LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 27

Search options

  1. Book ; Online: Accelerated Parallel Magnetic Resonance Imaging with Compressed Sensing using Structured Sparsity

    Dwork, Nicholas / Englund, Erin K.

    2023  

    Abstract: Compressed sensing is an imaging paradigm that allows one to invert an underdetermined linear system by imposing the a priori knowledge that the sought after solution is sparse (i.e., mostly zeros). Previous works have shown that if one also knows ... ...

    Abstract Compressed sensing is an imaging paradigm that allows one to invert an underdetermined linear system by imposing the a priori knowledge that the sought after solution is sparse (i.e., mostly zeros). Previous works have shown that if one also knows something about the sparsity pattern (the locations where non-zero entries exist), one can take advantage of this structure to improve the quality of the result. A significant application of compressed sensing is magnetic resonance imaging (MRI), where samples are acquired in the Fourier domain. Compressed sensing allows one to reconstruct a high-quality image with fewer samples which can be collected with a faster scan. This increases the robustness of MRI to patient motion since less motion is possible during the shorter scan. Parallel imaging, where multiple coils are used to gather data, is another an more ubiquitously used method for accelerating MRI. Existing combinations of these acceleration methods, such as Sparse SENSE, yield high quality images with an even shorter scan time than either technique alone. In this work, we show how to modify Sparse SENSE with structured sparsity to reconstruct a high quality image with even fewer samples.

    Comment: 8 pages, 5 figures
    Keywords Electrical Engineering and Systems Science - Image and Video Processing
    Publishing date 2023-12-03
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  2. Book ; Online: The Dependence of Parallel Imaging with Linear Predictability on the Undersampling Direction

    McManus, Alex / Becker, Stephen / Dwork, Nicholas

    2023  

    Abstract: Parallel imaging with linear predictability takes advantage of information present in multiple receive coils to accurately reconstruct the image with fewer samples. Commonly used algorithms based on linear predictability include GRAPPA and SPIRiT. We ... ...

    Abstract Parallel imaging with linear predictability takes advantage of information present in multiple receive coils to accurately reconstruct the image with fewer samples. Commonly used algorithms based on linear predictability include GRAPPA and SPIRiT. We present a sufficient condition for reconstruction based on the direction of undersampling and the arrangement of the sensing coils. This condition is justified theoretically and examples are shown using real data. We also propose a metric based on the fully-sampled auto-calibration region which can show which direction(s) of undersampling will allow for a good quality image reconstruction.
    Keywords Electrical Engineering and Systems Science - Image and Video Processing
    Publishing date 2023-01-17
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  3. Book ; Online: Utilizing the Structure of the Curvelet Transform with Compressed Sensing

    Dwork, Nicholas / Larson, Peder E. Z.

    2021  

    Abstract: The discrete curvelet transform decomposes an image into a set of fundamental components that are distinguished by direction and size as well as a low-frequency representation. The curvelet representation is approximately sparse; thus, it is a useful ... ...

    Abstract The discrete curvelet transform decomposes an image into a set of fundamental components that are distinguished by direction and size as well as a low-frequency representation. The curvelet representation is approximately sparse; thus, it is a useful sparsifying transformation to be used with compressed sensing. However, the low-frequency portion is seldom sparse. This manuscript presents a method to modify the redundant sparsifying transformation comprised of the wavelet and curvelet transforms to take advantage of this fact with compressed sensing image reconstruction. Instead of relying on sparsity for this low-frequency estimate, the Nyquist-Shannon theorem specifies a square region centered on the $0$ frequency to be collected, which is used to generate a blurry estimate. A Basis Pursuit Denoising problem is solved to determine the missing details after modifying the sparsifying transformation to take advantage of the known fully sampled region. Improvements in quality are shown on magnetic resonance and optical images.
    Keywords Electrical Engineering and Systems Science - Image and Video Processing
    Publishing date 2021-07-24
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  4. Article ; Online: Optimization in the space domain for density compensation with the nonuniform FFT.

    Dwork, Nicholas / O'Connor, Daniel / Johnson, Ethan M I / Baron, Corey A / Gordon, Jeremy W / Pauly, John M / Larson, Peder E Z

    Magnetic resonance imaging

    2023  Volume 100, Page(s) 102–111

    Abstract: The non-uniform Discrete Fourier Transform algorithm has shown great utility for reconstructing images from non-uniformly spaced Fourier samples in several imaging modalities. Due to the non-uniform spacing, some correction for the variable density of ... ...

    Abstract The non-uniform Discrete Fourier Transform algorithm has shown great utility for reconstructing images from non-uniformly spaced Fourier samples in several imaging modalities. Due to the non-uniform spacing, some correction for the variable density of the samples must be made. Common methods for generating density compensation values are either sub-optimal or only consider a finite set of points in the optimization. This manuscript presents an algorithm for generating density compensation values from a set of Fourier samples that takes into account the point spread function over an entire rectangular region in the image domain. We show that the reconstructed images using the density compensation values of this method are of superior quality when compared to other standard methods. Results are shown with a numerical phantom and with magnetic resonance images of the abdomen and the knee.
    MeSH term(s) Image Processing, Computer-Assisted/methods ; Algorithms ; Abdomen ; Magnetic Resonance Imaging/methods ; Fourier Analysis ; Phantoms, Imaging
    Language English
    Publishing date 2023-03-17
    Publishing country Netherlands
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 604885-7
    ISSN 1873-5894 ; 0730-725X
    ISSN (online) 1873-5894
    ISSN 0730-725X
    DOI 10.1016/j.mri.2023.03.003
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: Quantification of the in vivo brain ultrashort-T

    Deveshwar, Nikhil / Yao, Jingwen / Han, Misung / Dwork, Nicholas / Shen, Xin / Ljungberg, Emil / Caverzasi, Eduardo / Cao, Peng / Henry, Roland / Green, Ari / Larson, Peder E Z

    Magnetic resonance in medicine

    2024  Volume 91, Issue 6, Page(s) 2417–2430

    Abstract: Purpose: Recent work has shown MRI is able to measure and quantify signals of phospholipid membrane-bound protons associated with myelin in the human brain. This work seeks to develop an improved technique for characterizing this brain ultrashort- : ... ...

    Abstract Purpose: Recent work has shown MRI is able to measure and quantify signals of phospholipid membrane-bound protons associated with myelin in the human brain. This work seeks to develop an improved technique for characterizing this brain ultrashort-
    Methods: Data from ultrashort echo time scans from 16 healthy volunteers with variable flip angles (VFA) were collected and fitted into an advanced regression model to quantify signal fraction, relaxation time, and frequency shift of the ultrashort-
    Results: The fitted components show intra-subject differences of different white matter structures and significantly elevated ultrashort-
    Conclusion: The significantly different measured components and measured
    MeSH term(s) Humans ; Healthy Volunteers ; Protons ; Phantoms, Imaging ; Brain/diagnostic imaging ; Magnetic Resonance Imaging/methods ; Phospholipids
    Chemical Substances Protons ; Phospholipids
    Language English
    Publishing date 2024-01-30
    Publishing country United States
    Document type Journal Article
    ZDB-ID 605774-3
    ISSN 1522-2594 ; 0740-3194
    ISSN (online) 1522-2594
    ISSN 0740-3194
    DOI 10.1002/mrm.30013
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article: Probing Human Heart TCA Cycle Metabolism and Response to Glucose Load using Hyperpolarized [2-

    Chen, Hsin-Yu / Gordon, Jeremy W / Dwork, Nicholas / Chung, Brian T / Riselli, Andrew / Sivalokanathan, Sanjay / Bok, Robert A / Slater, James B / Vigneron, Daniel B / Abraham, M Roselle / Larson, Peder E Z

    medRxiv : the preprint server for health sciences

    2023  

    Abstract: Introduction: The normal heart has remarkable metabolic flexibility that permits rapid switching between mitochondrial glucose oxidation and fatty acid (FA) oxidation to generate ATP. Loss of metabolic flexibility has been implicated in the genesis of ... ...

    Abstract Introduction: The normal heart has remarkable metabolic flexibility that permits rapid switching between mitochondrial glucose oxidation and fatty acid (FA) oxidation to generate ATP. Loss of metabolic flexibility has been implicated in the genesis of contractile dysfunction seen in cardiomyopathy. Metabolic flexibility has been imaged in experimental models, using hyperpolarized (HP) [2-
    Methods: Good Manufacturing Practice [2-
    Results: The study protocol which included HP substrate injection, MR scanning and oral glucose load, was performed safely without adverse events. Key downstream metabolites of [2-
    Conclusions: HP [2-
    Language English
    Publishing date 2023-10-19
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.10.16.23297053
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article ; Online: Regional quantification of cardiac metabolism with hyperpolarized [1-

    Larson, Peder E Z / Tang, Shuyu / Liu, Xiaoxi / Sinha, Avantika / Dwork, Nicholas / Sivalokanathan, Sanjay / Liu, Jing / Bok, Robert / Ordovas, Karen G / Slater, James / Gordon, Jeremy W / Abraham, M Roselle

    Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance

    2023  Volume 25, Issue 1, Page(s) 77

    Abstract: Background: The heart has metabolic flexibility, which is influenced by fed/fasting states, and pathologies such as myocardial ischemia and hypertrophic cardiomyopathy (HCM). Hyperpolarized (HP) : Methods: We developed and applied methods for whole- ... ...

    Abstract Background: The heart has metabolic flexibility, which is influenced by fed/fasting states, and pathologies such as myocardial ischemia and hypertrophic cardiomyopathy (HCM). Hyperpolarized (HP)
    Methods: We developed and applied methods for whole-heart imaging of
    Results: We demonstrate whole heart coverage for dynamic measurement of pyruvate-to-lactate conversion via LDH and pyruvate-to-bicarbonate conversion via PDH at a resolution of 6 × 6 × 21 mm
    Conclusions: We demonstrate first-in-human regional quantifications of cardiac metabolism by HP
    MeSH term(s) Humans ; Pyruvic Acid ; Bicarbonates ; Predictive Value of Tests ; Magnetic Resonance Imaging/methods ; Glucose ; Lactic Acid/metabolism ; Carbon Isotopes
    Chemical Substances Pyruvic Acid (8558G7RUTR) ; Bicarbonates ; Glucose (IY9XDZ35W2) ; Lactic Acid (33X04XA5AT) ; Carbon Isotopes
    Language English
    Publishing date 2023-12-14
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 1458034-2
    ISSN 1532-429X ; 1097-6647
    ISSN (online) 1532-429X
    ISSN 1097-6647
    DOI 10.1186/s12968-023-00972-7
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Article ; Online: Fast Imaging for Hyperpolarized MR Metabolic Imaging.

    Gordon, Jeremy W / Chen, Hsin-Yu / Dwork, Nicholas / Tang, Shuyu / Larson, Peder E Z

    Journal of magnetic resonance imaging : JMRI

    2020  Volume 53, Issue 3, Page(s) 686–702

    Abstract: MRI with hyperpolarized carbon-13 agents has created a new type of noninvasive, in vivo metabolic imaging that can be applied in cell, animal, and human studies. The use ... ...

    Abstract MRI with hyperpolarized carbon-13 agents has created a new type of noninvasive, in vivo metabolic imaging that can be applied in cell, animal, and human studies. The use of
    MeSH term(s) Algorithms ; Animals ; Carbon Isotopes ; Humans ; Magnetic Resonance Imaging ; Pyruvic Acid ; Reproducibility of Results ; Signal-To-Noise Ratio
    Chemical Substances Carbon Isotopes ; Pyruvic Acid (8558G7RUTR)
    Language English
    Publishing date 2020-02-10
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 1146614-5
    ISSN 1522-2586 ; 1053-1807
    ISSN (online) 1522-2586
    ISSN 1053-1807
    DOI 10.1002/jmri.27070
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article ; Online: Probing human heart TCA cycle metabolism and response to glucose load using hyperpolarized [2-

    Chen, Hsin-Yu / Gordon, Jeremy W / Dwork, Nicholas / Chung, Brian T / Riselli, Andrew / Sivalokanathan, Sanjay / Bok, Robert A / Slater, James B / Vigneron, Daniel B / Abraham, M Roselle / Larson, Peder E Z

    NMR in biomedicine

    2023  Volume 37, Issue 3, Page(s) e5074

    Abstract: Introduction: The healthy heart has remarkable metabolic flexibility that permits rapid switching between mitochondrial glucose oxidation and fatty acid oxidation to generate ATP. Loss of metabolic flexibility has been implicated in the genesis of ... ...

    Abstract Introduction: The healthy heart has remarkable metabolic flexibility that permits rapid switching between mitochondrial glucose oxidation and fatty acid oxidation to generate ATP. Loss of metabolic flexibility has been implicated in the genesis of contractile dysfunction seen in cardiomyopathy. Metabolic flexibility has been imaged in experimental models, using hyperpolarized (HP) [2-
    Methods: Good manufacturing practice [2-
    Results: The study protocol, which included HP substrate injection, MR scanning, and oral glucose load, was performed safely without adverse events. Key downstream metabolites of [2-
    Conclusions: HP [2-
    MeSH term(s) Humans ; Pyruvic Acid/metabolism ; Myocardium/metabolism ; Glucose/metabolism ; Acetylcarnitine/metabolism ; Myocytes, Cardiac ; Glutamic Acid/metabolism ; Lactates/metabolism ; Carbon Isotopes/metabolism
    Chemical Substances Pyruvic Acid (8558G7RUTR) ; Glucose (IY9XDZ35W2) ; Acetylcarnitine (6DH1W9VH8Q) ; Glutamic Acid (3KX376GY7L) ; Lactates ; Carbon Isotopes
    Language English
    Publishing date 2023-12-06
    Publishing country England
    Document type Journal Article
    ZDB-ID 1000976-0
    ISSN 1099-1492 ; 0952-3480
    ISSN (online) 1099-1492
    ISSN 0952-3480
    DOI 10.1002/nbm.5074
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article: Regional quantification of cardiac metabolism with hyperpolarized [1-

    Larson, Peder E Z / Tang, Shuyu / Liu, Xiaoxi / Sinha, Avantika / Dwork, Nicholas / Sivalokanathan, Sanjay / Liu, Jing / Bok, Robert / Ordovas, Karen G / Slater, James / Gordon, Jeremy W / Abraham, M Roselle

    medRxiv : the preprint server for health sciences

    2023  

    Abstract: Background: The heart has metabolic flexibility, which is influenced by fed/fasting states, and pathologies such as myocardial ischemia and hypertrophic cardiomyopathy (HCM). Hyperpolarized (HP) : Methods: We developed and applied methods for whole- ... ...

    Abstract Background: The heart has metabolic flexibility, which is influenced by fed/fasting states, and pathologies such as myocardial ischemia and hypertrophic cardiomyopathy (HCM). Hyperpolarized (HP)
    Methods: We developed and applied methods for whole-heart imaging of
    Results: We demonstrate whole heart coverage for dynamic measurement of pyruvate-to-lactate conversion via LDH and pyruvate-to-bicarbonate conversion via PDH at a resolution of 6×6×21 mm
    Conclusions: We demonstrate first-in-human regional quantifications of cardiac metabolism by HP
    Language English
    Publishing date 2023-10-19
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.10.16.23297052
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top