3D patient-specific models for left atrium characterization to support ablation in atrial fibrillation patients
In this study we propose a unified, fully automated approach to build a 3D patient-specific left atrium (LA) model including pulmonary veins (PVs) in order to provide an accurate anatomical guide during RFA and without PVs in order to characterize LA volumetry and support patient selection for AF ablation. (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 25, 2017 Category: Radiology Authors: Maddalena Valinoti, Claudio Fabbri, Dario Turco, Roberto Mantovan, Antonio Pasini, Cristiana Corsi Tags: Original contribution Source Type: research
Structural impacts on the timing and amplitude of the negative BOLD response
The positive (PBR) and negative BOLD responses (NBR) arising in task-fMRI display varying magnitudes and dynamics across voxels. While the effects of structure, particularly of veins, on the PBR have been studied, little is known of NBR-structure relationships. Like the PBR, the NBR is often used as a surrogate marker of neuronal activation in both basic and clinical research and assessing its relationship with cortical structure may help interpret group differences. We therefore investigated how local structure affects BOLD amplitude and timing in PBR and NBR areas using multi-band fMRI during visual stimulation to obtain...
Source: Magnetic Resonance Imaging - September 13, 2017 Category: Radiology Authors: David Provencher, Alexandre Bizeau, Guillaume Gilbert, Yves B érubé-Lauzière, Kevin Whittingstall Tags: Original contribution Source Type: research
A minimum-phase Shinnar-Le Roux spectral-spatial excitation RF pulse for simultaneous water and lipid suppression in 1H-MRSI of body extremities
To develop a spectral-spatial (SPSP) excitation RF pulse for simultaneous water and lipid suppression in proton (1H) magnetic resonance spectroscopic imaging (MRSI) of body extremities. (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 13, 2017 Category: Radiology Authors: Paul Kyu Han, Chao Ma, Kexin Deng, Shuang Hu, Kyung-Wook Jee, Kui Ying, Yen-Lin Chen, Georges El Fakhri Tags: Original contribution Source Type: research
A new RF transmit coil for foot and ankle imaging at 7T MRI
A four-channel Tic-Tac-Toe (TTT) transmit RF coil was designed and constructed for foot and ankle imaging at 7T MRI. Numerical simulations using an in-house developed FDTD package and experimental analyses using a homogenous phantom show an excellent agreement in terms of B1+ field distribution and s-parameters. Simulations performed on an anatomically detailed human lower leg model demonstrated an B1+ field distribution with a coefficient of variation (CV) of 23.9%/15.6%/28.8% and average B1+ of 0.33 μT/0.56μT/0.43μT for 1W input power (i.e., 0.25W per channel) in the ankle/calcaneus/mid foot respectively. (Source: Mag...
Source: Magnetic Resonance Imaging - September 8, 2017 Category: Radiology Authors: Tales Santini, Junghwan Kim, Sossena Wood, Narayanan Krishnamurthy, Nadim Farhat, Carlos Maciel, Shailesh Raval, Tiejun Zhao, Tamer Ibrahim Tags: Original contribution Source Type: research
Design strategies for improved velocity-selective pulse sequences
Over the years, a variety of MRI methods have been developed for visualizing or measuring blood flow without the use of contrast agents. One particular class of methods uses flow-encoding gradients associated with an RF pulse sequence to distinguish spins in flowing blood from stationary spins. While a strength of these particular methods is that, in general, they can be tailored to capture a desired range of blood flow, such sequences either do not provide a sharp transition from stationary spins to flowing spins, or else are long, generating relaxation losses and undesirable SAR, and have limited immunity to resonance of...
Source: Magnetic Resonance Imaging - September 7, 2017 Category: Radiology Authors: Gerald B. Matson Tags: Original contribution Source Type: research
Test-retest reliability of cerebral blood flow in healthy individuals using arterial spin labeling: Findings from the EMBARC study
Previous investigations of test-retest reliability of cerebral blood flow (CBF) at rest measured with pseudo-continuous Arterial Spin Labeling (pCASL) demonstrated good reliability, but are limited by the use of similar scanner platforms. In the present study we examined test-retest reliability of CBF in regions implicated in emotion and the default mode network. (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 6, 2017 Category: Radiology Authors: Jorge R.C. Almeida, Tsafrir Greenberg, Hanzhang Lu, Henry W. Chase, Jay Fournier, Crystal M. Cooper, Thilo Deckersbach, Phil Adams, Thomas Carmody, Mauricio Fava, Benji Kurian, Patrick J. McGrath, Melvin McInnis, Maria A. Oquendo, Ramin Parsey, Myrna Weis Tags: Original contribution Source Type: research
Inter-vender and test-retest reliabilities of resting-state functional magnetic resonance imaging: Implications for multi-center imaging studies
This prospective multi-center study aimed to evaluate the inter-vendor and test-retest reliabilities of resting-state functional magnetic resonance imaging (RS-fMRI) by assessing the temporal signal-to-noise ratio (tSNR) and functional connectivity. Study included 10 healthy subjects and each subject was scanned using three 3T MR scanners (GE Signa HDxt, Siemens Skyra, and Philips Achieva) in two sessions. The tSNR was calculated from the time course data. Inter-vendor and test-retest reliabilities were assessed with intra-class correlation coefficients (ICCs) derived from variant component analysis. (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 6, 2017 Category: Radiology Authors: Hyeong Su An, Won-Jin Moon, Jae-Kyun Ryu, Ju Yeon Park, Won Sung Yun, Jin Woo Choi, Geon-Ho Jahng, Jang-Yeon Park Tags: Original contribution Source Type: research
Extent of size, shape and systolic variability of the left ventricular outflow tract in aortic stenosis determined by phase-contrast MRI
Left ventricular outflow tract (LVOT) dimensions are important for calculation of aortic valve areas and planning of valve repair. Mostly, LVOT areas are calculated from echocardiographic longitudinal measurements with the assumption of a round shape. Here, orthogonal phase contrast (PC) MRI with dynamic assessment of LVOT was compared to standard longitudinal cine MRI and 2D echocardiography. (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 5, 2017 Category: Radiology Authors: Florian Sagmeister, Markus Weininger, Sebastian Herrmann, Peter Bernhardt, Volker Rasche, Robert Bauernschmitt, Andreas Liebold, Herbert K östler, Frank Weidemann, Meinrad Beer Tags: Original contribution Source Type: research
Reproducibility and relative stability in magnetic resonance imaging indices of tumor vascular physiology over a period of 24h in a rat 9L gliosarcoma model
The objective was to study temporal changes in tumor vascular physiological indices in a period of 24h in a 9L gliosarcoma rat model. (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 5, 2017 Category: Radiology Authors: Tavarekere N. Nagaraja, Rasha Elmghirbi, Stephen L. Brown, Lonni R. Schultz, Ian Y. Lee, Kelly A. Keenan, Swayamprava Panda, Glauber Cabral, Tom Mikkelsen, James R. Ewing Tags: Original contribution Source Type: research
Reduced distortion artifact whole brain CBF mapping using blip-reversed non-segmented 3D echo planar imaging with pseudo-continuous arterial spin labeling
To implement and evaluate interleaved blip-up, blip-down, non-segmented 3D echo planar imaging (EPI) with pseudo-continuous arterial spin labeling (pCASL) and post-processing for reduced susceptibility artifact cerebral blood flow (CBF) maps. (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 1, 2017 Category: Radiology Authors: Neville D. Gai, Yi Yu Chou, Dzung Pham, John A. Butman Tags: Original contribution Source Type: research
Reduced distortion artifact whole brain CBF mapping using blip-reversed 3D echo planar imaging with pseudo-continuous arterial spin labeling
To implement and evaluate interleaved blip-up, blip-down non-segmented 3D echo planar imaging (EPI) with pseudo-continuous arterial spin labeling (pCASL) and post-processing for reduced susceptibility artifact cerebral blood flow (CBF) maps. (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 1, 2017 Category: Radiology Authors: Neville D. Gai, Yi Yu Chou, Dzung Pham, John A. Butman Tags: Original contribution Source Type: research
COnstrained Data Extrapolation (CODE): A new approach for high definition vascular imaging from low resolution data
To introduce a new approach to reconstruct high definition vascular images using COnstrained Data Extrapolation (CODE) and evaluate its capability in estimating vessel area and stenosis. (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 1, 2017 Category: Radiology Authors: Yang Song, Ehsan Hamtaei, Sean K. Sethi, Guang Yang, Haibin Xie, E. Mark Haacke Tags: Original contribution Source Type: research
The development and optimisation of 3D black-blood R2* mapping of the carotid artery wall
To develop and optimise a 3D black-blood R2* mapping sequence for imaging the carotid artery wall, using optimal blood suppression and k-space view ordering. (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 1, 2017 Category: Radiology Authors: Jianmin Yuan, Martin J. Graves, Andrew J. Patterson, Andrew N. Priest, Pascal P.R. Ruetten, Ammara Usman, Jonathan H. Gillard Tags: Original contribution Source Type: research
Microstructure-informed slow diffusion tractography in humans enhances visualisation of fibre pathways
Conventional fibre tractography methods based on diffusion tensor imaging exploit diffusion anisotropy and directionality in the range of low diffusion weightings (b-values). High b-value Biexponential Diffusion Tensor Analysis reported previously has demonstrated that fractional anisotropy of the slow diffusion component is essentially higher than that of conventional diffusion tensor imaging whereas popular compartment models associate this slow diffusion component with axonal water fraction. One of the primary aims of this study is to elucidate the feasibility and potential benefits of “microstructure-informed” whol...
Source: Magnetic Resonance Imaging - September 1, 2017 Category: Radiology Authors: Farida Grinberg, Ivan I. Maximov, Ezequiel Farrher, N. Jon Shah Source Type: research
MRI protocol optimization for quantitative DCE-MRI of the spine
In this study we systematically investigated different Dynamic Contrast Enhancement (DCE)-MRI protocols in the spine, with the goal of finding an optimal protocol that provides data suitable for quantitative pharmacokinetic modelling (PKM). (Source: Magnetic Resonance Imaging)
Source: Magnetic Resonance Imaging - September 1, 2017 Category: Radiology Authors: Cristina Lavini, Gem Kramer, Indra Pieters-den Bos, Otto Hoekstra, J. Tim Marcus Source Type: research
