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Wang D, Robison RK, Li Z, Pipe JG. High SNR rapid T 1 -weighted MPRAGE using spiral imaging with long readouts and improved deblurring. Magn Reson Med 2023; 89:951-963. [PMID: 36321560 DOI: 10.1002/mrm.29492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/07/2022]
Abstract
PURPOSE The goal of this work is to present the implementation of 3D spiral high-resolution MPRAGE and to demonstrate that SNR and scan efficiency increase with the increment of readout time. THEORY Simplified signal equations for MPRAGE indicate that the T1 contrast can be kept approximately the same by a simple relationship between the flip angle and the TR. Furthermore, if T1 contrast remains the same, image SNR depends on the square root of the product of the total scan time and the readout time. METHODS MPRAGE spiral sequences were implemented with distributed spirals and spiral staircase on 3 Tesla scanners. Brain images of three volunteers were acquired with different readout times. Spiral images were processed with a joint water-fat separation and deblurring algorithm and compared to Cartesian images. Pure noise data sets were also acquired for SNR evaluation. RESULTS Consistent T1 weighting can be achieved with various spiral readout lengths, and between spiral MPRAGE imaging and the traditional Cartesian MPRAGE imaging. Noise performance analysis demonstrates higher SNR efficiency of spiral MPRAGE imaging with matched T1 contrast compared to the Cartesian reference imaging. CONCLUSION Fast, high SNR MPRAGE imaging is feasible with long readout spiral trajectories.
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Affiliation(s)
- Dinghui Wang
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Zhiqiang Li
- Barrow Neurological Institute, Phoenix, Arizona, USA
| | - James G Pipe
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
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Hill LK, Hoang DM, Chiriboga LA, Wisniewski T, Sadowski MJ, Wadghiri YZ. Detection of Cerebrovascular Loss in the Normal Aging C57BL/6 Mouse Brain Using in vivo Contrast-Enhanced Magnetic Resonance Angiography. Front Aging Neurosci 2020; 12:585218. [PMID: 33192479 PMCID: PMC7606987 DOI: 10.3389/fnagi.2020.585218] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/11/2020] [Indexed: 12/28/2022] Open
Abstract
Microvascular rarefaction, or the decrease in vascular density, has been described in the cerebrovasculature of aging humans, rats, and, more recently, mice in the presence and absence of age-dependent diseases. Given the wide use of mice in modeling age-dependent human diseases of the cerebrovasculature, visualization, and quantification of the global murine cerebrovasculature is necessary for establishing the baseline changes that occur with aging. To provide in vivo whole-brain imaging of the cerebrovasculature in aging C57BL/6 mice longitudinally, contrast-enhanced magnetic resonance angiography (CE-MRA) was employed using a house-made gadolinium-bearing micellar blood pool agent. Enhancement in the vascular space permitted quantification of the detectable, or apparent, cerebral blood volume (aCBV), which was analyzed over 2 years of aging and compared to histological analysis of the cerebrovascular density. A significant loss in the aCBV was detected by CE-MRA over the aging period. Histological analysis via vessel-probing immunohistochemistry confirmed a significant loss in the cerebrovascular density over the same 2-year aging period, validating the CE-MRA findings. While these techniques use widely different methods of assessment and spatial resolutions, their comparable findings in detected vascular loss corroborate the growing body of literature describing vascular rarefaction aging. These findings suggest that such age-dependent changes can contribute to cerebrovascular and neurodegenerative diseases, which are modeled using wild-type and transgenic laboratory rodents.
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Affiliation(s)
- Lindsay K. Hill
- Department of Chemical and Biomolecular Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), NYU Grossman School of Medicine, New York, NY, United States
- Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, SUNY Downstate Medical Center, Brooklyn, NY, United States
| | - Dung Minh Hoang
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), NYU Grossman School of Medicine, New York, NY, United States
- Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, United States
| | - Luis A. Chiriboga
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, United States
| | - Thomas Wisniewski
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, United States
- Department of Neurology, NYU Grossman School of Medicine, New York, NY, United States
- Department of Psychiatry, NYU Grossman School of Medicine, New York, NY, United States
| | - Martin J. Sadowski
- Department of Neurology, NYU Grossman School of Medicine, New York, NY, United States
- Department of Psychiatry, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
| | - Youssef Z. Wadghiri
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), NYU Grossman School of Medicine, New York, NY, United States
- Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, United States
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Young IR, Szeverenyi NM, Du J, Bydder GM. Pulse sequences as tissue property filters (TP-filters): a way of understanding the signal, contrast and weighting of magnetic resonance images. Quant Imaging Med Surg 2020; 10:1080-1120. [PMID: 32489930 PMCID: PMC7242304 DOI: 10.21037/qims.2020.04.07] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 03/23/2020] [Indexed: 02/04/2023]
Abstract
This paper describes a quantitative approach to understanding the signal, contrast and weighting of magnetic resonance (MR) images. It uses the concept of pulse sequences as tissue property (TP) filters and models the signal, contrast and weighting of sequences using either a single TP-filter (univariate model) or several TP-filters (the multivariate model). For the spin echo (SE) sequence using the Bloch equations, voxel signal intensity is plotted against the logarithm of the value of the TPs contributing to the sequence signal to produce three TP-filters, an exponential ρm-filter, a low pass T1-filter and a high pass T2-filter. Using the univariate model which considers signal changes in only one of ρm, T1, or T2 at a time, the first partial derivative of signal with respect to the natural logarithm of ρm, T1 or T2 is the sequence weighting for each filter (for small changes in each TP). Absolute contrast is then the sequence weighting multiplied by the fractional change in TP for each filter. For large changes in TPs, the same approach is followed, but using the mean slope of the filter as the sequence weighting. These approaches can also be used for fractional contrast. The univariate TP-filter model provides a mathematical framework for converting conventional qualitative univariate weighting as used in everyday clinical practice into quantitative univariate weighting. Using the multivariate model which considers several TP-filters together, the relative contributions of each TP to overall sequence and image weighting are expressed as sequence and imaging weighting ratios respectively. This is not possible with conventional qualitative weighting which is univariate. The same approaches are used for inversion recovery (IR), pulsed gradient SE, spoiled gradient echo (SGE), balanced steady state free precession, ultrashort echo time and other pulse sequences. Other TPs such as susceptibility, chemical shift and flow can be included with phase along the Y axis of the TP-filter. Contrast agent effects are also included. In the text TP-filters are distinguished from k-space filters, signal filters (S-filters) which are used in imaging processing as well as to describe windowing the signal width and level of images, and spatial filters. The TP-filters approach resolves many of the ambiguities and inconsistencies associated with conventional qualitative weighting and provides a variety of new insights into the signal, contrast and weighting of MR images which are not apparent using qualitative weighting. The TP-filter approach relates the preparation component of pulse sequences to voxel signal, and contrast between two voxels. This is complementary to k-space which relates the acquisition component of pulse sequences to the spatial properties of MR images and their global contrast.
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Affiliation(s)
- Ian R. Young
- Formerly Department of Electrical Engineering, Imperial College of Science, Technology, and Medicine, London, UK
| | | | - Jiang Du
- Department of Radiology, University of California San Diego, San Diego, USA
| | - Graeme M. Bydder
- Department of Radiology, University of California San Diego, San Diego, USA
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Bertrand A, Baron M, Hoang DM, Hill LK, Mendoza SL, Sigurdsson EM, Wadghiri YZ. In Vivo Evaluation of Neuronal Transport in Murine Models of Neurodegeneration Using Manganese-Enhanced MRI. Methods Mol Biol 2018; 1779:527-541. [PMID: 29886555 DOI: 10.1007/978-1-4939-7816-8_33] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Manganese-enhanced MRI (MRI) is a technique that allows for a noninvasive in vivo estimation of neuronal transport. It relies on the physicochemical properties of manganese, which is both a calcium analogue being transported along neurons by active transport, and a paramagnetic compound that can be detected on conventional T1-weighted images. Here, we report a multi-session MEMRI protocol that helps establish time-dependent curves relating to neuronal transport along the olfactory tract over several days. The characterization of these curves via unbiased fitting enables us to infer objectively a set of three parameters (the rate of manganese transport from the maximum slope, the peak intensity, and the time to peak intensity). These parameters, measured previously in wild type mice during normal aging, have served as a baseline to demonstrate their significant sensitivity to pathogenic processes associated with Tau pathology. Importantly, the evaluation of these three parameters and their use as indicators can be extended to monitor any normal and pathogenic processes where neuronal transport is altered. This approach can be applied to characterize and quantify the effect of any neurological disease conditions on neuronal transport in animal models, together with the efficacy of potential therapies.
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Affiliation(s)
- Anne Bertrand
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), Bernard and Irene Schwartz Center for Biomedical Imaging, NYU School of Medicine and NYU Langone Health, New York, NY, USA.,Institut du Cerveau et la Moelle (ICM), AP-HP-Hôpital Pitié-Salpêtrière, Boulevard de l'hôpital, Sorbonne Universités, UPMC Univ. Paris 06, INSERM, CNRS, Paris, France.,INRIA Paris, Aramis Project-Team, Paris, France
| | - Maria Baron
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), Bernard and Irene Schwartz Center for Biomedical Imaging, NYU School of Medicine and NYU Langone Health, New York, NY, USA
| | - Dung M Hoang
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), Bernard and Irene Schwartz Center for Biomedical Imaging, NYU School of Medicine and NYU Langone Health, New York, NY, USA
| | - Lindsay K Hill
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), Bernard and Irene Schwartz Center for Biomedical Imaging, NYU School of Medicine and NYU Langone Health, New York, NY, USA.,Biomedical Engineering, SUNY Downstate Medical Center, Brooklyn, New York, NY, USA
| | - Sebastian L Mendoza
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), Bernard and Irene Schwartz Center for Biomedical Imaging, NYU School of Medicine and NYU Langone Health, New York, NY, USA
| | - Einar M Sigurdsson
- Department of Neuroscience and Physiology, NYU School of Medicine and NYU Langone Health, New York, NY, USA.,Department of Psychiatry, NYU School of Medicine and NYU Langone Health, New York, NY, USA
| | - Youssef Z Wadghiri
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), Bernard and Irene Schwartz Center for Biomedical Imaging, NYU School of Medicine and NYU Langone Health, New York, NY, USA.
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Kanakia S, Toussaint J, Hoang DM, Mullick Chowdhury S, Lee S, Shroyer KR, Moore W, Wadghiri YZ, Sitharaman B. Towards An Advanced Graphene-Based Magnetic Resonance Imaging Contrast Agent: Sub-acute Toxicity and Efficacy Studies in Small Animals. Sci Rep 2015; 5:17182. [PMID: 26625867 PMCID: PMC4667281 DOI: 10.1038/srep17182] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 09/14/2015] [Indexed: 11/08/2022] Open
Abstract
Current clinical Gd(3+)-based T1 magnetic resonance imaging (MRI) contrast agents (CAs) are suboptimal or unsuitable, especially at higher magnetic fields (>1.5 Tesla) for advanced MRI applications such as blood pool, cellular and molecular imaging. Herein, towards the goal of developing a safe and more efficacious high field T1 MRI CA for these applications, we report the sub-acute toxicity and contrast enhancing capabilities of a novel nanoparticle MRI CA comprising of manganese (Mn(2+)) intercalated graphene nanoparticles functionalized with dextran (hereafter, Mangradex) in rodents. Sub-acute toxicology performed on rats intravenously injected with Mangradex at 1, 50 or 100 mg/kg dosages 3 times per week for three weeks indicated that dosages ≤50 mg/kg could serve as potential diagnostic doses. Whole body 7 Tesla MRI performed on mice injected with Mangradex at a potential diagnostic dose (25 mg/kg or 455 nanomoles Mn(2+)/kg; ~2 orders of magnitude lower than the paramagnetic ion concentration in a typical clinical dose) showed persistent (up to at least 2 hours) contrast enhancement in the vascular branches (Mn(2+) concentration in blood at steady state = 300 ppb, per voxel = 45 femtomoles). The results lay the foundations for further development of Mangradex as a vascular and cellular/ molecular MRI probe.
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Affiliation(s)
- Shruti Kanakia
- Department of Biomedical Engineering, Stony Brook University, New York, NY USA
| | - Jimmy Toussaint
- Department of Biomedical Engineering, Stony Brook University, New York, NY USA
| | - Dung Minh Hoang
- Center for Advanced Imaging Innovation and Research (CAIR), New York University School of Medicine, New York, NY USA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY USA
| | | | - Stephen Lee
- Department of Biomedical Engineering, Stony Brook University, New York, NY USA
| | | | - William Moore
- Department of Radiology, Stony Brook University, Stony Brook, NY, USA
| | - Youssef Z. Wadghiri
- Center for Advanced Imaging Innovation and Research (CAIR), New York University School of Medicine, New York, NY USA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY USA
| | - Balaji Sitharaman
- Department of Biomedical Engineering, Stony Brook University, New York, NY USA
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Bertrand A, Khan U, Hoang DM, Novikov DS, Krishnamurthy P, Rajamohamed Sait HB, Little BW, Sigurdsson EM, Wadghiri YZ. Non-invasive, in vivo monitoring of neuronal transport impairment in a mouse model of tauopathy using MEMRI. Neuroimage 2012; 64:693-702. [PMID: 22960250 DOI: 10.1016/j.neuroimage.2012.08.065] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 07/31/2012] [Accepted: 08/24/2012] [Indexed: 12/27/2022] Open
Abstract
The impairment of axonal transport by overexpression or hyperphosphorylation of tau is well documented for in vitro conditions; however, only a few studies on this phenomenon have been conducted in vivo, using invasive procedures, and with contradictory results. Here we used the non-invasive, Manganese-Enhanced Magnetic Resonance Imaging technique (MEMRI), to study for the first time a pure model of tauopathy, the JNPL3 transgenic mouse line, which overexpresses a mutated (P301L) form of the human tau protein. We show progressive impairment in neuronal transport as tauopathy advances. These findings are further supported by a significant correlation between the severity of the impairment in neuronal transport assessed by MEMRI, and the degree of abnormal tau assessed by histology. Unlike conventional techniques that focus on axonal transport measurement, MEMRI can provide a global analysis of neuronal transport, i.e. from dendrites to axons and at the macroscopic scale of fiber tracts. Neuronal transport impairment has been shown to be a key pathogenic process in Alzheimer's disease and numerous other neurodegenerative disorders. Hence, MEMRI provides a promising set of functional biomarkers to be used during preclinical trials to facilitate the selection of new drugs aimed at restoring neuronal transport in neurodegenerative diseases.
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Affiliation(s)
- Anne Bertrand
- The Bernard & Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY 10016, USA
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Dathe H, Helms G. Exact algebraization of the signal equation of spoiled gradient echo MRI. Phys Med Biol 2010; 55:4231-45. [PMID: 20616401 DOI: 10.1088/0031-9155/55/15/003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The Ernst equation for Fourier transform nuclear magnetic resonance (MR) describes the spoiled steady-state signal created by periodic partial excitation. In MR imaging (MRI), it is commonly applied to spoiled gradient-echo acquisition in the steady state, created by a small flip angle alpha at a repetition time TR much shorter than the longitudinal relaxation time T(1). We describe two parameter transformations of alpha and TR/T(1), which render the Ernst equation as a low-order rational function. Computer algebra can be readily applied for analytically solving protocol optimization, as shown for the dual flip angle experiment. These transformations are based on the half-angle tangent substitution and its hyperbolic analogue. They are monotonic and approach identity for small alpha and small TR/T(1) with a third-order error. Thus, the exact algebraization can be readily applied to fast gradient echo MRI to yield a rational approximation in alpha and TR/T(1). This reveals a fundamental relationship between the square of the flip angle and TR/T(1) which characterizes the Ernst angle, constant degree of T(1)-weighting and the influence of the local radio-frequency field.
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Affiliation(s)
- Henning Dathe
- Department of Orthodontics, Biomechanics Group, University Medical Centre, Göttingen, Germany
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Abstract
Weighting is the term most frequently used to describe magnetic resonance pulse sequences and the concept most commonly used to relate image contrast to differences in magnetic resonance tissue properties. It is generally used in a qualitative sense with the single tissue property thought to be most responsible for the contrast used to describe the weighting of the image as a whole. This article describes a quantitative approach for understanding the weighting of sequences and images, using filters and partial derivatives of signal with respect to logarithms of tissue property values. Univariate and multivariate models are described for several pulse sequences including methods for maximizing weighting and calculating both sequence and image weighting ratios. The approach provides insights into difficulties associated with qualitative use of the concept of weighting and a quantitative basis for assessing the signal, contrast, and weighting of commonly used sequences and images.
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