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Magnetic Resonance Imaging

Katherine L Wright, Yun Jiang, Dan Ma, Douglas C Noll, Mark A Griswold, Vikas Gulani, Luis Hernandez-Garcia
In this study, the acquisition of ASL data and quantification of multiple hemodynamic parameters was explored using a Magnetic Resonance Fingerprinting (MRF) approach. A pseudo-continuous ASL labeling scheme was used with pseudo-randomized timings to acquire the MRF ASL data in a 2.5 min acquisition. A large dictionary of MRF ASL signals was generated by combining a wide range of physical and hemodynamic properties with the pseudo-random MRF ASL sequence and a two-compartment model. The acquired signals were matched to the dictionary to provide simultaneous quantification of cerebral blood flow, tissue time-to-peak, cerebral blood volume, arterial time-to-peak, B1 , and T1...
March 12, 2018: Magnetic Resonance Imaging
Naoki Ohno, Tosiaki Miyati, Shuto Suzuki, Hirohito Kan, Toshitaka Aoki, Yoshitaka Nakamura, Yuki Hiramatsu, Satoshi Kobayashi, Toshifumi Gabata
PURPOSE: To suppress olefinic signals and enable simultaneous and quantitative estimation of multiple functional parameters associated with water and lipid, we investigated a modified method using chemical shift displacement and recovery-based separation of lipid tissue (SPLIT) involving acquisitions with different inversion times (TIs), echo times (TEs), and b-values. MATERIALS AND METHODS: Single-shot diffusion echo-planar imaging (SSD-EPI) with multiple b-values (0-3000 s/mm2 ) was performed without fat suppression to separate water and lipid images using the chemical shift displacement of lipid signals in the phase-encoding direction...
March 12, 2018: Magnetic Resonance Imaging
Shotaro Kanao, Masako Kataoka, Mami Iima, Debra Masako Ikeda, Masakazu Toi, Kaori Togashi
OBJECTIVES: Benign and malignant inflammatory breast lesions demonstrate similar findings on both T2 weighted imaging (T2WI) and dynamic contrast enhanced (DCE) images. We hypothesized that benign inflammatory lesions might be differentiated form malignancies using a combination of apparent diffusion coefficient (ADC) values derived from diffusion weighted images (DWI) and T2WI. MATERIALS AND METHODS: We retrospectively reviewed 162 patients undergoing breast MRI (T2WI, DWI and DCE images) between 2008 and 2015 who had breast lesions with high T2WI signal intensity (High T2 SI) including 14 benign inflammatory lesions, 69 benign non-inflammatory lesions, 16 malignant inflammatory lesions and 63 malignant non-inflammatory lesions...
March 12, 2018: Magnetic Resonance Imaging
Heather T Whittaker, Shenghua Zhu, Domenico L Di Curzio, Richard Buist, Xin-Min Li, Suzanna Noy, Frances K Wiseman, Jonathan D Thiessen, Melanie Martin
Alzheimer's disease (AD) pathology causes microstructural changes in the brain. These changes, if quantified with magnetic resonance imaging (MRI), could be studied for use as an early biomarker for AD. The aim of our study was to determine if T1 relaxation, diffusion tensor imaging (DTI), and quantitative magnetization transfer imaging (qMTI) metrics could reveal changes within the hippocampus and surrounding white matter structures in ex vivo transgenic mouse brains overexpressing human amyloid precursor protein with the Swedish mutation...
March 12, 2018: Magnetic Resonance Imaging
Ingrid Boehm, Johannes T Heverhagen
Both iodinated contrast media and gadolinium-based contrast agents (GBCAs) can induce immediate hypersensitivity reactions. In addition, iodinated contrast media have been shown to be responsible for delayed or non-immediate reactions that occur 1 h up to several days following iodinated contrast medium-injection. Here we for the first time present a female patient who acquired a delayed reaction after the application of a gadolinium-based contrast agent.
March 11, 2018: Magnetic Resonance Imaging
Benjamin J Zimmerman, Austin T Mudd, Joanne E Fil, Ryan N Dilger, Bradley P Sutton
Accurate quantitative non-invasive assessments of arterial cerebral blood volume (aCBV) can greatly benefit the study of cerebral vascular health in both humans and in animal models. In recent years, progress has been made in the techniques available to quantify CBV with magnetic resonance imaging (MRI). Here, we compared a non-invasive technique, measuring inflowing vascular space occupancy with dynamic subtraction (iVASO-ds) with a contrast-based vascular space occupancy measurement in piglets. In addition, we measured how the iVASO-ds derived aCBV changed with piglet development from 4 weeks to 8 weeks...
March 11, 2018: Magnetic Resonance Imaging
R Keerthi Sravan, Sneha Potdar, Pavan Poojar, Ashok Kumar Reddy, Stefan Kroboth, Jon-Fredrik Nielsen, Maxim Zaitsev, Ramesh Venkatesan, Sairam Geethanath
PURPOSE: To provide a single open-source platform for comprehensive MR algorithm development inclusive of simulations, pulse sequence design and deployment, reconstruction, and image analysis. METHODS: We integrated the "Pulseq" platform for vendor-independent pulse programming with Graphical Programming Interface (GPI), a scientific development environment based on Python. Our integrated platform, Pulseq-GPI, permits sequences to be defined visually and exported to the Pulseq file format for execution on an MR scanner...
March 11, 2018: Magnetic Resonance Imaging
Marta Gómez-Sancho, Jussi Tohka, Vanessa Gómez-Verdejo
Alzheimer's Disease (AD) is a progressive neurological disorder in which the death of brain cells causes memory loss and cognitive decline. The identification of at-risk subjects yet showing no dementia symptoms but who will later convert to AD can be crucial for the effective treatment of AD. For this, Magnetic Resonance Imaging (MRI) is expected to play a crucial role. During recent years, several Machine Learning (ML) approaches to AD-conversion prediction have been proposed using different types of MRI features...
March 9, 2018: Magnetic Resonance Imaging
Alexandre Rodrigues Farias, Daniel de Castro Medeiros, Hermes Aguiar Magalhães, Márcio Flávio Dutra Moraes, Eduardo M A M Mendes
PURPOSE: To combine the technique of respiratory gating and compressed sensing (CS) with the objective of accelerating mouse abdominal magnetic resonance imaging (MRI). MATERIALS AND METHODS: To obtain the maximum acceleration, phase-encoding data from a phantom and mouse were obtained on a 4.7 Tesla scanner using the respiratory gating technique. The fully sampled data (FSD) were used to construct reference images and to provide samples to simulate retrospective undersampled data (UD) acquisition using respiratory gating...
March 8, 2018: Magnetic Resonance Imaging
Michael Carl, Yajun Ma, Jiang Du
PURPOSE: Off-resonance saturation (ORS) is a tool which can be used in ultrashort echo time (UTE) magnetic resonance imaging to selectively reduce short T2 signals. When these ORS prepared UTE images are subtracted from a non-suppressed UTE acquisition, the short T2 signals are highlighted. The aim of this paper is to develop a theoretical ORS model and optimize short T2 contrast. THEORY: Using a theoretical model the sequence parameters such as saturation flip angle and off-resonance frequency were optimized to maximize short T2 contrast...
March 8, 2018: Magnetic Resonance Imaging
Prasanna Parvathaneni, Vishwesh Nath, Justin A Blaber, Kurt G Schilling, Allison E Hainline, Ed Mojahed, Adam W Anderson, Bennett A Landman
Neurite Orientation Dispersion and Density Imaging (NODDI) has been gaining prominence for estimating multiple diffusion compartments from MRI data acquired in a clinically feasible time. To establish a pathway for adoption of NODDI in clinical studies, it is important to understand the sensitivity and reproducibility of NODDI metrics on empirical data in the context of acquisition protocol and brain anatomy. Previous studies addressed reproducibility across the 3 T scanners and within session and between subject reproducibility at 1...
March 8, 2018: Magnetic Resonance Imaging
Remy Klaassen, Oliver J Gurney-Champion, Johanna W Wilmink, Marc G Besselink, Marc R W Engelbrecht, Jaap Stoker, Aart J Nederveen, Hanneke W M van Laarhoven
BACKGROUND: In current oncological practice of pancreatic ductal adenocarcinoma (PDAC), there is a great demand for response predictors and markers for early treatment evaluation. In this study, we investigated the repeatability and the interaction of dynamic contrast enhanced (DCE) and T2* MRI in patients with advanced PDAC to enable for such evaluation using these techniques. MATERIALS & METHODS: 15 PDAC patients underwent two DCE, T2* and anatomical 3 T MRI sessions before start of treatment...
February 21, 2018: Magnetic Resonance Imaging
Vahid Malekian, Abbas Nasiraei Moghaddam, Mahdi Khajehim
A non-balanced (nb) SSFP-based fMRI method based on CE-FAST is presented to alleviate some shortcomings of high spatial-specificity techniques commonly used in high static magnetic fields. The proposed sequence does not suffer from the banding artifacts inherent to balanced (b) SSFP, has low geometrical distortions and SAR compared to spin-echo EPI, and in contrast to previous nbSSFP implementations, is applied at a TR, theoretically prescribed for the optimum contrast. Its non-balanced gradient was chosen to just dephase the unwanted signal component (2π dephasing per TR per voxel)...
February 18, 2018: Magnetic Resonance Imaging
Khushbu Agarwal, Uma Sharma, Sandeep Mathur, Vurthaluru Seenu, Rajinder Parshad, Naranamangalam R Jagannathan
PURPOSE: To evaluate the utility of fat fraction (FF) for the differentiation of different breast tissues and in various breast tumor subtypes using in vivo proton ( 1 H) magnetic resonance spectroscopy (MRS). METHODS: 1 H MRS was performed on 68 malignant, 35 benign, and 30 healthy volunteers at 1.5 T. Malignant breast tissues of patients were characterized into different subtypes based on the differences in the expression of hormone receptors and the FF was calculated...
February 14, 2018: Magnetic Resonance Imaging
Christiaan Hendrik Bas van Niftrik, Marco Piccirelli, Oliver Bozinov, Nicolai Maldaner, Catherine Strittmatter, Athina Pangalu, Antonios Valavanis, Luca Regli, Jorn Fierstra
Neurovascular coupling describes the cascade between neuronal activity and subsequent Blood-Oxygenation-Level-Dependent (BOLD) signal increase. Based on this premise, the correlation of this BOLD signal increase with a particular task, such as finger-tapping, is used to map neuronal activation. This signal increase may be dampened in brain areas exhibiting impaired cerebrovascular reactivity (BOLD-CVR), leading to false negative activation. Blood-oxygenation-level-dependent (BOLD) cerebrovascular reactivity (CVR) has also been used to optimize task evoked BOLD signal changes...
February 13, 2018: Magnetic Resonance Imaging
Tsuyoshi Matsuda, Hirohiko Kimura, Hiroyuki Kabasawa, Masayuki Kanamoto
On arterial spin-labeled (ASL) images, areas of bright intravascular signal will appear when the post labeling delay time is shorter than arterial transit time. Vascular suppression (VS) schemes reduce artefactual bright signal by dephasing intravascular labeled spins. However, existing VS methods, such as Motion-Sensitized Driven-Equilibrium (MSDE), decrease the uniformity of the signal intensity distribution and extend the echo time. The purpose of this study is to compare VS using a Delays Alternating with Nutation for Tailored Excitation (DANTE) preparation pulse, with MSDE for ASL imaging on a flow phantom and volunteer data...
February 12, 2018: Magnetic Resonance Imaging
Floris Groenendaal
No abstract text is available yet for this article.
February 6, 2018: Magnetic Resonance Imaging
Ravi Bansal, Bradley S Peterson
Identifying regional effects of interest in MRI datasets usually entails testing a priori hypotheses across many thousands of brain voxels, requiring control for false positive findings in these multiple hypotheses testing. Recent studies have suggested that parametric statistical methods may have incorrectly modeled functional MRI data, thereby leading to higher false positive rates than their nominal rates. Nonparametric methods for statistical inference when conducting multiple statistical tests, in contrast, are thought to produce false positives at the nominal rate, which has thus led to the suggestion that previously reported studies should reanalyze their fMRI data using nonparametric tools...
February 3, 2018: Magnetic Resonance Imaging
Lorne W Hofstetter, Desmond T B Yeo, W Thomas Dixon, Luca Marinelli, Thomas K Foo
A three-point image reconstruction method for internally referenced MR thermometry was developed. The technique exploits the fact that temperature-induced changes in the water resonance frequency are small relative to the chemical shift difference between water and fat signals. This property enabled the use of small angle approximations to derive an analytic phase-based fat-water separation method for MR thermometry. Ethylene glycol and cream cool-down experiments were performed to validate measurement technique...
February 2, 2018: Magnetic Resonance Imaging
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