MRI, serum iron levels, and histology were performed at the end of dosing and after a 7-d washout period. R2 maps and quantitative susceptibility maps (QSM) were generated from multiecho gradient-echo data. R2 maps and QSM showed iron accumulation in brain ventricles on MR images acquired at the 4- and 5-wk time points. Estimates from QSM data showed ventricular iron concentration was equal to or higher than serum iron concentration. Histologic analysis revealed choroid plexus hemosiderosis and midbrain vacuolation, without iron deposition in brain parenchyma. Serum iron levels increased with administration of both compounds, and a 7-d washout period effectively reduced serum iron levels of one but not both of the compounds. High cumulative doses from multiple, frequent administrations of USPIO can lead to iron deposition in brain ventricles, resulting in persistent signal loss on T2 -weighted images. Techniques such as QSM are helpful in quantifying iron biodistribution in this situation
Recommended implementation of quantitative susceptibility mapping for clinical research in the brain: A consensus of the ISMRM electro‐magnetic tissue properties study group
No full textThis article provides recommendations for implementing QSM for clinical brain research. It is a consensus of the International Society of Magnetic Resonance in Medicine, Electro-Magnetic Tissue Properties Study Group. While QSM technical development continues to advance rapidly, the current QSM methods have been demonstrated to be repeatable and reproducible for generating quantitative tissue magnetic susceptibility maps in the brain. However, the many QSM approaches available have generated a need in the neuroimaging community for guidelines on implementation. This article outlines considerations and implementation recommendations for QSM data acquisition, processing, analysis, and publication. We recommend that data be acquired using a monopolar 3D multi-echo gradient echo (GRE) sequence and that phase images be saved and exported in Digital Imaging and Communications in Medicine (DICOM) format and unwrapped using an exact unwrapping approach. Multi-echo images should be combined before background field removal, and a brain mask created using a brain extraction tool with the incorporation of phase-quality-based masking. Background fields within the brain mask should be removed using a technique based on SHARP or PDF, and the optimization approach to dipole inversion should be employed with a sparsity-based regularization. Susceptibility values should be measured relative to a specified reference, including the common reference region of the whole brain as a region of interest in the analysis. The minimum acquisition and processing details required when reporting QSM results are also provided. These recommendations should facilitate clinical QSM research and promote harmonized data acquisition, analysis, and reporting
GAMER MRI: Gated-attention mechanism ranking of multi-contrast MRI in brain pathology
No full textDuring the last decade, a multitude of novel quantitative and semiquantitative MRI techniques have provided new information about the pathophysiology of neurological diseases. Yet, selection of the most relevant contrasts for a given pathology remains challenging. In this work, we developed and validated a method, Gated-Attention MEchanism Ranking of multi-contrast MRI in brain pathology (GAMER MRI), to rank the relative importance of MR measures in the classification of well understood ischemic stroke lesions. Subsequently, we applied this method to the classification of multiple sclerosis (MS) lesions, where the relative importance of MR measures is less understood
Recommended Implementation of Quantitative Susceptibility Mapping for Clinical Research in The Brain: A Consensus of the ISMRM Electro-Magnetic Tissue Properties Study Group
No full textExample datasets and code for the recommended implementation of Quantitative Susceptibility Mapping (QSM) in "Recommended Implementation of Quantitative Susceptibility Mapping for Clinical Research in The Brain: A Consensus of the ISMRM Electro-Magnetic Tissue Properties Study Group"
Attenuation of motion artifacts in fMRI using discrete reconstruction of irregular fMRI trajectories (DRIFT)
No full textCardiac fat navigator‐gated steady‐state free precession 3D magnetic resonance angiography of coronary arteries
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