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  1. Article ; Online: Simultaneous multislice EPI prospective motion correction by real-time receiver phase correction and coil sensitivity map interpolation.

    Li, Bo / Li, Ningzhi / Wang, Ze / Balan, Radu / Ernst, Thomas

    Magnetic resonance in medicine

    2023  Volume 90, Issue 5, Page(s) 1932–1948

    Abstract: Purpose: To improve the image reconstruction for prospective motion correction (PMC) of simultaneous multislice (SMS) EPI of the brain, an update of receiver phase and resampling of coil sensitivities are proposed and evaluated.: Methods: A camera- ... ...

    Abstract Purpose: To improve the image reconstruction for prospective motion correction (PMC) of simultaneous multislice (SMS) EPI of the brain, an update of receiver phase and resampling of coil sensitivities are proposed and evaluated.
    Methods: A camera-based system was used to track head motion (3 translations and 3 rotations) and dynamically update the scan position and orientation. We derived the change in receiver phase associated with a shifted field of view (FOV) and applied it in real-time to each k-space line of the EPI readout trains. Second, for the SMS reconstruction, we adapted resampled coil sensitivity profiles reflecting the movement of slices. Single-shot gradient-echo SMS-EPI scans were performed in phantoms and human subjects for validation.
    Results: Brain SMS-EPI scans in the presence of motion with PMC and no phase correction for scan plane shift showed noticeable artifacts. These artifacts were visually and quantitatively attenuated when corrections were enabled. Correcting misaligned coil sensitivity maps improved the temporal SNR (tSNR) of time series by 24% (p = 0.0007) for scans with large movements (up to ˜35 mm and 30°). Correcting the receiver phase improved the tSNR of a scan with minimal head movement by 50% from 50 to 75 for a United Kingdom biobank protocol.
    Conclusion: Reconstruction-induced motion artifacts in single-shot SMS-EPI scans acquired with PMC can be removed by dynamically adjusting the receiver phase of each line across EPI readout trains and updating coil sensitivity profiles during reconstruction. The method may be a valuable tool for SMS-EPI scans in the presence of subject motion.
    MeSH term(s) Humans ; Echo-Planar Imaging/methods ; Image Processing, Computer-Assisted/methods ; Prospective Studies ; Brain/diagnostic imaging ; Head Movements ; Motion ; Artifacts
    Language English
    Publishing date 2023-07-13
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 605774-3
    ISSN 1522-2594 ; 0740-3194
    ISSN (online) 1522-2594
    ISSN 0740-3194
    DOI 10.1002/mrm.29789
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  2. Article ; Online: US regulatory considerations for low field magnetic resonance imaging systems.

    Krainak, Daniel Michael / Zeng, Rongping / Li, Ningzhi / Woods, Terry O'Riska / Delfino, Jana Gut

    Magma (New York, N.Y.)

    2023  Volume 36, Issue 3, Page(s) 347–354

    Abstract: Although there has been a resurgence of interest in low field magnetic resonance imaging (MRI) systems in recent years, low field MRI is not a new concept. FDA has a long history of evaluating the safety and effectiveness of MRI systems encompassing a ... ...

    Abstract Although there has been a resurgence of interest in low field magnetic resonance imaging (MRI) systems in recent years, low field MRI is not a new concept. FDA has a long history of evaluating the safety and effectiveness of MRI systems encompassing a wide range of field strengths. Many systems seeking marketing authorization today include new technological features (such as artificial intelligence), but this does not fundamentally change the regulatory paradigm for MR systems. In this review, we discuss some of the US regulatory considerations for low field magnetic resonance imaging (MRI) systems, including applicability of existing laws and regulations and how the U.S. Food and Drug Administration (FDA) evaluates low field MRI systems for market authorization. We also discuss regulatory considerations in the review of low field MRI systems incorporating novel AI technology. We foresee that MRI systems of all field strengths intended for general diagnostic use will continue to be evaluated for marketing clearance by the metric of substantial equivalence set forth in the premarket notification pathway.
    MeSH term(s) United States ; Artificial Intelligence ; United States Food and Drug Administration ; Magnetic Resonance Imaging
    Language English
    Publishing date 2023-05-16
    Publishing country Germany
    Document type Journal Article ; Review
    ZDB-ID 1160826-2
    ISSN 1352-8661 ; 0968-5243
    ISSN (online) 1352-8661
    ISSN 0968-5243
    DOI 10.1007/s10334-023-01083-1
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  3. Article ; Online: Segmented 3D Echo Planar Acquisition for Rapid Susceptibility-Weighted Imaging: Application to Microhemorrhage Detection in Traumatic Brain Injury.

    Wang, Wen-Tung / Li, Ningzhi / Papageorgiou, Ioannis / Chan, Leighton / Pham, Dzung L / Butman, John A

    Journal of magnetic resonance imaging : JMRI

    2022  Volume 56, Issue 5, Page(s) 1529–1535

    Abstract: Background: Susceptibility-weighted imaging (SWI) provides superior image contrast of cerebral microhemorrhages (CMBs). It is based on a three-dimensional (3D) gradient echo (GRE) sequence with a relatively long imaging time.: Purpose: To evaluate ... ...

    Abstract Background: Susceptibility-weighted imaging (SWI) provides superior image contrast of cerebral microhemorrhages (CMBs). It is based on a three-dimensional (3D) gradient echo (GRE) sequence with a relatively long imaging time.
    Purpose: To evaluate whether an accelerated 3D segmented echo planar imaging SWI is comparable to GRE SWI in detecting CMBs in traumatic brain injury (TBI).
    Study type: Prospective.
    Subjects: Four healthy volunteers and 46 consecutive subjects (38.0 ± 14.4 years, 16 females; 12 mild, 13 moderate, and 7 severe TBI).
    Field strength/sequence: A 3 T scanner/3D gradient echo and 3D segmented echo planar imaging (segEPI).
    Assessment: Brain images were acquired using GRE and segEPI in a single session (imaging time = 9 minutes 47 seconds and 1 minute 30 seconds, respectively). The signal-to-noise ratio (SNR) calculated from healthy volunteer thalamus and centrum semiovale were compared. CMBs were counted by three raters blinded to diagnostic information.
    Statistical tests: A t-test was used to assess SNR difference. Pearson correlation and Wilcoxon signed-rank test were performed using CMB counts. The intermethod agreement was evaluated using Bland-Altman method. Intermethod and interrater reliabilities of image-based diffuse axonal injury (DAI) diagnoses were evaluated using Cohen's kappa and percent agreement. P ≤ 0.05 was considered statistically significant.
    Results: Thalamus SNRs were 16.9 ± 2.2 and 16.5 ± 3 for GRE and segEPI (P = 0.84), respectively. Centrum semiovale SNRs were 25.8 ± 4.6 and 21.1 ± 2.7 (P = 0.13). The correlation coefficient of CMBs was 0.93, and differences were not significant (P = 0.56-0.85). For DAI diagnoses, Cohen's kappa was 0.62-0.84 and percent agreement was 85%-94%.
    Data conclusion: CMB counts on segEPI and GRE were highly correlated, and DAI diagnosis was made equally effectively. segEPI SWI can potentially replace GRE SWI in detecting TBI CMBs, especially when time constraints are critical.
    Evidence level: 1 TECHNICAL EFFICACY: Stage 2.
    MeSH term(s) Brain Injuries, Traumatic/complications ; Brain Injuries, Traumatic/diagnostic imaging ; Diffuse Axonal Injury ; Echo-Planar Imaging/methods ; Female ; Humans ; Magnetic Resonance Imaging/methods ; Prospective Studies
    Language English
    Publishing date 2022-07-19
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Intramural ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 1146614-5
    ISSN 1522-2586 ; 1053-1807
    ISSN (online) 1522-2586
    ISSN 1053-1807
    DOI 10.1002/jmri.28326
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  4. Article: High Field

    Li, Ningzhi / Li, Shizhe / Shen, Jun

    Frontiers in physics

    2017  Volume 5

    Abstract: ... In ... ...

    Abstract In vivo
    Language English
    Publishing date 2017-07-28
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2721033-9
    ISSN 2296-424X
    ISSN 2296-424X
    DOI 10.3389/fphy.2017.00026
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  5. Article: Phase-encoded single-voxel magnetic resonance spectroscopy for suppressing outer volume signals at 7 Tesla.

    Li, Ningzhi / An, Li / Johnson, Christopher / Shen, Jun

    Biomedical spectroscopy and imaging

    2017  Volume 6, Issue 3-4, Page(s) 101–110

    Abstract: Background: Due to imperfect slice profiles, unwanted signals from outside the selected voxel may significantly contaminate metabolite signals acquired using in vivo magnetic resonance spectroscopy (MRS). The use of outer volume suppression may exceed ... ...

    Abstract Background: Due to imperfect slice profiles, unwanted signals from outside the selected voxel may significantly contaminate metabolite signals acquired using in vivo magnetic resonance spectroscopy (MRS). The use of outer volume suppression may exceed the SAR threshold, especially at high field.
    Objective: We propose using phase-encoding gradients after radiofrequency (RF) excitation to spatially encode unwanted signals originating from outside of the selected single voxel.
    Methods: Phase-encoding gradients were added to a standard single voxel point-resolved spectroscopy (PRESS) sequence which selects a 2 × 2 × 2 cm
    Results: Both phantom and in vivo studies showed that spectra from the phase-encoded PRESS sequence were relatively immune from contamination by oil signals and have more accurate quantification results than spectra from standard PRESS spectra of the same voxel.
    Conclusion: The proposed phase-encoded single-voxel PRESS method can significantly suppress outer volume signals that may appear in the spectra of standard PRESS without increasing RF power deposition.
    Language English
    Publishing date 2017-12-27
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2675605-5
    ISSN 2212-8808 ; 2212-8794
    ISSN (online) 2212-8808
    ISSN 2212-8794
    DOI 10.3233/BSI-170168
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  6. Article ; Online: A novel approach to probing in vivo metabolite relaxation: Linear quantification of spatially modulated magnetization.

    Li, Linqing / Li, Ningzhi / An, Li / Shen, Jun

    Magnetic resonance in medicine

    2017  Volume 79, Issue 5, Page(s) 2491–2499

    Abstract: Purpose: Conventional sequences for metabolite transverse relaxation quantification all generally measure signal changes at different echo times (TEs). However, quantification results obtained via these conventional methods can be very different and are ...

    Abstract Purpose: Conventional sequences for metabolite transverse relaxation quantification all generally measure signal changes at different echo times (TEs). However, quantification results obtained via these conventional methods can be very different and are highly dependent on the type of sequence being applied. TE-dependent effects such as diffusion, macromolecule baseline, and J-coupling modulation contribute significantly to these differences. Here, we propose a novel technique-multiple flip angle pulse-driven ratio of longitudinal steady states (MARzss)-for preparing magnetization with T
    Method: Longitudinal steady states at different flip angles were prepared with trains of radio frequency pulses interspersed with field gradients. The resulting spatially modulated longitudinal magnetization was acquired with a PRESS readout module. A new linear equation for quantification of MARzss was derived from Bloch equations.
    Results: By implementing this readout-independent method, T
    Conclusions: The proposed MARzss technique can be used to largely avoid multi-TE associated interference, including diffusion, macromolecules, and J modulation. This MARzss technology, which is uniquely insensitive to readout sequence type and TE, is a promising technique for more accurately probing in vivo metabolite relaxation. Magn Reson Med 79:2491-2499, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
    MeSH term(s) Adult ; Brain/diagnostic imaging ; Brain/metabolism ; Female ; Glutamic Acid/metabolism ; Humans ; Image Processing, Computer-Assisted/methods ; Magnetic Resonance Imaging/methods ; Male ; Phantoms, Imaging ; Signal Processing, Computer-Assisted ; Young Adult
    Chemical Substances Glutamic Acid (3KX376GY7L)
    Language English
    Publishing date 2017-09-23
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 605774-3
    ISSN 1522-2594 ; 0740-3194
    ISSN (online) 1522-2594
    ISSN 0740-3194
    DOI 10.1002/mrm.26941
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  7. Article ; Online: Reconstruction of randomly under-sampled spectra for in vivo

    Li, Ningzhi / Li, Shizhe / Shen, Jun

    Magnetic resonance imaging

    2016  Volume 37, Page(s) 216–221

    Abstract: Purpose: Over the past decade, many techniques have been developed to reduce radiofrequency (RF) power deposition associated with proton decoupling in in vivo Carbon-13 (: Materials and methods: Essentially, proton decoupling is required only during ... ...

    Abstract Purpose: Over the past decade, many techniques have been developed to reduce radiofrequency (RF) power deposition associated with proton decoupling in in vivo Carbon-13 (
    Materials and methods: Essentially, proton decoupling is required only during randomly selected segments of data acquisition. By taking advantage of the sparse spectral pattern of the carboxylic/amide region of in vivo
    Results: Numerical simulations and in vivo experiments at 7Tesla demonstrated that this novel decoupling and data processing strategy can effectively reduce decoupling power deposition by greater than 30%.
    Conclusion: This study proposes and evaluates a novel approach to acquire
    MeSH term(s) Algorithms ; Brain/diagnostic imaging ; Brain/metabolism ; Carbon Isotopes/metabolism ; Humans ; Image Processing, Computer-Assisted/methods ; Magnetic Resonance Spectroscopy/methods ; Protons
    Chemical Substances Carbon Isotopes ; Protons
    Language English
    Publishing date 2016-12-07
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 604885-7
    ISSN 1873-5894 ; 0730-725X
    ISSN (online) 1873-5894
    ISSN 0730-725X
    DOI 10.1016/j.mri.2016.12.005
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  8. Article ; Online: Quantification of in vivo transverse relaxation of glutamate in the frontal cortex of human brain by radio frequency pulse-driven longitudinal steady state.

    Li, Ningzhi / Li, Linqing / Zhang, Yan / Ferraris Araneta, Maria / Johnson, Christopher / Shen, Jun

    PloS one

    2019  Volume 14, Issue 4, Page(s) e0215210

    Abstract: Purpose: The principal excitatory neurotransmitter glutamate plays an important role in many central nervous system disorders. Because glutamate resides predominantly in glutamatergic neurons, its relaxation properties reflect the intracellular ... ...

    Abstract Purpose: The principal excitatory neurotransmitter glutamate plays an important role in many central nervous system disorders. Because glutamate resides predominantly in glutamatergic neurons, its relaxation properties reflect the intracellular environment of glutamatergic neurons. This study developed an improved echo time-independent technique for measuring transverse relaxation time and demonstrated that this radio frequency (RF)-driven longitudinal steady state technique can reliably measure glutamate transverse relaxation in the frontal cortex, where structural and functional abnormalities have been associated with psychiatric symptoms.
    Method: Bloch and Monte Carlo simulations were performed to improve and optimize the RF-driven, longitudinal, steady-state (MARzss) technique to significantly shorten scan time and increase measurement precision. Optimized four-flip angle measurements at 0°,12°, 24°, and 36° with matched repetition time were used in nine human subjects (6F, 3M; 27-49 years old) at 7 Tesla. Longitudinal and transverse relaxation rates for glutamate were measured from a 2 x 2 x 2 cm3 voxel placed in three different brain regions: gray matter-dominated medial prefrontal lobe, white matter-dominated left frontal lobe, and gray matter-dominated occipital lobe.
    Results: Compared to the original MARzss technique, the scan time per voxel for measuring glutamate transverse relaxation was shortened by more than 50%. In the medial frontal, left frontal, and occipital voxels, the glutamate T2 was found to be 117.5±12.9 ms (mean ± standard deviation, n = 9), 107.3±12.1 (n = 9), and 124.4±16.6 ms (n = 8), respectively.
    Conclusions: The improvements described in this study make the MARZSS technique a viable tool for reliably measuring glutamate relaxation from human subjects in a typical clinical setting. It is expected that this improved technique can be applied to characterize the intracellular environment of glutamatergic neurons in a variety of brain disorders.
    MeSH term(s) Adult ; Female ; Frontal Lobe/diagnostic imaging ; Frontal Lobe/metabolism ; Glutamic Acid/metabolism ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Occipital Lobe/diagnostic imaging ; Occipital Lobe/metabolism ; White Matter/diagnostic imaging ; White Matter/metabolism
    Chemical Substances Glutamic Acid (3KX376GY7L)
    Language English
    Publishing date 2019-04-17
    Publishing country United States
    Document type Clinical Trial ; Journal Article ; Research Support, N.I.H., Intramural
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0215210
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  9. Article ; Online: Spectral fitting using basis set modified by measured B0 field distribution.

    Li, Ningzhi / An, Li / Shen, Jun

    NMR in biomedicine

    2015  Volume 28, Issue 12, Page(s) 1707–1715

    Abstract: This study sought to demonstrate and evaluate a novel spectral fitting method to improve quantification accuracy in the presence of large magnetic field distortion, especially with high fields. MRS experiments were performed using a point-resolved ... ...

    Abstract This study sought to demonstrate and evaluate a novel spectral fitting method to improve quantification accuracy in the presence of large magnetic field distortion, especially with high fields. MRS experiments were performed using a point-resolved spectroscopy (PRESS)-type sequence at 7 T. A double-echo gradient echo (GRE) sequence was used to acquire B0 maps following MRS experiments. The basis set was modified based on the measured B0 distribution within the MRS voxel. Quantification results were obtained after fitting the measured MRS data using the modified basis set. The proposed method was validated using numerical Monte Carlo simulations, phantom measurements, and comparison of occipital lobe MRS measurements under homogeneous and inhomogeneous magnetic field conditions. In vivo results acquired from voxels placed in thalamus and prefrontal cortex regions close to the frontal sinus agreed well with published values. Instead of noise-amplifying complex division, the proposed method treats field variations as part of the signal model, thereby avoiding inherent statistical bias associated with regularization. Simulations and experiments showed that the proposed approach reliably quantified results in the presence of relatively large magnetic field distortion. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
    MeSH term(s) Adult ; Algorithms ; Artifacts ; Brain/anatomy & histology ; Brain/metabolism ; Female ; Humans ; Magnetic Fields ; Magnetic Resonance Imaging/methods ; Magnetic Resonance Spectroscopy/methods ; Male ; Pattern Recognition, Automated/methods ; Reproducibility of Results ; Sensitivity and Specificity ; Young Adult
    Language English
    Publishing date 2015-10-27
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Intramural
    ZDB-ID 1000976-0
    ISSN 1099-1492 ; 0952-3480
    ISSN (online) 1099-1492
    ISSN 0952-3480
    DOI 10.1002/nbm.3430
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  10. Article ; Online: Differential Transcriptomic Signatures of Small Airway Cell Cultures Derived from IPF and COVID-19-Induced Exacerbation of Interstitial Lung Disease.

    Uhl, Katie / Paithankar, Shreya / Leshchiner, Dmitry / Jager, Tara E / Abdelgied, Mohamed / Dixit, Bhavna / Marashdeh, Raya / Luo-Li, Dewen / Tripp, Kaylie / Peraino, Angela M / Tamae Kakazu, Maximiliano / Lawson, Cameron / Chesla, Dave W / Luo-Li, Ningzhi / Murphy, Edward T / Prokop, Jeremy / Chen, Bin / Girgis, Reda E / Li, Xiaopeng

    Cells

    2023  Volume 12, Issue 20

    Abstract: Idiopathic pulmonary fibrosis (IPF) is a pathological condition wherein lung injury precipitates the deposition of scar tissue, ultimately leading to a decline in pulmonary function. Existing research indicates a notable exacerbation in the clinical ... ...

    Abstract Idiopathic pulmonary fibrosis (IPF) is a pathological condition wherein lung injury precipitates the deposition of scar tissue, ultimately leading to a decline in pulmonary function. Existing research indicates a notable exacerbation in the clinical prognosis of IPF patients following infection with COVID-19. This investigation employed bulk RNA-sequencing methodologies to describe the transcriptomic profiles of small airway cell cultures derived from IPF and post-COVID fibrosis patients. Differential gene expression analysis unveiled heightened activation of pathways associated with microtubule assembly and interferon signaling in IPF cell cultures. Conversely, post-COVID fibrosis cell cultures exhibited distinctive characteristics, including the upregulation of pathways linked to extracellular matrix remodeling, immune system response, and TGF-β1 signaling. Notably, BMP signaling levels were elevated in cell cultures derived from IPF patients compared to non-IPF control and post-COVID fibrosis samples. These findings underscore the molecular distinctions between IPF and post-COVID fibrosis, particularly in the context of signaling pathways associated with each condition. A better understanding of the underlying molecular mechanisms holds the promise of identifying potential therapeutic targets for future interventions in these diseases.
    MeSH term(s) Humans ; Transcriptome/genetics ; COVID-19/genetics ; Idiopathic Pulmonary Fibrosis/pathology ; Lung Diseases, Interstitial ; Gene Expression Profiling ; Cell Culture Techniques ; Fibrosis
    Language English
    Publishing date 2023-10-21
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 2661518-6
    ISSN 2073-4409 ; 2073-4409
    ISSN (online) 2073-4409
    ISSN 2073-4409
    DOI 10.3390/cells12202501
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