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2d echo

Desmond H Y Tse, Christopher J Wiggins, Benedikt A Poser
PURPOSE: In order to fully benefit from the improved signal-to-noise and contrast-to-noise ratios at 9.4T, the challenges of B1+ inhomogeneity and the long acquisition time of high-resolution 2D gradient-recalled echo (GRE) imaging were addressed. THEORY AND METHODS: Flip angle homogenized excitations were achieved by parallel transmission (pTx) of 3-spoke pulses, designed by magnitude least-squares optimization in a slice-by-slice fashion; the acquisition time reduction was achieved by simultaneous multislice (SMS) pulses...
October 23, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Stefano Strano, Alessandra Fanciulli, Massimiliano Rizzo, Paolo Marinelli, Paolo Palange, Dorina Tiple, Giuseppe De Vincentis, Giovanni Calcagnini, Federica Censi, Giuseppe Meco, Carlo Colosimo
BACKGROUND: The clinical presentation of Parkinson's disease (PD) includes a wide spectrum of non-motor features, including cardiovascular autonomic failure. OBJECTIVE: To evaluate cardiovascular autonomic status and cardiac functional capacity in drug-naïve PD patients. METHODS: 18 newly-diagnosed PD patients underwent laboratory cardiovascular autonomic function tests using power spectral analysis of the R-R interval, blood pressure (BP) short-term variability and non-invasive baroreflex sensitivity (BRS)...
November 15, 2016: Journal of the Neurological Sciences
Takashi Hashido, Shigeyoshi Saito
PURPOSE: Neuromelanin is a dark pigment granule present within certain catecholamine neurons of the human brain. Here, we aimed to clarify the relationship between contrast of neuromelanin-sensitive magnetic resonance imaging (MRI) and MR relaxation times using T1, T2, and T2* mapping of the lower midbrain. METHODS: The subjects were 14 healthy volunteers (11 men and 3 women, mean age 29.9 ± 6.9 years). Neuromelanin-sensitive MRI was acquired using an optimized T1-weighted two-dimensional (2D)-turbo spin-echo sequence...
2016: PloS One
Grzegorz Bauman, Francesco Santini, Orso Pusterla, Oliver Bieri
PURPOSE: To present a technique for simultaneous mapping of T1 , T2 , and relative spin density (M0 ) in human lung using inversion recovery ultra-fast steady-state free precession (IR-ufSSFP) imaging. METHODS: Pulmonary relaxometry with IR-ufSSFP is based on an interleaved time series acquisition of 2D images acquired at 1.5T. The technique was tested in a phantom and in four healthy volunteers using breath-hold and electrocardiogram triggering. Typically, 30 transient state images were acquired in a single breath-hold within < 10 s...
October 19, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Massimo Salvetti, Anna Paini, Claudia Agabiti Rosei, Deborah Stassaldi, Fabio Bertacchini, Giulia Rubagotti, Giulia Maruelli, Laura Verzeri, Carlotta Donini, Maria Lorenza Muiesan, Enrico Agabiti Rosei
OBJECTIVE: The recent results of the SPRINT study suggest that "intensive" reduction of systolic blood pressure (BP) (to less than 120 mmHg) might provide greater cardiovascular protection as compared to less intensive (< 140 mmHg) reduction of BP, at least in some subsets of patients. Only few studies, have investigated the possible effect of tight blood pressure control on indices of left ventricular hypertrophy, and have been mainly based on electrocardiography. Aim of our study was to evaluate cardiac organ damage according to "on treatment" blood pressure values in a large cohort of hypertensive patients undergoing echocardiography (2D, M-mode with conventional and tissue Doppler analysis)at the echo-lab of an ESH Excellence Centre in Italy...
September 2016: Journal of Hypertension
Enrico Agabiti Rosei
Current Hypertension Guidelines emphasize the importance of assessing the presence of preclinical organ damage. In fact, an extensive evaluation of organ damage may increase the number of patients classified at high CV risk and therefore strongly influence the clinical management of patients. Hypertensive heart disease remains to date the form of organ damage for which there is the greatest amount of evidence of a strong independent prognostic significance. In the presence of a chronic pressure overload, a parallel addition of sarcomers takes place with an increase in myocyte width, which in turn increases left ventricular wall thickness; myocyte hypertrophy is also associated with apoptosis, collagen deposition and ventricular fibrosis with an impairment of coronary hemodynamics as well, thus profoundly influencing functional properties of the left (and right) ventricle...
September 2016: Journal of Hypertension
Faysal F Altahawi, Kevin J Blount, Nicholas P Morley, Esther Raithel, Imran M Omar
PURPOSE: To compare a faster, new, high-resolution accelerated 3D-fast-spin-echo (3D-FSE) acquisition sequence (CS-SPACE) to traditional 2D and high-resolution 3D sequences for knee 3-T magnetic resonance imaging (MRI). MATERIALS AND METHODS: Twenty patients received knee MRIs that included routine 2D (T1, PD ± FS, T2-FS; 0.5 × 0.5 × 3 mm(3); ∼10 min), traditional 3D FSE (SPACE-PD-FS; 0.5 × 0.5 × 0.5 mm(3); ∼7.5 min), and accelerated 3D-FSE prototype (CS-SPACE-PD-FS; 0...
October 15, 2016: Skeletal Radiology
Suma P Goudar, G Hamilton Baker, Shahryar M Chowdhury, Kimberly J Reid, Girish Shirali, Mark A Scheurer
BACKGROUND: Adult studies demonstrate that echocardiographic measurements of cardiac function using speckle tracking correlate with invasive measurements, but such data in the pediatric population are sparse. Our aim was to compare speckle-derived measures of cardiac function to measurements routinely obtained by cardiac catheterization in children. METHODS: Echocardiograms were performed on the day of cardiac catheterization. Using Tomtec 2D Cardiac Performance Analysis, longitudinal strain (LS), longitudinal strain rate (LSR), early diastolic LSR, and ejection fraction (EF) for the right and left ventricle (RV and LV) were calculated via speckle tracking...
October 14, 2016: Echocardiography
Christopher Piorkowski, Ole-A Breithardt, Hedi Razavi, Yelena Nabutovsky, Stuart P Rosenberg, Craig D Markovitz, Arash Arya, Sascha Rolf, Silke John, Jedrzej Kosiuk, Eric Olson, Charlotte Eitel, Yan Huo, Michael Döring, Sergio Richter, Kyungmoo Ryu, Thomas Gaspar, Frits W Prinzen, Gerhard Hindricks, Philipp Sommer
AIMS: In times of evolving cardiac resynchronization therapy, intra-procedural characterization of left ventricular (LV) mechanical activation patterns is desired but technically challenging with currently available technologies. In patients with normal systolic function, we evaluated the feasibility of characterizing LV wall motion using a novel sensor-based, real-time tracking technology. METHODS AND RESULTS: Ten patients underwent simultaneous motion and electrical mapping of the LV endocardium during sinus rhythm using electroanatomical mapping and navigational systems (EnSite™ NavX™ and MediGuide™, SJM)...
October 12, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
Chiara H Giammanco, Patrick L Kramer, Daryl B Wong, Michael D Fayer
The effects of water concentration and varying alkyl chain length on the dynamics of water in 1-alkyl-3-methylimidazolium tetrafluoroborate room temperature ionic liquids (RTILs) were characterized using two dimensional infrared (2D IR) vibrational echo spectroscopy and polarization-selective IR pump-probe experiments to study the water hydroxyl (OD) stretching mode of dilute HOD in H2O. Three imidazolium cation alkyl chain lengths, ethyl (Emim), butyl (Bmim), and decyl (Dmim), were investigated. Both the Bmim and Dmim cations have sufficiently long chains that the liquids exhibit polar-apolar segregation, while the Emim ionic liquid has no significant apolar aggregation...
October 11, 2016: Journal of Physical Chemistry. B
Shanshan Bao, Jonathan I Tamir, Jeffrey L Young, Umar Tariq, Martin Uecker, Peng Lai, Weitian Chen, Michael Lustig, Shreyas S Vasanawala
PURPOSE: To develop and clinically evaluate a pediatric knee magnetic resonance imaging (MRI) technique based on volumetric fast spin-echo (3DFSE) and compare its diagnostic performance, image quality, and imaging time to that of a conventional 2D protocol. MATERIALS AND METHODS: A 3DFSE sequence was modified and combined with a compressed sensing-based reconstruction resolving multiple image contrasts, a technique termed T2 Shuffling (T2 Sh). With Institutional Review Board (IRB) approval, 28 consecutive children referred for 3T knee MRI prospectively underwent a standard clinical knee protocol followed by T2 Sh...
October 11, 2016: Journal of Magnetic Resonance Imaging: JMRI
Suraj D Serai, Jonathan R Dillman, Andrew T Trout
Purpose To compare two-dimensional (2D) gradient-recalled echo (GRE) and 2D spin-echo (SE) echo-planar imaging (EPI) magnetic resonance (MR) elastography for measurement of hepatic stiffness in pediatric and young adult patients suspected of having liver disease. Materials and Methods In this institutional review board-approved, HIPAA-compliant study, 58 patients underwent both 2D GRE and 2D SE-EPI MR elastography at 1.5 T during separate breath holds. Liver stiffness (mean of means; in kilopascals) was measured by five blinded reviewers...
October 10, 2016: Radiology
Chi-Man Koon, Xin Zhang, Weitian Chen, Eagle Siu Hong Chu, Clara Bik San Lau, Yì-Xiáng J Wáng
BACKGROUND: To explore black blood T1rho (T1ρ) liver imaging and investigate the earliest stage when biliary duct ligation (BDL) induced liver fibrosis can be diagnosed. METHODS: MR was performed at 3 Tesla. A T1ρ prepared 2D fast spin echo (FSE) sequence with acquisition of four spin lock times (TSLs: 1, 10, 30, and 50 msec) and spin-lock frequency of 500 Hz was applied. Inherent black blood effect of FSE and double inversion recovery (DIR) achieved blood signal suppression, and 3 axial sections per liver were obtained...
August 2016: Quantitative Imaging in Medicine and Surgery
Alexandra S Gersing, Benedikt J Schwaiger, Ursula Heilmeier, Gabby B Joseph, Luca Facchetti, Martin Kretzschmar, John A Lynch, Charles E McCulloch, Michael C Nevitt, Lynne S Steinbach, Thomas M Link
OBJECTIVES: To evaluate the ability of different MRI sequences to detect chondrocalcinosis within knee cartilage and menisci, and to analyze the association with joint degeneration. METHODS: Subjects with radiographic knee chondrocalcinosis (n = 90, age 67.7 ± 7.3 years, 50 women) were selected from the Osteoarthritis Initiative and matched to controls without radiographic chondrocalcinosis (n = 90). Visualization of calcium-containing crystals (CaC) was compared between 3D T1-weighted gradient-echo (T1GE), 3D dual echo steady-state (DESS), 2D intermediate-weighted (IW), and proton density (PD)-weighted fast spin-echo (FSE) sequences obtained with 3T MRI and correlated with a semiquantitative CaC score obtained from radiographs...
October 4, 2016: European Radiology
Jian Lu, Yaqing Zhang, Harold Y Hwang, Benjamin K Ofori-Okai, Sharly Fleischer, Keith A Nelson
Ultrafast 2D spectroscopy uses correlated multiple light-matter interactions for retrieving dynamic features that may otherwise be hidden under the linear spectrum; its extension to the terahertz regime of the electromagnetic spectrum, where a rich variety of material degrees of freedom reside, remains an experimental challenge. We report a demonstration of ultrafast 2D terahertz spectroscopy of gas-phase molecular rotors at room temperature. Using time-delayed terahertz pulse pairs, we observe photon echoes and other nonlinear signals resulting from molecular dipole orientation induced by multiple terahertz field-dipole interactions...
October 4, 2016: Proceedings of the National Academy of Sciences of the United States of America
Anna I Blazejewska, Sharmishtaa Seshamani, Susan K McKown, Jason S Caucutt, Manjiri Dighe, Christopher Gatenby, Colin Studholme
PURPOSE: Maximization of the blood oxygen level-dependent (BOLD) functional MRI (fMRI) contrast requires the echo time of the MR sequence to match the T2* value of the tissue of interest, which is expected to be higher in the fetal brain compared with the brain of a child or an adult. METHODS: T2* values of the cortical plate/cortical gray matter tissue in utero in healthy fetuses from mid-gestation onward (20-36 gestational weeks) were measured using 3D T2* maps calculated from 2D dual-echo T2*-weighted data corrected for between-slice motion and reconstructed in 1...
October 3, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Hyungseok Jang, Alan B McMillan
PURPOSE: We propose a new gradient measurement technique based on dynamic single-point imaging (SPI), which allows simple, rapid, and robust measurement of k-space trajectory. METHODS: To enable gradient measurement, we utilize the variable field-of-view (FOV) property of dynamic SPI, which is dependent on gradient shape. First, one-dimensional (1D) dynamic SPI data are acquired from a targeted gradient axis, and then relative FOV scaling factors between 1D images or k-spaces at varying encoding times are found...
October 3, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Martin Lombardero, Ruth Henquin, Gabriel Perea, Mariana Corneli, Carlos Izurieta
INTRODUCTION: Quantification of mitral regurgitation (MR) by two-dimensional (2D) transthoracic echocardiography (TTE) is based on the analysis of the proximal flow convergence (PFC) and the "vena contracta" (VC). This method assumes geometries and can be misleading. In contrast, three-dimensional (3D) echocardiography directly measures flow volumes and does not assume geometries, which allows for more accurate MR evaluation. AIMS: To report the 3D transesophageal echocardiography (3DTEE) feasibility for MR quantification and evaluate its concordance with 2D echo...
October 4, 2016: Echocardiography
Hironobu Ito, Taisuke Hasegawa, Yoshitaka Tanimura
The low-frequency vibrational spectrum of liquid water is composed of contributions from the intermolecular librational and translation modes. The existence of these two modes introduces difficulty into the simulation of experimentally obtained Raman spectra. We constructed a polarizability function for a water model that includes intramolecular charge flow (CF) effects, intermolecular charge transfer (CT) effects, and intermolecular dipole-induced-dipole (DID) effects. We computed the one-dimensional (1D) Raman and terahertz (THz) spectra with all of these effects included (CFCT-DID) and compared with experimental spectra...
October 6, 2016: Journal of Physical Chemistry Letters
Xiaoling Zhang, Meizhi Li, Jian Guan, Huanjun Wang, Shurong Li, Yan Guo, Mingjuan Liu
PURPOSE: To investigate the feasibility of three-dimensional MR neurography (3D MRN) for the sacral plexus using sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) sequences, and to demonstrate structural abnormalities in the pelvic nerve of women with pelvic endometriosis. MATERIALS AND METHODS: Twenty patients with pelvic endometriosis and 20 healthy controls were examined by contrast-enhanced 3D short time inversion recovery T2-weighted imaging (CE 3D STIR T2WI) SPACE sequences on 3 Tesla MRI...
September 26, 2016: Journal of Magnetic Resonance Imaging: JMRI
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