Read by QxMD icon Read


Engin Baysoy, Dursun Korel Yildirim, Cagla Ozsoy, Senol Mutlu, Ozgur Kocaturk
No abstract text is available yet for this article.
October 12, 2016: Magma
Jason Langley, Daniel E Huddleston, Christine J Liu, Xiaoping Hu
OBJECTIVES: The purpose of this study was to assess the reproducibility of substantia nigra pars compacta (SNpc) and locus coeruleus (LC) delineation and measurement with neuromelanin-sensitive MRI. MATERIALS AND METHODS: Eleven subjects underwent two neuromelanin-sensitive MRI scans. SNpc and LC volumes were extracted for each scan. Reproducibility of volume and magnetization transfer contrast measurements in SNpc and LC was assessed using intraclass correlation coefficients (ICC) and dice similarity coefficients (DSC)...
September 29, 2016: Magma
Roberta Fusco, Mario Sansone, Antonella Petrillo
OBJECT: The objective of this study is to propose a modified VARiable PROjection (VARPRO) algorithm specifically tailored for fitting the intravoxel incoherent motion (IVIM) model to diffusion-weighted magnetic resonance imaging (DW-MRI) data from locally advanced rectal cancer (LARC). MATERIALS AND METHODS: The proposed algorithm is compared with classical non-linear least squares (NLLS) analysis using the Levenberg-Marquardt (LM) algorithm and with two recently proposed algorithms for 'segmented' analysis...
September 26, 2016: Magma
Faezeh Fallah, Jürgen Machann, Petros Martirosian, Fabian Bamberg, Fritz Schick, Bin Yang
OBJECTIVES: To evaluate and compare conventional T1-weighted 2D turbo spin echo (TSE), T1-weighted 3D volumetric interpolated breath-hold examination (VIBE), and two-point 3D Dixon-VIBE sequences for automatic segmentation of visceral adipose tissue (VAT) volume at 3 Tesla by measuring and compensating for errors arising from intensity nonuniformity (INU) and partial volume effects (PVE). MATERIALS AND METHODS: The body trunks of 28 volunteers with body mass index values ranging from 18 to 41...
September 16, 2016: Magma
Houchun H Hu, Amber L Pokorney, Niccolo Stefani, Jonathan M Chia, Jeffrey H Miller
OBJECTIVE: We demonstrate the potential clinical utility of a 4D non-gadolinium dynamic angiography technique based on arterial spin-labeling called contrast inherent inflow enhanced multi-phase angiography (CINEMA) in pediatric patients. MATERIALS AND METHODS: CINEMA was qualitatively compared to conventional time-of-flight (TOF) angiography in a cohort of 31 pediatric patients at 3 Tesla. RESULTS: CINEMA data were successfully acquired and reconstructed in all patients with no image artifacts...
September 13, 2016: Magma
Conrad Rockel, Alireza Akbari, Dinesh A Kumbhare, Michael D Noseworthy
OBJECT: To assess post-exercise recovery of human calf muscles using dynamic diffusion tensor imaging (dDTI). MATERIALS AND METHODS: DTI data (6 directions, b = 0 and 400 s/mm(2)) were acquired every 35 s from seven healthy men using a 3T MRI, prior to (4 volumes) and immediately following exercise (13 volumes, ~7.5 min). Exercise consisted of 5-min in-bore repetitive dorsiflexion-eversion foot motion with 0.78 kg resistance. Diffusion tensors calculated at each time point produced maps of mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity (RD), and signal at b = 0 s/mm(2) (S0)...
September 13, 2016: Magma
Engin Baysoy, Dursun Korel Yildirim, Cagla Ozsoy, Senol Mutlu, Ozgur Kocaturk
OBJECTIVES: A new microfabrication method to produce low profile radio frequency (RF) resonant markers on catheter shafts was developed. A semi-active RF resonant marker incorporating a solenoid and a plate capacitor was constructed on the distal shaft of a 5 Fr guiding catheter. The resulting device can be used for interventional cardiovascular MRI procedures. MATERIALS AND METHODS: Unlike current semi-active device visualization techniques that require rigid and bulky analog circuit components (capacitor and solenoid), we fabricated a low profile RF resonant marker directly on guiding the catheter surface by thin film metal deposition and electroplating processes using a modified physical vapor deposition system...
September 7, 2016: Magma
Edyta Blaszczyk, Agnieszka Töpper, Luisa Schmacht, Felix Wanke, Andreas Greiser, Jeanette Schulz-Menger, Florian von Knobelsdorff-Brenkenhoff
OBJECTIVE: Our aim was to study the influence of small variations in spatial resolution and contrast agent dosage on myocardial T1 relaxation time. MATERIALS AND METHODS: Twenty-nine healthy volunteers underwent cardiovascular magnetic resonance at 3T twice, including a modified look-locker inversion recovery (MOLLI) technique-3(3)3(3)5-for T1 mapping. Native T1 was assessed in three spatial resolutions (voxel size 1.4 × 1.4 × 6, 1.6 × 1.6 × 6, 1.7 × 1...
August 20, 2016: Magma
René-Maxime Gracien, Sarah C Reitz, Marlies Wagner, Christoph Mayer, Steffen Volz, Stephanie-Michelle Hof, Vinzenz Fleischer, Amgad Droby, Helmuth Steinmetz, Sergiu Groppa, Elke Hattingen, Johannes C Klein, Ralf Deichmann
OBJECTIVE: Proton density (PD) mapping requires correction for the receive profile (RP), which is frequently performed via bias-field correction. An alternative RP-mapping method utilizes a comparison of uncorrected PD-maps and a value ρ(T1) directly derived from T1-maps via the Fatouros equation. This may be problematic in multiple sclerosis (MS), if respective parameters are only valid for healthy brain tissue. We aimed to investigate whether the alternative method yields correct PD values in MS patients...
August 20, 2016: Magma
Monika Dezortova, Filip Jiru, Antonin Skoch, Vaclav Capek, Zuzana Ryznarova, Viktor Vik, Milan Hajek
OBJECTIVE: The effects of aging, magnetic field and the voxel localization on measured concentrations of citrate (Cit), creatine (Cr), cholines (Cho) and polyamines (PA) in a healthy prostate were evaluated. MATERIALS AND METHODS: 36 examinations at both 1.5T and 3T imagers of 52 healthy subjects aged 19-71 years were performed with PRESS 3D-CSI sequences (TE = 120 and 145 ms). Concentrations in laboratory units and their ratios to citrate were calculated using the LCModel technique...
August 13, 2016: Magma
James A Rioux, Steven D Beyea, Chris V Bowen
OBJECTIVE: Purely phase-encoded techniques such as single point imaging (SPI) are generally unsuitable for in vivo imaging due to lengthy acquisition times. Reconstruction of highly undersampled data using compressed sensing allows SPI data to be quickly obtained from animal models, enabling applications in preclinical cellular and molecular imaging. MATERIALS AND METHODS: TurboSPI is a multi-echo single point technique that acquires hundreds of images with microsecond spacing, enabling high temporal resolution relaxometry of large-R 2* systems such as iron-loaded cells...
August 8, 2016: Magma
Sergios Gatidis, Hansjörg Graf, Jakob Weiß, Alto Stemmer, Berthold Kiefer, Konstantin Nikolaou, Mike Notohamiprodjo, Petros Martirosian
OBJECTIVE: Our objective was to compare available techniques reducing artifacts in echo planar imaging (EPI)-based diffusion-weighed magnetic resonance imaging MRI (DWI) of the neck at 3 Tesla caused by B0-field inhomogeneities. MATERIALS AND METHODS: A cylindrical fat-water phantom was equipped with a Maxwell coil allowing for additional linear B0-field variations in z-direction. The effect of increasing strength of this superimposed gradient on image quality was observed using a standard single-shot EPI-based DWI sequence (sEPI), a zoomed single-shot EPI sequence (zEPI), a readout-segmented EPI sequence (rsEPI), and an sEPI sequence with integrated dynamic shimming (intEPI) on a 3-Tesla system...
August 8, 2016: Magma
Mads S Vinding, Daniel Brenner, Desmond H Y Tse, Sebastian Vellmer, Thomas Vosegaard, Dieter Suter, Tony Stöcker, Ivan I Maximov
OBJECTIVE: Ultrahigh field MRI provides great opportunities for medical diagnostics and research. However, ultrahigh field MRI also brings challenges, such as larger magnetic susceptibility induced field changes. Parallel-transmit radio-frequency pulses can ameliorate these complications while performing advanced tasks in routine applications. To address one class of such pulses, we propose an optimal-control algorithm as a tool for designing advanced multi-dimensional, large flip-angle, radio-frequency pulses...
August 2, 2016: Magma
Jorge Zavala Bojorquez, Stéphanie Bricq, François Brunotte, Paul M Walker, Alain Lalande
OBJECTIVE: To segment and classify the different attenuation regions from MRI at the pelvis level using the T 1 and T 2 relaxation times and anatomical knowledge as a first step towards the creation of PET/MR attenuation maps. MATERIALS AND METHODS: Relaxation times were calculated by fitting the pixel-wise intensities of acquired T 1- and T 2-weighted images from eight men with inversion-recovery and multi-echo multi-slice spin-echo sequences. A decision binary tree based on relaxation times was implemented to segment and classify fat, muscle, prostate, and air (within the body)...
October 2016: Magma
Maddalena Strumia, Wilfried Reichardt, Ori Staszewski, Dieter Henrik Heiland, Astrid Weyerbrock, Irina Mader, Michael Bock
OBJECTIVES: To differentiate between abnormal tumor vessels and regular brain vasculature using new quantitative measures in time-of-flight (TOF) MR angiography (MRA) data. MATERIALS AND METHODS: In this work time-of-flight (TOF) MR angiography data are acquired in 11 glioma patients to quantify vessel abnormality. Brain vessels are first segmented with a new algorithm, efficient monte-carlo image-analysis for the location of vascular entity (EMILOVE), and are then characterized in three brain regions: tumor, normal-appearing contralateral brain, and the total brain volume without the tumor...
October 2016: Magma
Christian Eberhardt, Moritz C Wurnig, Andrea Wirsching, Cristina Rossi, Markus Rottmar, Pinar S Özbay, Lukas Filli, Mickael Lesurtel, Andreas Boss
OBJECTIVE: Diffusion-weighted magnetic resonance imaging (DW-MRI) combined with intravoxel incoherent motion (IVIM) analysis may be applied for assessment of organ lesions, diffuse parenchymal pathologies, and therapy monitoring. The aim of this study was to determine IVIM reference parameters of abdominal organs for translational research in a large cohort of C57Bl/6 laboratory mice. MATERIALS AND METHODS: Anesthetized mice (n = 29) were measured in a 4.7 T small-animal MR scanner with a diffusion-weighted echo-planar imaging sequence at the [Formula: see text]-values 0, 13, 24, 55, 107, 260, 514, 767, 1020 s/mm(2)...
October 2016: Magma
Jana Taron, Petros Martirosian, Nina F Schwenzer, Michael Erb, Thomas Kuestner, Jakob Weiß, Ahmed Othman, Mike Notohamiprodjo, Konstantin Nikolaou, Christina Schraml
OBJECTIVE: To evaluate simultaneous multislice (sms) accelerated diffusion-weighted imaging (DWI) of the liver in comparison to conventional sequences. MATERIALS AND METHODS: Ten volunteers underwent DWI of the liver at 1.5 T. Four different sms-accelerated sequences with monopolar and bipolar gradient preparation (MP, BP) and acceleration factors 2 and 3 (sms2-DWI, sms3-DWI) were compared to conventional DWI (c-DWI). Image quality criteria rated on a 5-point Likert scale (5 = excellent), image quality sum scores (maximum 120), and ADC were compared using Friedman test and Dunn-Bonferroni post hoc test...
October 2016: Magma
Maryam Nezafat, Markus Henningsson, David P Ripley, Nathalie Dedieu, Gerald Greil, John P Greenwood, Peter Börnert, Sven Plein, René M Botnar
OBJECTIVES: To compare Dixon water-fat suppression with spectral pre-saturation with inversion recovery (SPIR) at 3T for coronary magnetic resonance angiography (MRA) and to demonstrate the feasibility of fat suppressed coronary MRA at 3T without administration of a contrast agent. MATERIALS AND METHODS: Coronary MRA with Dixon water-fat separation or with SPIR fat suppression was compared on a 3T scanner equipped with a 32-channel cardiac receiver coil. Eight healthy volunteers were examined...
October 2016: Magma
Yu Xin Yang, Mei Sian Chong, Laura Tay, Suzanne Yew, Audrey Yeo, Cher Heng Tan
OBJECTIVES: To develop and validate a machine learning based automated segmentation method that jointly analyzes the four contrasts provided by Dixon MRI technique for improved thigh composition segmentation accuracy. MATERIALS AND METHODS: The automatic detection of body composition is formulized as a three-class classification issue. Each image voxel in the training dataset is assigned with a correct label. A voxel classifier is trained and subsequently used to predict unseen data...
October 2016: Magma
(no author information available yet)
No abstract text is available yet for this article.
September 2016: Magma
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"