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https://www.readbyqxmd.com/read/28433503/mr-fingerprinting-reconstruction-with-kalman-filter
#1
Xiaodi Zhang, Zechen Zhou, Shiyang Chen, Shuo Chen, Rui Li, Xiaoping Hu
Magnetic resonance fingerprinting (MR fingerprinting or MRF) is a newly introduced quantitative magnetic resonance imaging technique, which enables simultaneous multi-parameter mapping in a single acquisition with improved time efficiency. The current MRF reconstruction method is based on dictionary matching, which may be limited by the discrete and finite nature of the dictionary and the computational cost associated with dictionary construction, storage and matching. In this paper, we describe a reconstruction method based on Kalman filter for MRF, which avoids the use of dictionary to obtain continuous MR parameter measurements...
April 19, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28419591/application-of-spin-echoes-in-the-regime-of-weak-dephasing-to-t1-mapping-of-the-lung
#2
Jakob Assländer, Steffen J Glaser, Jürgen Hennig
PURPOSE: This work presents an approach to mapping the entire lung's proton density and T1 within a single breath-hold and analyzes the apparent T1 when exciting with a spin echo generating pulse in comparison to a standard gradient echo acquisition. METHODS: An inversion-recovery SNAPSHOT-FLASH sequence with a stack-of-stars k-space readout with a golden angle increment was modified to use a spin echo generating radiofrequency-pulse for excitation. Data of five volunteers were acquired on a 3T scanner and image reconstruction was performed by an iterative algorithm adopted from MR-Fingerprinting...
April 17, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28414052/spiral-mr-fingerprinting-at-7t-with-simultaneous-b1-estimation
#3
Guido Buonincontri, Rolf F Schulte, Mirco Cosottini, Michela Tosetti
Magnetic resonance fingerprinting is an efficient, new approach for quantitative imaging with MR. We aimed to extend this technique to cases with B1+ inhomogeneities within the imaging volume. Previous approaches have used abrupt changes in flip angles to estimate the B1+ field simultaneously with T1 and T2, using a Cartesian approach in a small-animal scanner at 4.7T. Here, we evaluated whether a similar approach would be suitable for imaging human brains using spiral readouts with a 7T scanner. We found that our modified scheme could significantly reduce the adverse effects of B1+ inhomogeneities even in extreme cases, reducing both the bias and the variance in T2 estimations by an order of magnitude when compared to literature methods...
April 13, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28412455/effects-of-rf-pulse-profile-and-intra-voxel-phase-dispersion-on-mr-fingerprinting-with-balanced-ssfp-readout
#4
Su-Chin Chiu, Te-Ming Lin, Jyh-Miin Lin, Hsiao-Wen Chung, Cheng-Wen Ko, Martin Büchert, Michael Bock
PURPOSE: To investigate possible errors in T1 and T2 quantification via MR fingerprinting with balanced steady-state free precession readout in the presence of intra-voxel phase dispersion and RF pulse profile imperfections, using computer simulations based on Bloch equations. MATERIALS AND METHODS: A pulse sequence with TR changing in a Perlin noise pattern and a nearly sinusoidal pattern of flip angle following an initial 180-degree inversion pulse was employed...
April 13, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28411394/improved-magnetic-resonance-fingerprinting-reconstruction-with-low-rank-and-subspace-modeling
#5
Bo Zhao, Kawin Setsompop, Elfar Adalsteinsson, Borjan Gagoski, Huihui Ye, Dan Ma, Yun Jiang, P Ellen Grant, Mark A Griswold, Lawrence L Wald
PURPOSE: This article introduces a constrained imaging method based on low-rank and subspace modeling to improve the accuracy and speed of MR fingerprinting (MRF). THEORY AND METHODS: A new model-based imaging method is developed for MRF to reconstruct high-quality time-series images and accurate tissue parameter maps (e.g., T1 , T2 , and spin density maps). Specifically, the proposed method exploits low-rank approximations of MRF time-series images, and further enforces temporal subspace constraints to capture magnetization dynamics...
April 15, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28391061/rf-slice-profile-effects-in-magnetic-resonance-fingerprinting
#6
Taehwa Hong, Dongyeob Han, Min-Oh Kim, Dong-Hyun Kim
The radio frequency (RF) slice profile effects on T1 and T2 estimation in magnetic resonance fingerprinting (MRF) are investigated with respect to time-bandwidth product (TBW), flip angle (FA) level and field inhomogeneities. Signal evolutions are generated incorporating the non-ideal slice selective excitation process using Bloch simulation and matched to the original dictionary with and without the non-ideal slice profile taken into account. For validation, phantom and in vivo experiments are performed at 3T...
April 5, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28328013/validation-of-surface-to-volume-ratio-measurements-derived-from-oscillating-gradient-spin-echo-on-a-clinical-scanner-using-anisotropic-fiber-phantoms
#7
Gregory Lemberskiy, Steven H Baete, Martijn A Cloos, Dmitry S Novikov, Els Fieremans
A diffusion measurement in the short-time surface-to-volume ratio (S/V) limit (Mitra et al., Phys Rev Lett. 1992;68:3555) can disentangle the free diffusion coefficient from geometric restrictions to diffusion. Biophysical parameters, such as the S/V of tissue membranes, can be used to estimate microscopic length scales non-invasively. However, due to gradient strength limitations on clinical MRI scanners, pulsed gradient spin echo (PGSE) measurements are impractical for probing the S/V limit. To achieve this limit on clinical systems, an oscillating gradient spin echo (OGSE) sequence was developed...
May 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28268369/optimal-experiment-design-for-magnetic-resonance-fingerprinting
#8
Bo Zhao, Justin P Haldar, Kawin Setsompop, Lawrence L Wald
Magnetic resonance (MR) fingerprinting is an emerging quantitative MR imaging technique that simultaneously acquires multiple tissue parameters in an efficient experiment. In this work, we present an estimation-theoretic framework to evaluate and design MR fingerprinting experiments. More specifically, we derive the Cramér-Rao bound (CRB), a lower bound on the covariance of any unbiased estimator, to characterize parameter estimation for MR fingerprinting. We then formulate an optimal experiment design problem based on the CRB to choose a set of acquisition parameters (e...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28261851/low-rank-alternating-direction-method-of-multipliers-reconstruction-for-mr-fingerprinting
#9
Jakob Assländer, Martijn A Cloos, Florian Knoll, Daniel K Sodickson, Jürgen Hennig, Riccardo Lattanzi
PURPOSE: The proposed reconstruction framework addresses the reconstruction accuracy, noise propagation and computation time for magnetic resonance fingerprinting. METHODS: Based on a singular value decomposition of the signal evolution, magnetic resonance fingerprinting is formulated as a low rank (LR) inverse problem in which one image is reconstructed for each singular value under consideration. This LR approximation of the signal evolution reduces the computational burden by reducing the number of Fourier transformations...
March 5, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28247879/rapid-and-specific-detection-of-cell-derived-microvesicles-using-a-magnetoresistive-biochip
#10
Solène Cherré, Elisabete Fernandes, José Germano, Tomás Dias, Susana Cardoso, Moisés S Piedade, Noemi Rozlosnik, Marta I Oliveira, Paulo P Freitas
Microvesicles (MVs) are a promising source of diagnostic biomarkers which have gained a wide interest in the biomedical and biosensing field. They can be interpreted as a "fingerprint" of various diseases. Nonetheless, MVs implementation into clinical settings has been hampered by the lack of technologies to accurately characterize, detect and quantify them. Here, we report the specific sensing and quantification of MVs from endothelial cells using a portable magnetoresistive (MR) biochip platform, in less than one hour and within physiologically relevant concentrations (1 × 10(8) MVs per ml)...
March 13, 2017: Analyst
https://www.readbyqxmd.com/read/28238942/algorithm-comparison-for-schedule-optimization-in-mr-fingerprinting
#11
Ouri Cohen, Matthew S Rosen
In MR Fingerprinting, the flip angles and repetition times are chosen according to a pseudorandom schedule. In previous work, we have shown that maximizing the discrimination between different tissue types by optimizing the acquisition schedule allows reductions in the number of measurements required. The ideal optimization algorithm for this application remains unknown, however. In this work we examine several different optimization algorithms to determine the one best suited for optimizing MR Fingerprinting acquisition schedules...
February 24, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28226533/optimal-experiment-design-for-magnetic-resonance-fingerprinting
#12
Bo Zhao, Justin P Haldar, Kawin Setsompop, Lawrence L Wald, Bo Zhao, Justin P Haldar, Kawin Setsompop, Lawrence L Wald, Bo Zhao, Lawrence L Wald, Justin P Haldar, Kawin Setsompop
Magnetic resonance (MR) fingerprinting is an emerging quantitative MR imaging technique that simultaneously acquires multiple tissue parameters in an efficient experiment. In this work, we present an estimation-theoretic framework to evaluate and design MR fingerprinting experiments. More specifically, we derive the Cramér-Rao bound (CRB), a lower bound on the covariance of any unbiased estimator, to characterize parameter estimation for MR fingerprinting. We then formulate an optimal experiment design problem based on the CRB to choose a set of acquisition parameters (e...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28187264/development-of-a-combined-mr-fingerprinting-and-diffusion-examination-for-prostate-cancer
#13
Alice C Yu, Chaitra Badve, Lee E Ponsky, Shivani Pahwa, Sara Dastmalchian, Matthew Rogers, Yun Jiang, Seunghee Margevicius, Mark Schluchter, William Tabayoyong, Robert Abouassaly, Debra McGivney, Mark A Griswold, Vikas Gulani
Purpose To develop and evaluate an examination consisting of magnetic resonance (MR) fingerprinting-based T1, T2, and standard apparent diffusion coefficient (ADC) mapping for multiparametric characterization of prostate disease. Materials and Methods This institutional review board-approved, HIPAA-compliant retrospective study of prospectively collected data included 140 patients suspected of having prostate cancer. T1 and T2 mapping was performed with fast imaging with steady-state precession-based MR fingerprinting with ADC mapping...
June 2017: Radiology
https://www.readbyqxmd.com/read/28043909/magnetic-resonance-fingerprinting-based-on-realistic-vasculature-in-mice
#14
Philippe Pouliot, Louis Gagnon, Tina Lam, Pramod K Avti, Chris Bowen, Michèle Desjardins, Ashok K Kakkar, Eric Thorin, Sava Sakadzic, David A Boas, Frédéric Lesage
Magnetic resonance fingerprinting (MRF) was recently proposed as a novel strategy for MR data acquisition and analysis. A variant of MRF called vascular MRF (vMRF) followed, that extracted maps of three parameters of physiological importance: cerebral oxygen saturation (SatO2), mean vessel radius and cerebral blood volume (CBV). However, this estimation was based on idealized 2-dimensional simulations of vascular networks using random cylinders and the empirical Bloch equations convolved with a diffusion kernel...
April 1, 2017: NeuroImage
https://www.readbyqxmd.com/read/28034994/mr-fingerprinting-of-adult-brain-tumors-initial-experience
#15
C Badve, A Yu, S Dastmalchian, M Rogers, D Ma, Y Jiang, S Margevicius, S Pahwa, Z Lu, M Schluchter, J Sunshine, M Griswold, A Sloan, V Gulani
BACKGROUND AND PURPOSE: MR fingerprinting allows rapid simultaneous quantification of T1 and T2 relaxation times. This study assessed the utility of MR fingerprinting in differentiating common types of adult intra-axial brain tumors. MATERIALS AND METHODS: MR fingerprinting acquisition was performed in 31 patients with untreated intra-axial brain tumors: 17 glioblastomas, 6 World Health Organization grade II lower grade gliomas, and 8 metastases. T1, T2 of the solid tumor, immediate peritumoral white matter, and contralateral white matter were summarized within each ROI...
March 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28019022/use-of-pattern-recognition-for-unaliasing-simultaneously-acquired-slices-in-simultaneous-multislice-mr-fingerprinting
#16
Yun Jiang, Dan Ma, Himanshu Bhat, Huihui Ye, Stephen F Cauley, Lawrence L Wald, Kawin Setsompop, Mark A Griswold
PURPOSE: The purpose of this study is to accelerate an MR fingerprinting (MRF) acquisition by using a simultaneous multislice method. METHODS: A multiband radiofrequency (RF) pulse was designed to excite two slices with different flip angles and phases. The signals of two slices were driven to be as orthogonal as possible. The mixed and undersampled MRF signal was matched to two dictionaries to retrieve T1 and T2 maps of each slice. Quantitative results from the proposed method were validated with the gold-standard spin echo methods in a phantom...
December 26, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28019021/multiparametric-estimation-of-brain-hemodynamics-with-mr-fingerprinting-asl
#17
Pan Su, Deng Mao, Peiying Liu, Yang Li, Marco C Pinho, Babu G Welch, Hanzhang Lu
PURPOSE: Assessment of brain hemodynamics without exogenous contrast agents is of increasing importance in clinical applications. This study aims to develop an MR perfusion technique that can provide noncontrast and multiparametric estimation of hemodynamic markers. METHODS: We devised an arterial spin labeling (ASL) method based on the principle of MR fingerprinting (MRF), referred to as MRF-ASL. By taking advantage of the rich information contained in MRF sequence, up to seven hemodynamic parameters can be estimated concomitantly...
December 26, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28008911/geometrical-vortex-lattice-pinning-and-melting-in-ybacuo-submicron-bridges
#18
G P Papari, A Glatz, F Carillo, D Stornaiuolo, D Massarotti, V Rouco, L Longobardi, F Beltram, V M Vinokur, F Tafuri
Since the discovery of high-temperature superconductors (HTSs), most efforts of researchers have been focused on the fabrication of superconducting devices capable of immobilizing vortices, hence of operating at enhanced temperatures and magnetic fields. Recent findings that geometric restrictions may induce self-arresting hypervortices recovering the dissipation-free state at high fields and temperatures made superconducting strips a mainstream of superconductivity studies. Here we report on the geometrical melting of the vortex lattice in a wide YBCO submicron bridge preceded by magnetoresistance (MR) oscillations fingerprinting the underlying regular vortex structure...
December 23, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27937040/multiparametric-or-practical-quantitative-liver-mri-towards-millisecond-fat-fraction-kilopascal-and-function-era
#19
Emre Unal, Ilkay Sedakat Idilman, Muşturay Karçaaltıncaba
New advances in liver magnetic resonance imaging (MRI) may enable diagnosis of unseen pathologies by conventional techniques. Normal T1 (550-620 ms for 1.5 T and 700-850 ms for 3 T), T2, T2* (>20 ms), T1rho (40-50 ms) mapping, proton density fat fraction (PDFF) (≤5%) and stiffness (2-3kPa) values can enable differentiation of a normal liver from chronic liver and diffuse diseases. Gd-EOB-DTPA can enable assessment of liver function by using postcontrast hepatobiliary phase or T1 reduction rate (normally above 60%)...
February 2017: Expert Review of Gastroenterology & Hepatology
https://www.readbyqxmd.com/read/27883015/mr-vascular-fingerprinting-in-stroke-and-brain-tumors-models
#20
B Lemasson, N Pannetier, N Coquery, Ligia S B Boisserand, Nora Collomb, N Schuff, M Moseley, G Zaharchuk, E L Barbier, T Christen
In this study, we evaluated an MRI fingerprinting approach (MRvF) designed to provide high-resolution parametric maps of the microvascular architecture (i.e., blood volume fraction, vessel diameter) and function (blood oxygenation) simultaneously. The method was tested in rats (n = 115), divided in 3 models: brain tumors (9 L, C6, F98), permanent stroke, and a control group of healthy animals. We showed that fingerprinting can robustly distinguish between healthy and pathological brain tissues with different behaviors in tumor and stroke models...
November 24, 2016: Scientific Reports
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