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https://www.readbyqxmd.com/read/28842384/3d-mr-fingerprinting-with-accelerated-stack-of-spirals-and-hybrid-sliding-window-and-grappa-reconstruction
#1
Congyu Liao, Berkin Bilgic, Mary Kate Manhard, Bo Zhao, Xiaozhi Cao, Jianhui Zhong, Lawrence L Wald, Kawin Setsompop
PURPOSE: Whole-brain high-resolution quantitative imaging is extremely encoding intensive, and its rapid and robust acquisition remains a challenge. Here we present a 3D MR fingerprinting (MRF) acquisition with a hybrid sliding-window (SW) and GRAPPA reconstruction strategy to obtain high-resolution T1, T2 and proton density (PD) maps with whole brain coverage in a clinically feasible timeframe. METHODS: 3D MRF data were acquired using a highly under-sampled stack-of-spirals trajectory with a steady-state precession (FISP) sequence...
August 24, 2017: NeuroImage
https://www.readbyqxmd.com/read/28831794/simultaneous-en-face-imaging-of-multiple-layers-with-multiple-reference-optical-coherence-tomography
#2
Kai Neuhaus, Seán O'Gorman, Paul M McNamara, Sergey Alexandrov, Josh Hogan, Carol Wilson, Martin J Leahy
A technique based on multiple reference optical coherence tomography (MR-OCT) is proposed for simultaneous imaging at multiple depths. The technique has been validated by imaging a reference sample and a fingerprint in-vivo. The principle of scanning multiple selected layers is shown by imaging a partial fingerprint with 200×200×200 voxels of 3×3×0.5  mm size and obtaining an arbitrary amount of layers merely by digital processing. The spacing among the layers can be adjusted arbitrarily, and the SNR roll-off is shown for three different spacings...
August 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28804918/low-rank-approximation-methods-for-mr-fingerprinting-with-large-scale-dictionaries
#3
Mingrui Yang, Dan Ma, Yun Jiang, Jesse Hamilton, Nicole Seiberlich, Mark A Griswold, Debra McGivney
PURPOSE: This work proposes new low rank approximation approaches with significant memory savings for large scale MR fingerprinting (MRF) problems. THEORY AND METHODS: We introduce a compressed MRF with randomized singular value decomposition method to significantly reduce the memory requirement for calculating a low rank approximation of large sized MRF dictionaries. We further relax this requirement by exploiting the structures of MRF dictionaries in the randomized singular value decomposition space and fitting them to low-degree polynomials to generate high resolution MRF parameter maps...
August 13, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28796368/regularly-incremented-phase-encoding-mr-fingerprinting-ripe-mrf-for-enhanced-motion-artifact-suppression-in-preclinical-cartesian-mr-fingerprinting
#4
Christian E Anderson, Charlie Y Wang, Yuning Gu, Rebecca Darrah, Mark A Griswold, Xin Yu, Chris A Flask
PURPOSE: The regularly incremented phase encoding-magnetic resonance fingerprinting (RIPE-MRF) method is introduced to limit the sensitivity of preclinical MRF assessments to pulsatile and respiratory motion artifacts. METHODS: As compared to previously reported standard Cartesian-MRF methods (SC-MRF), the proposed RIPE-MRF method uses a modified Cartesian trajectory that varies the acquired phase-encoding line within each dynamic MRF dataset. Phantoms and mice were scanned without gating or triggering on a 7T preclinical MRI scanner using the RIPE-MRF and SC-MRF methods...
August 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28743861/multimodal-fingerprints-of-resting-state-networks-as-assessed-by-simultaneous-trimodal-mr-pet-eeg-imaging
#5
N J Shah, J Arrubla, R Rajkumar, E Farrher, J Mauler, E Rota Kops, L Tellmann, J Scheins, F Boers, J Dammers, P Sripad, C Lerche, K J Langen, H Herzog, I Neuner
Simultaneous MR-PET-EEG (magnetic resonance imaging - positron emission tomography - electroencephalography), a new tool for the investigation of neuronal networks in the human brain, is presented here for the first time. It enables the assessment of molecular metabolic information with high spatial and temporal resolution in a given brain simultaneously. Here, we characterize the brain's default mode network (DMN) in healthy male subjects using multimodal fingerprinting by quantifying energy metabolism via 2- [(18)F]fluoro-2-desoxy-D-glucose PET (FDG-PET), the inhibition - excitation balance of neuronal activation via magnetic resonance spectroscopy (MRS), its functional connectivity via fMRI and its electrophysiological signature via EEG...
July 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28684268/towards-predicting-the-encoding-capability-of-mr-fingerprinting-sequences
#6
K Sommer, T Amthor, M Doneva, P Koken, J Meineke, P Börnert
Sequence optimization and appropriate sequence selection is still an unmet need in magnetic resonance fingerprinting (MRF). The main challenge in MRF sequence design is the lack of an appropriate measure of the sequence's encoding capability. To find such a measure, three different candidates for judging the encoding capability have been investigated: local and global dot-product-based measures judging dictionary entry similarity as well as a Monte Carlo method that evaluates the noise propagation properties of an MRF sequence...
July 3, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28610928/kinetic-and-biophysical-characterization-of-a-lysosomal-%C3%AE-l-fucosidase-from-the-fresh-water-mussel-lamellidens-corrianus
#7
A Venugopal, C Sudheer Kumar, Nadimpalli Siva Kumar, Musti J Swamy
Kinetic and biophysical studies have been carried out on a lysosomal α-l-fucosidase purified from the fresh water mussel, Lamellidens corrianus. The enzyme migrates as a single band in SDS-PAGE as well as native PAGE corresponding to a Mr of 56kDa. Mass spectrometric analysis yielded a molecular mass of 56175.1Da for the enzyme, and peptide mass fingerprinting studies showed that it shares sequence homology with other fucosidases. Zymogram analysis showed that the α-l-fucosidase hydrolyzed 4-methyl umbelliferyl α-l-fucopyranoside...
November 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28433503/mr-fingerprinting-reconstruction-with-kalman-filter
#8
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
#9
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
#10
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 14, 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
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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