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proton density MRI

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https://www.readbyqxmd.com/read/28318741/neonatal-magnetic-resonance-imaging-without-sedation-correlates-with-injury-severity-in-brachial-plexus-birth-palsy
#1
Andrea S Bauer, Peter Y Shen, Anna E Nidecker, Paul S Lee, Michelle A James
PURPOSE: Which infants with brachial plexus birth palsy (BPBP) should undergo microsurgical plexus reconstruction remains controversial. The current gold standard for the decision for plexus reconstruction is serial clinical examinations, but this approach obviates the possibility of early surgical treatment. We hypothesize that a new technique using 3-dimensional volumetric proton density magnetic resonance imaging (MRI) without sedation can evaluate the severity of BPBP injury earlier than serial clinical examinations...
March 16, 2017: Journal of Hand Surgery
https://www.readbyqxmd.com/read/28306556/metal-artifact-reduction-in-mri-based-cervical-cancer-intracavitary-brachytherapy
#2
Yuan James Rao, Jacqueline E Zoberi, Mo Kadbi, Perry W Grigsby, Jochen Cammin, Stacie L Mackey, Jose Garcia-Ramirez, S Murty Goddu, Julie K Schwarz, H Michael Gach
Magnetic resonance imaging (MRI) plays an increasingly important role in brachytherapy planning for cervical cancer. Yet, metal tandem, ovoid intracavitary applicators, and fiducial markers used in brachytherapy cause magnetic susceptibility artifacts in standard MRI. These artifacts may impact the accuracy of brachytherapy treatment and the evaluation of tumor response by misrepresenting the size and location of the metal implant, and distorting the surrounding anatomy and tissue. Metal artifact reduction sequences (MARS) with high bandwidth RF selective excitations and turbo spin-echo readouts were developed for MRI of orthopedic implants...
March 17, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28296979/feasibility-of-assessing-bone-matrix-and-mineral-properties-in-vivo-by-combined-solid-state-1h-and-31p-mri
#3
Xia Zhao, Hee Kwon Song, Alan C Seifert, Cheng Li, Felix W Wehrli
PURPOSE: To develop and evaluate an integrated imaging protocol for bone water and phosphorus quantification in vivo by solid-state 1H and 31P MRI. MATERIALS AND METHODS: All studies were HIPAA-compliant and were performed with institutional review board approval and written informed consent. Proton (1H) ultra-short echo-time (UTE) and phosphorus (31P) zero echo-time (ZTE) sequences were designed and implemented on a 3 T clinical MR scanner to quantify bone water and mineral in vivo...
2017: PloS One
https://www.readbyqxmd.com/read/28282807/radiological-pathological-correlation-in-alzheimer-s-disease-systematic-review-of-antemortem-magnetic-resonance-imaging-findings
#4
Caroline Dallaire-Théroux, Brandy L Callahan, Olivier Potvin, Stephan Saikali, Simon Duchesne
BACKGROUND: The standard method of ascertaining Alzheimer's disease (AD) remains postmortem assessment of amyloid plaques and neurofibrillary degeneration. Vascular pathology, Lewy bodies, TDP-43, and hippocampal sclerosis are frequent comorbidities. There is therefore a need for biomarkers that can assess these etiologies and provide a diagnosis in vivo. OBJECTIVE: We conducted a systematic review of published radiological-pathological correlation studies to determine the relationship between antemortem magnetic resonance imaging (MRI) and neuropathological findings in AD...
March 6, 2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28280105/measurement-of-the-distribution-of-ventilation-perfusion-ratios-in-the-human-lung-with-proton-mri-comparison-with-the-multiple-inert-gas-elimination-technique
#5
Rui Carlos Sá, Angela Cortney Henderson, Tatum S Simonson, Tatsuya J Arai, Harrieth Wagner, Rebecca J Theilmann, Peter D Wagner, Gordon Kim Prisk, Susan Roberta Hopkins
We have developed a novel functional proton magnetic resonance imaging (MRI) technique to measure regional ventilation-perfusion (VA/Q ) ratio in the lung. We conducted a comparison study of this technique in healthy subjects (n=7, age=42±16, Forced expiratory volume in 1 second=94% predicted), by comparing data measured using MRI to that obtained from the multiple inert gas elimination technique (MIGET). Regional ventilation measured in a sagittal lung slice using Specific Ventilation Imaging was combined with proton density measured using a fast gradient-echo sequence to calculate regional alveolar ventilation, registered with perfusion images acquired using arterial spin labeling, and divided on a voxel-by-voxel basis to obtain regional VA/Q ratio...
March 9, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28267360/a-pilot-comparative-study-of-quantitative-ultrasound-conventional-ultrasound-and-mri-for-predicting-histology-determined-steatosis-grade-in-adult-nonalcoholic-fatty-liver-disease
#6
Jeremy S Paige, Gregory S Bernstein, Elhamy Heba, Eduardo A C Costa, Marilia Fereirra, Tanya Wolfson, Anthony C Gamst, Mark A Valasek, Grace Y Lin, Aiguo Han, John W Erdman, William D O'Brien, Michael P Andre, Rohit Loomba, Claude B Sirlin
OBJECTIVE: The purpose of this study is to explore the diagnostic performance of two investigational quantitative ultrasound (QUS) parameters, attenuation coefficient and backscatter coefficient, in comparison with conventional ultrasound (CUS) and MRI-estimated proton density fat fraction (PDFF) for predicting histology-confirmed steatosis grade in adults with nonalcoholic fatty liver disease (NAFLD). SUBJECTS AND METHODS: In this prospectively designed pilot study, 61 adults with histology-confirmed NAFLD were enrolled from September 2012 to February 2014...
March 7, 2017: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/28257339/symri-of-the-brain-rapid-quantification-of-relaxation-rates-and-proton-density-with-synthetic-mri-automatic-brain-segmentation-and-myelin-measurement
#7
Akifumi Hagiwara, Marcel Warntjes, Masaaki Hori, Christina Andica, Misaki Nakazawa, Kanako Kunishima Kumamaru, Osamu Abe, Shigeki Aoki
Conventional magnetic resonance images are usually evaluated using the image signal contrast between tissues and not based on their absolute signal intensities. Quantification of tissue parameters, such as relaxation rates and proton density, would provide an absolute scale; however, these methods have mainly been performed in a research setting. The development of rapid quantification, with scan times in the order of 6 minutes for full head coverage, has provided the prerequisites for clinical use. The aim of this review article was to introduce a specific quantification method and synthesis of contrast-weighted images based on the acquired absolute values, and to present automatic segmentation of brain tissues and measurement of myelin based on the quantitative values, along with application of these techniques to various brain diseases...
March 3, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28241076/characterisation-of-liver-fat-in-the-uk-biobank-cohort
#8
Henry R Wilman, Matt Kelly, Steve Garratt, Paul M Matthews, Matteo Milanesi, Amy Herlihy, Micheal Gyngell, Stefan Neubauer, Jimmy D Bell, Rajarshi Banerjee, E Louise Thomas
Non-alcoholic fatty liver disease and the risk of progression to steatohepatitis, cirrhosis and hepatocellular carcinoma have been identified as major public health concerns. We have demonstrated the feasibility and potential value of measuring liver fat content by magnetic resonance imaging (MRI) in a large population in this study of 4,949 participants (aged 45-73 years) in the UK Biobank imaging enhancement. Despite requirements for only a single (≤3min) scan of each subject, liver fat was able to be measured as the MRI proton density fat fraction (PDFF) with an overall success rate of 96...
2017: PloS One
https://www.readbyqxmd.com/read/28240801/longitudinal-quantitative-mri-assessment-of-cortical-damage-in-multiple-sclerosis-a-pilot-study
#9
René-Maxime Gracien, Sarah C Reitz, Stephanie-Michelle Hof, Vinzenz Fleischer, Amgad Droby, Mathias Wahl, Helmuth Steinmetz, Sergiu Groppa, Ralf Deichmann, Johannes C Klein
PURPOSE: Quantitative MRI (qMRI) allows assessing cortical pathology in multiple sclerosis (MS) on a microstructural level, where cortical damage has been shown to prolong T1 -relaxation time and increase proton density (PD) compared to controls. However, the evolution of these changes in MS over time has not been investigated so far. In this pilot study we used an advanced method for the longitudinal assessment of cortical tissue change in MS patients with qMRI in comparison to cortical atrophy, as derived from conventional MRI...
February 27, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28240218/an-anthropomorphic-breathing-phantom-of-the-thorax-for-testing-new-motion-mitigation-techniques-for-pencil-beam-scanning-proton-therapy
#10
R L Perrin, M Zakova, M Peroni, K Bernatowicz, C Bikis, A K Knopf, S Safai, P Fernandez-Carmona, N Tscharner, D C Weber, T C Parkel, A J Lomax
Motion-induced range changes and incorrectly placed dose spots strongly affect the quality of pencil-beam-scanned (PBS) proton therapy, especially in thoracic tumour sites, where density changes are large. Thus motion-mitigation techniques are necessary, which must be validated in a realistic patient-like geometry. We report on the development and characterisation of a dynamic, anthropomorphic, thorax phantom that can realistically mimic thoracic motions and anatomical features for verifications of proton and photon 4D treatments...
March 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28237893/dynamic-nuclear-polarization-via-thermal-mixing-beyond-the-high-temperature-approximation
#11
W Th Wenckebach
Dynamic Nuclear Polarization (DNP) via the mechanism of thermal mixing has proven itself most powerful for the orientation of nuclear spins in polarized targets and hyperpolarization for magnetic resonance imaging (MRI). Unfortunately, theoretical descriptions of this mechanism have been limited to using-at least partially-the high temperature approximation, in which Boltzmann factors are expanded linearly. However, the high nuclear spin polarization required and obtained for these applications does not justify such approximations...
February 20, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28225357/robust-sound-speed-estimation-for-ultrasound-based-hepatic-steatosis-assessment
#12
Imbault Marion, Alex Faccinetto, Bruno-Felix Osmanski, Antoine Tissier, Thomas Deffieux, Jean-Luc Gennisson, Valerie Vilgrain, Mickael Tanter
Hepatic steatosis is a common condition, the prevalence of which is increasing along with non-alcoholic fatty liver disease (NAFLD). Currently, the most accurate noninvasive imaging method for diagnosing and quantifying hepatic steatosis is MRI, which estimates the Proton-Density Fat Fraction (PDFF) as a measure of fractional fat content. However, MRI suffers several limitations including cost, contra-indications and poor availability. Although conventional ultrasound is widely used by radiologists for hepatic steatosis assessment, it remains qualitative and operator dependent...
February 22, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28220268/anterolateral-ligament-expert-group-consensus-paper-on-the-management-of-internal-rotation-and-instability-of-the-anterior-cruciate-ligament-deficient-knee
#13
REVIEW
Bertrand Sonnery-Cottet, Matthew Daggett, Jean-Marie Fayard, Andrea Ferretti, Camilo Partezani Helito, Martin Lind, Edoardo Monaco, Vitor Barion Castro de Pádua, Mathieu Thaunat, Adrian Wilson, Stefano Zaffagnini, Jacco Zijl, Steven Claes
Purpose of this paper is to provide an overview of the latest research on the anterolateral ligament (ALL) and present the consensus of the ALL Expert Group on the anatomy, radiographic landmarks, biomechanics, clinical and radiographic diagnosis, lesion classification, surgical technique and clinical outcomes. A consensus on controversial subjects surrounding the ALL and anterolateral knee instability has been established based on the opinion of experts, the latest publications on the subject and an exchange of experiences during the ALL Experts Meeting (November 2015, Lyon, France)...
February 20, 2017: Journal of Orthopaedics and Traumatology: Official Journal of the Italian Society of Orthopaedics and Traumatology
https://www.readbyqxmd.com/read/28205347/robust-universal-nonrigid-motion-correction-framework-for-first-pass-cardiac-mr-perfusion-imaging
#14
Mitchel Benovoy, Matthew Jacobs, Farida Cheriet, Nagib Dahdah, Andrew E Arai, Li-Yueh Hsu
PURPOSE: To present and assess an automatic nonrigid image registration framework that compensates motion in cardiac magnetic resonance imaging (MRI) perfusion series and auxiliary images acquired under a wide range of conditions to facilitate myocardial perfusion quantification. MATERIALS AND METHODS: Our framework combines discrete feature matching for large displacement estimation with a dense variational optical flow formulation in a multithreaded architecture...
February 15, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28190853/high-snr-acquisitions-improve-the-repeatability-of-liver-fat-quantification-using-confounder-corrected-chemical-shift-encoded-mr-imaging
#15
Utaroh Motosugi, Diego Hernando, Curtis Wiens, Peter Bannas, Scott B Reeder
PURPOSE: To determine whether high signal-to-noise ratio (SNR) acquisitions improve the repeatability of liver proton density fat fraction (PDFF) measurements using confounder-corrected chemical shift-encoded magnetic resonance (MR) imaging (CSE-MRI). MATERIALS AND METHODS: Eleven fat-water phantoms were scanned with 8 different protocols with varying SNR. After repositioning the phantoms, the same scans were repeated to evaluate the test-retest repeatability. Next, an in vivo study was performed with 20 volunteers and 28 patients scheduled for liver magnetic resonance imaging (MRI)...
February 13, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28179167/mri-and-mrs-of-the-human-brain-at-magnetic-fields-of-14t-to-20t-technical-feasibility-safety-and-neuroscience-horizons
#16
Thomas F Budinger, Mark D Bird
The three goals of this paper are: 1) to evaluate the improvements in technology for increasing magnetic flux density (magnetic field) to 14T in the next few years and eventually to 20T; 2) to highlight neuroscience opportunities enabled by these advances; and, 3) to evaluate the physiological and biophysical effects associated with MRI at very high performance levels. Substantial recent advances in magnet technology including superconductor developments enable neuroscience goals that are not obtainable at contemporary magnetic fields...
February 5, 2017: NeuroImage
https://www.readbyqxmd.com/read/28177647/comprehensive-assessment-of-ankle-syndesmosis-injury-using-3d-isotropic-turbo-spin-echo-sequences-diagnostic-performance-compared-with-that-of-conventional-and-oblique-3-t-mri
#17
Minchul Kim, Yun Sun Choi, Min Sun Jeong, Mira Park, Tong Jin Chun, Jin Su Kim, Ki Won Young
OBJECTIVE: The objective of this study is to evaluate the diagnostic performance of 3D sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) sequences in the evaluation of ankle syndesmosis injuries, compared with that of conventional orthogonal MRI and oblique proton density-weighted turbo spin-echo (TSE) sequences performed with 3-T MRI. MATERIALS AND METHODS: This retrospective study included 98 patients with suspected ankle syndesmosis injuries who underwent both MRI and surgery...
February 8, 2017: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/28154532/whole-brain-magnetic-resonance-image-atlases-a-systematic-review-of-existing-atlases-and-caveats-for-use-in-population-imaging
#18
REVIEW
David Alexander Dickie, Susan D Shenkin, Devasuda Anblagan, Juyoung Lee, Manuel Blesa Cabez, David Rodriguez, James P Boardman, Adam Waldman, Dominic E Job, Joanna M Wardlaw
Brain MRI atlases may be used to characterize brain structural changes across the life course. Atlases have important applications in research, e.g., as registration and segmentation targets to underpin image analysis in population imaging studies, and potentially in future in clinical practice, e.g., as templates for identifying brain structural changes out with normal limits, and increasingly for use in surgical planning. However, there are several caveats and limitations which must be considered before successfully applying brain MRI atlases to research and clinical problems...
2017: Frontiers in Neuroinformatics
https://www.readbyqxmd.com/read/28141514/terahertz-imaging-of-cutaneous-edema-correlation-with-magnetic-resonance-imaging-in-burn-wounds
#19
Neha Bajwa, Shijun Sung, Daniel B Ennis, Michael C Fishbein, Bryan Nowroozi, Dan Ruan, Ashkan Maccabi, Jeffrey Alger, Maie A St John, Warren S Grundfest, Zachary D Taylor
OBJECTIVE: In vivo visualization and quantification of edema, or 'tissue swelling' following injury, remains a clinical challenge. Herein, we investigate the ability of reflective terahertz (THz) imaging to track changes in tissue water content (TWC) - the direct indicator of edema- by comparison to depth-resolved magnetic resonance imaging (MRI) in a burn-induced model of edema. METHODS: A partial thickness and full thickness burn were induced in an in vivo rat model to elicit unique TWC perturbations corresponding to burn severity...
January 26, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28121631/prediction-and-compensation-of-magnetic-beam-deflection-in-mr-integrated-proton-therapy-a-method-optimized-regarding-accuracy-versatility-and-speed
#20
Sonja M Schellhammer, Aswin L Hoffmann
The integration of magnetic resonance imaging (MRI) and proton therapy for on-line image-guidance is expected to reduce dose delivery uncertainties during treatment. Yet, the proton beam experiences a Lorentz force induced deflection inside the magnetic field of the MRI scanner, and several methods have been proposed to quantify this effect. We analyze their structural differences and compare results of both analytical and Monte Carlo models. We find that existing analytical models are limited in accuracy and applicability due to critical approximations, especially including the assumption of a uniform magnetic field...
February 21, 2017: Physics in Medicine and Biology
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