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Canales-Rodríguez EJ, Pizzolato M, Zhou FL, Barakovic M, Thiran JP, Jones DK, Parker GJM, Dyrby TB. Pore size estimation in axon-mimicking microfibers with diffusion-relaxation MRI. Magn Reson Med 2024; 91:2579-2596. [PMID: 38192108 DOI: 10.1002/mrm.29991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/04/2023] [Accepted: 12/12/2023] [Indexed: 01/10/2024]
Abstract
PURPOSE This study aims to evaluate two distinct approaches for fiber radius estimation using diffusion-relaxation MRI data acquired in biomimetic microfiber phantoms that mimic hollow axons. The methods considered are the spherical mean power-law approach and a T2-based pore size estimation technique. THEORY AND METHODS A general diffusion-relaxation theoretical model for the spherical mean signal from water molecules within a distribution of cylinders with varying radii was introduced, encompassing the evaluated models as particular cases. Additionally, a new numerical approach was presented for estimating effective radii (i.e., MRI-visible mean radii) from the ground truth radii distributions, not reliant on previous theoretical approximations and adaptable to various acquisition sequences. The ground truth radii were obtained from scanning electron microscope images. RESULTS Both methods show a linear relationship between effective radii estimated from MRI data and ground-truth radii distributions, although some discrepancies were observed. The spherical mean power-law method overestimated fiber radii. Conversely, the T2-based method exhibited higher sensitivity to smaller fiber radii, but faced limitations in accurately estimating the radius in one particular phantom, possibly because of material-specific relaxation changes. CONCLUSION The study demonstrates the feasibility of both techniques to predict pore sizes of hollow microfibers. The T2-based technique, unlike the spherical mean power-law method, does not demand ultra-high diffusion gradients, but requires calibration with known radius distributions. This research contributes to the ongoing development and evaluation of neuroimaging techniques for fiber radius estimation, highlights the advantages and limitations of both methods, and provides datasets for reproducible research.
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Affiliation(s)
- Erick J Canales-Rodríguez
- Signal Processing Laboratory 5 (LTS5), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Danish Research Centre for Magnetic Resonance (DRCMR), Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Copenhagen, Denmark
| | - Marco Pizzolato
- Danish Research Centre for Magnetic Resonance (DRCMR), Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Copenhagen, Denmark
- Department of Applied Mathematics and Computer Science, Technical University of Denmark (DTU), Kongens Lyngby, Denmark
| | - Feng-Lei Zhou
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London (UCL), London, UK
- MicroPhantoms Limited, Cambridge, UK
| | - Muhamed Barakovic
- Translational Imaging in Neurology (ThINk) Basel, Department of Biomedical Engineering, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Jean-Philippe Thiran
- Signal Processing Laboratory 5 (LTS5), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Radiology Department, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
- Centre d'Imagerie Biomédicale (CIBM), EPFL, Lausanne, Switzerland
| | - Derek K Jones
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, UK
| | - Geoffrey J M Parker
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London (UCL), London, UK
- Department of Neuroinflammation, Queen Square Institute of Neurology, University College London (UCL), London, UK
- Bioxydyn Limited, Manchester, UK
| | - Tim B Dyrby
- Danish Research Centre for Magnetic Resonance (DRCMR), Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Copenhagen, Denmark
- Department of Applied Mathematics and Computer Science, Technical University of Denmark (DTU), Kongens Lyngby, Denmark
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Hu C, Grech‐Sollars M, Statton B, Li Z, Gao F, Williams GR, Parker GJM, Zhou F. Direct jet coaxial electrospinning of axon-mimicking fibers for diffusion tensor imaging. POLYM ADVAN TECHNOL 2023; 34:2573-2584. [PMID: 38505514 PMCID: PMC10946859 DOI: 10.1002/pat.6073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/01/2023] [Accepted: 04/16/2023] [Indexed: 03/21/2024]
Abstract
Hollow polymer microfibers with variable microstructural and hydrophilic properties were proposed as building elements to create axon-mimicking phantoms for validation of diffusion tensor imaging (DTI). The axon-mimicking microfibers were fabricated in a mm-thick 3D anisotropic fiber strip, by direct jet coaxial electrospinning of PCL/polysiloxane-based surfactant (PSi) mixture as shell and polyethylene oxide (PEO) as core. Hydrophilic PCL-PSi fiber strips were first obtained by carefully selecting appropriate solvents for the core and appropriate fiber collector rotating and transverse speeds. The porous cross-section and anisotropic orientation of axon-mimicking fibers were then quantitatively evaluated using two ImageJ plugins-nearest distance (ND) and directionality based on their scanning electron microscopy (SEM) images. Third, axon-mimicking phantom was constructed from PCL-PSi fiber strips with variable porous-section and fiber orientation and tested on a 3T clinical MR scanner. The relationship between DTI measurements (mean diffusivity [MD] and fractional anisotropy [FA]) of phantom samples and their pore size and fiber orientation was investigated. Two key microstructural parameters of axon-mimicking phantoms including normalized pore distance and dispersion of fiber orientation could well interpret the variations in DTI measurements. Two PCL-PSi phantom samples made from different regions of the same fiber strips were found to have similar MD and FA values, indicating that the direct jet coaxial electrospun fiber strips had consistent microstructure. More importantly, the MD and FA values of the developed axon-mimicking phantoms were mostly in the biologically relevant range.
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Affiliation(s)
- Chunyan Hu
- College of Textiles and ClothingQingdao UniversityQingdaoChina
| | - Matthew Grech‐Sollars
- Department of Computer ScienceUniversity College LondonLondonUK
- Lysholm Department of Neuroradiology, National Hospital for Neurology and NeurosurgeryUniversity College London Hospitals NHS Foundation TrustLondonUK
| | - Ben Statton
- Medical Research Council, London Institute of Medical SciencesImperial College LondonLondonUK
| | - Zhanxiong Li
- College of Textile and Clothing EngineeringSoochow UniversitySuzhouChina
| | - Fei Gao
- Department of Radiology, Shandong Provincial Hospital, Cheeloo College of MedicineShandong UniversityJinanChina
| | | | - Geoff J. M. Parker
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonUK
- Bioxydyn LimitedManchesterUK
| | - Feng‐Lei Zhou
- College of Textiles and ClothingQingdao UniversityQingdaoChina
- School of PharmacyUniversity College LondonLondonUK
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonUK
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Elyaderani AK, De Lama-Odría MDC, del Valle LJ, Puiggalí J. Multifunctional Scaffolds Based on Emulsion and Coaxial Electrospinning Incorporation of Hydroxyapatite for Bone Tissue Regeneration. Int J Mol Sci 2022; 23:ijms232315016. [PMID: 36499342 PMCID: PMC9738225 DOI: 10.3390/ijms232315016] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/03/2022] Open
Abstract
Tissue engineering is nowadays a powerful tool to restore damaged tissues and recover their normal functionality. Advantages over other current methods are well established, although a continuous evolution is still necessary to improve the final performance and the range of applications. Trends are nowadays focused on the development of multifunctional scaffolds with hierarchical structures and the capability to render a sustained delivery of bioactive molecules under an appropriate stimulus. Nanocomposites incorporating hydroxyapatite nanoparticles (HAp NPs) have a predominant role in bone tissue regeneration due to their high capacity to enhance osteoinduction, osteoconduction, and osteointegration, as well as their encapsulation efficiency and protection capability of bioactive agents. Selection of appropriated polymeric matrices is fundamental and consequently great efforts have been invested to increase the range of properties of available materials through copolymerization, blending, or combining structures constituted by different materials. Scaffolds can be obtained from different processes that differ in characteristics, such as texture or porosity. Probably, electrospinning has the greater relevance, since the obtained nanofiber membranes have a great similarity with the extracellular matrix and, in addition, they can easily incorporate functional and bioactive compounds. Coaxial and emulsion electrospinning processes appear ideal to generate complex systems able to incorporate highly different agents. The present review is mainly focused on the recent works performed with Hap-loaded scaffolds having at least one structural layer composed of core/shell nanofibers.
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Affiliation(s)
- Amirmajid Kadkhodaie Elyaderani
- Departament d’Enginyeria Química, Universitat Politècnica de Catalunya, Escola d’Enginyeria de Barcelona Est-EEBE, 08019 Barcelona, Spain
| | - María del Carmen De Lama-Odría
- Departament d’Enginyeria Química, Universitat Politècnica de Catalunya, Escola d’Enginyeria de Barcelona Est-EEBE, 08019 Barcelona, Spain
| | - Luis J. del Valle
- Departament d’Enginyeria Química, Universitat Politècnica de Catalunya, Escola d’Enginyeria de Barcelona Est-EEBE, 08019 Barcelona, Spain
- Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, Escola d’Enginyeria de Barcelona Est-EEBE, 08019 Barcelona, Spain
- Correspondence: (L.J.d.V.); (J.P.)
| | - Jordi Puiggalí
- Departament d’Enginyeria Química, Universitat Politècnica de Catalunya, Escola d’Enginyeria de Barcelona Est-EEBE, 08019 Barcelona, Spain
- Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, Escola d’Enginyeria de Barcelona Est-EEBE, 08019 Barcelona, Spain
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, 08028 Barcelona, Spain
- Correspondence: (L.J.d.V.); (J.P.)
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Drobnjak I, Neher P, Poupon C, Sarwar T. Physical and digital phantoms for validating tractography and assessing artifacts. Neuroimage 2021; 245:118704. [PMID: 34748954 DOI: 10.1016/j.neuroimage.2021.118704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 10/01/2021] [Accepted: 11/01/2021] [Indexed: 11/17/2022] Open
Abstract
Fiber tractography is widely used to non-invasively map white-matter bundles in vivo using diffusion-weighted magnetic resonance imaging (dMRI). As it is the case for all scientific methods, proper validation is a key prerequisite for the successful application of fiber tractography, be it in the area of basic neuroscience or in a clinical setting. It is well-known that the indirect estimation of the fiber tracts from the local diffusion signal is highly ambiguous and extremely challenging. Furthermore, the validation of fiber tractography methods is hampered by the lack of a real ground truth, which is caused by the extremely complex brain microstructure that is not directly observable non-invasively and that is the basis of the huge network of long-range fiber connections in the brain that are the actual target of fiber tractography methods. As a substitute for in vivo data with a real ground truth that could be used for validation, a widely and successfully employed approach is the use of synthetic phantoms. In this work, we are providing an overview of the state-of-the-art in the area of physical and digital phantoms, answering the following guiding questions: "What are dMRI phantoms and what are they good for?", "What would the ideal phantom for validation fiber tractography look like?" and "What phantoms, phantom datasets and tools used for their creation are available to the research community?". We will further discuss the limitations and opportunities that come with the use of dMRI phantoms, and what future direction this field of research might take.
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Affiliation(s)
- Ivana Drobnjak
- Center for Medical Image Computing, Department of Computer Science, University College London, UK.
| | - Peter Neher
- Division of Medical Image Computing, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Cyril Poupon
- BAOBAB, NeuroSpin, Commissariat à l'Energie Atomique, Institut des Sciences du Vivant Frédéric Joliot, Gif-sur-Yvette, France
| | - Tabinda Sarwar
- School of Computing Technologies, RMIT University, Australia
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Huang CC, Hsu CCH, Zhou FL, Kusmia S, Drakesmith M, Parker GJM, Lin CP, Jones DK. Validating pore size estimates in a complex microfiber environment on a human MRI system. Magn Reson Med 2021; 86:1514-1530. [PMID: 33960501 PMCID: PMC7613441 DOI: 10.1002/mrm.28810] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/18/2021] [Accepted: 03/26/2021] [Indexed: 12/19/2022]
Abstract
PURPOSE Recent advances in diffusion-weighted MRI provide "restricted diffusion signal fraction" and restricting pore size estimates. Materials based on co-electrospun oriented hollow cylinders have been introduced to provide validation for such methods. This study extends this work, exploring accuracy and repeatability using an extended acquisition on a 300 mT/m gradient human MRI scanner, in substrates closely mimicking tissue, that is, non-circular cross-sections, intra-voxel fiber crossing, intra-voxel distributions of pore-sizes, and smaller pore-sizes overall. METHODS In a single-blind experiment, diffusion-weighted data were collected from a biomimetic phantom on a 3T Connectom system using multiple gradient directions/diffusion times. Repeated scans established short-term and long-term repeatability. The total scan time (54 min) matched similar protocols used in human studies. The number of distinct fiber populations was estimated using spherical deconvolution, and median pore size estimated through the combination of CHARMED and AxCaliber3D framework. Diffusion-based estimates were compared with measurements derived from scanning electron microscopy. RESULTS The phantom contained substrates with different orientations, fiber configurations, and pore size distributions. Irrespective of one or two populations within the voxel, the pore-size estimates (~5 μm) and orientation-estimates showed excellent agreement with the median values of pore-size derived from scanning electron microscope and phantom configuration. Measurement repeatability depended on substrate complexity, with lower values seen in samples containing crossing-fibers. Sample-level repeatability was found to be good. CONCLUSION While no phantom mimics tissue completely, this study takes a step closer to validating diffusion microstructure measurements for use in vivo by demonstrating the ability to quantify microgeometry in relatively complex configurations.
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Affiliation(s)
- Chu-Chung Huang
- Key Laboratory of Brain Functional Genomics (MOE & STCSM), Affiliated Mental Health Center (ECNU), Institute of Cognitive Neuroscience, School of Psychology and Cognitive Science, East China Normal University, Shanghai, China
- Shanghai Changning Mental Health Center, Shanghai, China
| | - Chih-Chin Heather Hsu
- Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Feng-Lei Zhou
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
- School of Pharmacy, University College London, London, United Kingdom
| | - Slawomir Kusmia
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom
- Epilepsy Society MRI Unit, Chalfont St Peter, United Kingdom
| | - Mark Drakesmith
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom
| | - Geoff J. M. Parker
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
- Department of Neuroinflammation, Queen Square Institute of Neurology, University College London, London, United Kingdom
- Bioxydyn Limited, Manchester, United Kingdom
| | - Ching-Po Lin
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Derek K. Jones
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom
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Zhou FL, McHugh DJ, Li Z, Gough JE, Williams GR, Parker GJM. Coaxial electrospun biomimetic copolymer fibres for application in diffusion magnetic resonance imaging. BIOINSPIRATION & BIOMIMETICS 2021; 16:046016. [PMID: 33706299 DOI: 10.1088/1748-3190/abedcf] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
Objective. The use of diffusion magnetic resonance imaging (dMRI) opens the door to characterizing brain microstructure because water diffusion is anisotropic in axonal fibres in brain white matter and is sensitive to tissue microstructural changes. As dMRI becomes more sophisticated and microstructurally informative, it has become increasingly important to use a reference object (usually called an imaging phantom) for validation of dMRI. This study aims to develop axon-mimicking physical phantoms from biocopolymers and assess their feasibility for validating dMRI measurements.Approach. We employed a simple and one-step method-coaxial electrospinning-to prepare axon-mimicking hollow microfibres from polycaprolactone-b-polyethylene glycol (PCL-b-PEG) and poly(D, L-lactide-co-glycolic) acid (PLGA), and used them as building elements to create axon-mimicking phantoms. Electrospinning was firstly conducted using two types of PCL-b-PEG and two types of PLGA with different molecular weights in various solvents, with different polymer concentrations, for determining their spinnability. Polymer/solvent concentration combinations with good fibre spinnability were used as the shell material in the following co-electrospinning process in which the polyethylene oxide polymer was used as the core material. Following the microstructural characterization of both electrospun and co-electrospun fibres using optical and electron microscopy, two prototype phantoms were constructed from co-electrospun anisotropic hollow microfibres after inserting them into water-filled test tubes.Main results. Hollow microfibres that mimic the axon microstructure were successfully prepared from the appropriate core and shell material combinations. dMRI measurements of two phantoms on a 7 tesla (T) pre-clinical scanner revealed that diffusivity and anisotropy measurements are in the range of brain white matter.Significance. This feasibility study showed that co-electrospun PCL-b-PEG and PLGA microfibre-based axon-mimicking phantoms could be used in the validation of dMRI methods which seek to characterize white matter microstructure.
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Affiliation(s)
- Feng-Lei Zhou
- Centre for Medical Image Computing, Department of Computer Science, University College London, London WC1V 6LJ, United Kingdom
- UCL School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Damien J McHugh
- Quantitative Biomedical Imaging Laboratory, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Zhanxiong Li
- College of Textile and Clothing Engineering, Soochow University, Suzhou 215021, People's Republic of China
| | - Julie E Gough
- Department of Materials and Henry Royce Institute, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Gareth R Williams
- UCL School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Geoff J M Parker
- Centre for Medical Image Computing, Department of Computer Science, University College London, London WC1V 6LJ, United Kingdom
- Bioxydyn Limited, Manchester, United Kingdom
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Zhu LF, Zheng Y, Fan J, Yao Y, Ahmad Z, Chang MW. A novel core-shell nanofiber drug delivery system intended for the synergistic treatment of melanoma. Eur J Pharm Sci 2019; 137:105002. [DOI: 10.1016/j.ejps.2019.105002] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/09/2019] [Accepted: 07/10/2019] [Indexed: 12/31/2022]
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Zhou FL, Wu H, McHugh DJ, Wimpenny I, Zhang X, Gough JE, Hubbard Cristinacce PL, Parker GJM. Co-electrospraying of tumour cell mimicking hollow polymeric microspheres for diffusion magnetic resonance imaging. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 101:217-227. [PMID: 31029314 DOI: 10.1016/j.msec.2019.03.062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 03/08/2019] [Accepted: 03/18/2019] [Indexed: 12/31/2022]
Abstract
Diffusion magnetic resonance imaging (dMRI) is considered as a useful tool to study solid tumours. However, the interpretation of dMRI signal and validation of quantitative measurements of is challenging. One way to address these challenges is by using a standard reference material that can mimic tumour cell microstructure. There is a growing interest in using hollow polymeric microspheres, mainly prepared by multiple steps, as mimics of cells in healthy and diseased tissue. The present work reports on tumour cell-mimicking materials composed of hollow microspheres for application as a standard material in dMRI. These microspheres were prepared via one-step co-electrospraying process. The shell material was poly(d,l-lactic-co-glycolic acid) (PLGA) polymers with different molecule weights and/or ratios of glycolic acid-to-lactic, while the core was polyethylene glycol (PEG) or ethylene glycol. The resultant co-electrosprayed products were characterised by optical microscopy, scanning electron microscopy (SEM) and synchrotron X-ray micro-CT. These products were found to have variable structures and morphologies, e.g. from spherical particles with/without surface hole, through beaded fibres to smooth fibres, which mainly depend on PLGA composition and core materials. Only the shell material of PLGA polymer with ester terminated, Mw 50,000-75,000 g mol-1, and lactide:glycolide 85:15 formed hollow microspheres via the co-electrospraying process using the core material of 8 wt% PEG/chloroform as the core. A water-filled test object (or phantom) was designed and constructed from samples of the material generated from co-electrosprayed PLGA microspheres and tested on a 7 T MRI scanner. The preliminary MRI results provide evidence that hollow PLGA microspheres can restrict/hinder water diffusion as cells do in tumour tissue, implying that the phantom may be suitable for use as a quantitative validation and calibration tool for dMRI.
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Affiliation(s)
- Feng-Lei Zhou
- Division of Neuroscience and Experimental Psychology, The University of Manchester, Manchester M13 9PT, United Kingdom; The School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom.
| | - HuiHui Wu
- The School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom; Pan Tianshou Arts and Design Academy, Ningbo University, No.818, Fenghua Road, Ningbo 315200, China
| | - Damien J McHugh
- Division of Neuroscience and Experimental Psychology, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Ian Wimpenny
- Division of Neuroscience and Experimental Psychology, The University of Manchester, Manchester M13 9PT, United Kingdom; The School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Xun Zhang
- Henry Moseley X-ray Imaging Facility, School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Julie E Gough
- The School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Penny L Hubbard Cristinacce
- Division of Neuroscience and Experimental Psychology, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Geoff J M Parker
- Division of Neuroscience and Experimental Psychology, The University of Manchester, Manchester M13 9PT, United Kingdom; Bioxydyn Limited, Rutherford House, Manchester Science Park, Pencroft Way, Manchester M15 6SZ, United Kingdom.
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Zhang C, Ding Q, He H, Peng Y, Li C, Mai J, Li JS, Zhong J, Chang MW. Nanoporous hollow fibers as a phantom material for the validation of diffusion magnetic resonance imaging. J Appl Polym Sci 2019. [DOI: 10.1002/app.47617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Chunchen Zhang
- Key Laboratory for Biomedical Engineering of Education Ministry of China; Zhejiang University; Hangzhou 310027 People's Republic of China
- Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal; Zhejiang University; Hangzhou 310027 People's Republic of China
| | - Qiuping Ding
- Key Laboratory for Biomedical Engineering of Education Ministry of China; Zhejiang University; Hangzhou 310027 People's Republic of China
- Center for Brain Imaging Science and Technology, College of Biomedical Engineering and Instrumental Science; Zhejiang University; Hangzhou 310027 People's Republic of China
| | - Hongjian He
- Key Laboratory for Biomedical Engineering of Education Ministry of China; Zhejiang University; Hangzhou 310027 People's Republic of China
- Center for Brain Imaging Science and Technology, College of Biomedical Engineering and Instrumental Science; Zhejiang University; Hangzhou 310027 People's Republic of China
| | - Yu Peng
- College of Civil Engineering and Architecture; Zhejiang University; Hangzhou 310027 People's Republic of China
| | - Chen Li
- Key Laboratory for Biomedical Engineering of Education Ministry of China; Zhejiang University; Hangzhou 310027 People's Republic of China
- Center for Brain Imaging Science and Technology, College of Biomedical Engineering and Instrumental Science; Zhejiang University; Hangzhou 310027 People's Republic of China
| | - John Mai
- Alfred E. Mann Institute for Biomedical Engineering; University of Southern California; California Los Angeles 90089
| | - Jing-Song Li
- Key Laboratory for Biomedical Engineering of Education Ministry of China; Zhejiang University; Hangzhou 310027 People's Republic of China
| | - Jianhui Zhong
- Key Laboratory for Biomedical Engineering of Education Ministry of China; Zhejiang University; Hangzhou 310027 People's Republic of China
- Center for Brain Imaging Science and Technology, College of Biomedical Engineering and Instrumental Science; Zhejiang University; Hangzhou 310027 People's Republic of China
| | - Ming-Wei Chang
- Key Laboratory for Biomedical Engineering of Education Ministry of China; Zhejiang University; Hangzhou 310027 People's Republic of China
- Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal; Zhejiang University; Hangzhou 310027 People's Republic of China
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Grech-Sollars M, Zhou FL, Waldman AD, Parker GJM, Hubbard Cristinacce PL. Stability and reproducibility of co-electrospun brain-mimicking phantoms for quality assurance of diffusion MRI sequences. Neuroimage 2018; 181:395-402. [PMID: 29936312 DOI: 10.1016/j.neuroimage.2018.06.059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/23/2018] [Accepted: 06/20/2018] [Indexed: 10/28/2022] Open
Abstract
Grey and white matter mimicking phantoms are important for assessing variations in diffusion MR measures at a single time point and over an extended period of time. This work investigates the stability of brain-mimicking microfibre phantoms and reproducibility of their MR derived diffusion parameters. The microfibres were produced by co-electrospinning and characterized by scanning electron microscopy (SEM). Grey matter and white matter phantoms were constructed from random and aligned microfibres, respectively. MR data were acquired from these phantoms over a period of 33 months. SEM images revealed that only small changes in fibre microstructure occurred over 30 months. The coefficient of variation in MR measurements across all time-points was between 1.6% and 3.4% for MD across all phantoms and FA in white matter phantoms. This was within the limits expected for intra-scanner variability, thereby confirming phantom stability over 33 months. These specialised diffusion phantoms may be used in a clinical environment for intra and inter-site quality assurance purposes, and for validation of quantitative diffusion biomarkers.
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Affiliation(s)
- Matthew Grech-Sollars
- Department of Surgery and Cancer, Imperial College London, London, UK; Department of Imaging, Imperial College Healthcare NHS Trust, London, UK.
| | - Feng-Lei Zhou
- Division of Informatics, Imaging and Data Sciences, The University of Manchester, Manchester, UK; The School of Materials, The University of Manchester, Manchester, United Kingdom.
| | - Adam D Waldman
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK; Department of Medicine, Imperial College London, UK
| | - Geoff J M Parker
- Division of Informatics, Imaging and Data Sciences, The University of Manchester, Manchester, UK; Bioxydyn Limited, Manchester, UK
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Yoon J, Yang HS, Lee BS, Yu WR. Recent Progress in Coaxial Electrospinning: New Parameters, Various Structures, and Wide Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1704765. [PMID: 30152180 DOI: 10.1002/adma.201704765] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 06/01/2018] [Indexed: 05/27/2023]
Abstract
Electrospinning, a common method for synthesizing 1D nanostructures, has contributed to developments in the electrical, electrochemical, biomedical, and environmental fields. Recently, a coaxial electrospinning process has been used to fabricate new nanostructures with advanced performance, but intricate and delicate process conditions hinder reproducibility and mass production. Herein, recent progress in new emerging parameters for successful coaxial electrospinning, and the various nanostructures and critical application areas resulting from these activities. Relationships between the new parameters and final product characteristics are described, new possibilities for nanostructures achievable via coaxial electrospinning are identified, and new research directions with a view to future applications are suggested.
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Affiliation(s)
- Jihyun Yoon
- Department of Materials Science and Engineering, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Ho-Sung Yang
- Department of Materials Science and Engineering, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Byoung-Sun Lee
- Department of Nanoengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Woong-Ryeol Yu
- Department of Materials Science and Engineering, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
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12
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Janke HP, Güvener N, Dou W, Tiemessen DM, YantiSetiasti A, Cremers JGO, Borm PJA, Feitz WFJ, Heerschap A, Kiessling F, Oosterwijk E. Labeling of Collagen Type I Templates with a Naturally Derived Contrast Agent for Noninvasive MR Imaging in Soft Tissue Engineering. Adv Healthc Mater 2018; 7:e1800605. [PMID: 30058274 DOI: 10.1002/adhm.201800605] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 06/26/2018] [Indexed: 12/14/2022]
Abstract
In vivo monitoring of tissue-engineered constructs is important to assess their integrity, remodeling, and degradation. However, this is challenging when the contrast with neighboring tissues is low, necessitating labeling with contrast agents (CAs), but current CAs have limitations (i.e., toxicity, negative contrast, label instability, and/or inappropriate size). Therefore, a naturally derived hemin-L-lysine (HL) complex is used as a potential CA to label collagen-based templates for magnetic resonance imaging (MRI). Labeling does not change the basic characteristics of the collagen templates. When hybrid templates composed of collagen type I reinforced with degradable polymers are subcutaneously implanted in mice, longitudinal visualization by MRI is possible with good contrast and in correlation with template remodeling. In contrast, unlabeled collagen templates are hardly detectable and the fate of these templates cannot be monitored by MRI. Interestingly, tissue remodeling and vascularization are enhanced within HL-labeled templates. Thus, HL labeling is presented as a promising universal imaging marker to label tissue-engineered implants for MRI, which additionally seems to accelerate tissue regeneration.
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Affiliation(s)
- Heinz P. Janke
- Department of Urology; Radboud Institute for Molecular Life Sciences; Radboud University Medical Center; Geert Grooteplein 28 6525 GA Nijmegen The Netherlands
| | - Nihan Güvener
- Institute for Experimental Molecular Imaging; Center for Biohybrid Medical Systems Uniklinik RWTH and Helmholtz Institute for Biomedical Engineering; RWTH Aachen University; Forckenbeckstr. 55 52074 Aachen Germany
- Nano4Imaging GmbH; Zentrum für Biomedizintechnik (ZBMT); Pauwelsstrasse 17 52074 Aachen Germany
| | - Weiqiang Dou
- Department of Radiology and Nuclear Medicine; Radboud University Medical Center; PO Box 9101 6500 HB Nijmegen The Netherlands
- GE Healthcare; MR Research China; Beijing 100176 China
| | - Dorien M. Tiemessen
- Department of Urology; Radboud Institute for Molecular Life Sciences; Radboud University Medical Center; Geert Grooteplein 28 6525 GA Nijmegen The Netherlands
| | - Anglita YantiSetiasti
- Department of Urology; Radboud Institute for Molecular Life Sciences; Radboud University Medical Center; Geert Grooteplein 28 6525 GA Nijmegen The Netherlands
- Department of Anatomical Pathology; Faculty of Medicine; University of Padjadjaran; Jalan Professor Eyckman No. 38; Bandung 4016 Indonesia
| | - Jozef G. O. Cremers
- Institute for Experimental Molecular Imaging; Center for Biohybrid Medical Systems Uniklinik RWTH and Helmholtz Institute for Biomedical Engineering; RWTH Aachen University; Forckenbeckstr. 55 52074 Aachen Germany
- Nano4Imaging GmbH; Zentrum für Biomedizintechnik (ZBMT); Pauwelsstrasse 17 52074 Aachen Germany
| | - Paul J. A. Borm
- Nano4Imaging GmbH; Zentrum für Biomedizintechnik (ZBMT); Pauwelsstrasse 17 52074 Aachen Germany
| | - Wout F. J. Feitz
- Department of Urology; Radboud Institute for Molecular Life Sciences; Radboud University Medical Center; Geert Grooteplein 28 6525 GA Nijmegen The Netherlands
- Radboudumc Amalia Children's Hospital; Radboud University Medical Center; Geert Grooteplein 28 6525 GA Nijmegen The Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine; Radboud University Medical Center; PO Box 9101 6500 HB Nijmegen The Netherlands
| | - Fabian Kiessling
- Institute for Experimental Molecular Imaging; Center for Biohybrid Medical Systems Uniklinik RWTH and Helmholtz Institute for Biomedical Engineering; RWTH Aachen University; Forckenbeckstr. 55 52074 Aachen Germany
| | - Egbert Oosterwijk
- Department of Urology; Radboud Institute for Molecular Life Sciences; Radboud University Medical Center; Geert Grooteplein 28 6525 GA Nijmegen The Netherlands
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13
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Zhou FL, Li Z, Gough JE, Hubbard Cristinacce PL, Parker GJ. Axon mimicking hydrophilic hollow polycaprolactone microfibres for diffusion magnetic resonance imaging. MATERIALS & DESIGN 2018; 137:394-403. [PMID: 29307950 PMCID: PMC5727678 DOI: 10.1016/j.matdes.2017.10.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 10/12/2017] [Accepted: 10/14/2017] [Indexed: 06/07/2023]
Abstract
Highly hydrophilic hollow polycaprolactone (PCL) microfibres were developed as building elements to create tissue-mimicking test objects (phantoms) for validation of diffusion magnetic resonance imaging (MRI). These microfibres were fabricated by the co-electrospinning of PCL-polysiloxane-based surfactant (PSi) mixture as shell and polyethylene oxide as core. The addition of PSi had a significant effect on the size of resultant electrospun fibres and the formation of hollow microfibres. The presence of PSi in both co-electrospun PCL microfibre surface and cross-section, revealed by X-ray energy dispersive spectroscopy (EDX), enabled water to wet these fibres completely (i.e., zero contact angle) and remained active for up to 12 months after immersing in water. PCL and PCL-PSi fibres with uniaxial orientation were constructed into water-filled phantoms. MR measurement revealed that water molecules diffuse anisotropically in the PCL-PSi phantom. Co-electrospun hollow PCL-PSi microfibres have desirable hydrophilic properties for the construction of a new generation of tissue-mimicking dMRI phantoms.
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Affiliation(s)
- Feng-Lei Zhou
- Division of Informatics, Imaging and Data Sciences, The University of Manchester, Manchester M13 9PT, United Kingdom
- CRUK and EPSRC Cancer Imaging Centre in Cambridge and Manchester, UK
- The School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Zhanxiong Li
- College of Textile and Clothing Engineering, Soochow University, Suzhou 215000, PR China
| | - Julie E. Gough
- The School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom
| | | | - Geoff J.M. Parker
- Division of Informatics, Imaging and Data Sciences, The University of Manchester, Manchester M13 9PT, United Kingdom
- CRUK and EPSRC Cancer Imaging Centre in Cambridge and Manchester, UK
- Bioxydyn Limited, Rutherford House, Manchester Science Park, Pencroft Way, Manchester M15 6SZ, United Kingdom
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14
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Zhou FL, Chirazi A, Gough JE, Hubbard Cristinacce PL, Parker GJM. Hollow Polycaprolactone Microspheres with/without a Single Surface Hole by Co-Electrospraying. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:13262-13271. [PMID: 28901145 PMCID: PMC5821410 DOI: 10.1021/acs.langmuir.7b01985] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/11/2017] [Indexed: 06/07/2023]
Abstract
We describe the co-electrospraying of hollow microspheres from a polycaprolactone (PCL) shell solution and various core solutions including water, cyclohexane, poly(ethylene oxide) (PEO), and polyethylene glycol (PEG), using different collectors. The morphologies of the resultant microspheres were characterized by scanning electron microscopy (SEM), confocal microscopy, and nano-X-ray computed tomography (nano-XCT). The core/shell solution miscibility played an important role in the co-electrospraying process and the formation of microsphere structures. Spherical particles were more likely to be produced from miscible combinations of core/shell solutions than from immiscible ones. Hollow PCL microspheres with a single hole in their surfaces were produced when an ethanol bath was used as the collector. The mechanism by which the core/shell structure is transformed into single-hole hollow microspheres is proposed to be primarily based on the evaporation through the shell and extraction by ethanol of the core solution and is described in detail. Additionally, we present a 3D macroscopic tubular structure composed of hollow PCL microspheres, directly assembled on a copper wire collector during co-electrospraying. SEM and nano-XCT confirm that microspheres in the 3D bulk structure remain hollow.
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Affiliation(s)
- Feng-Lei Zhou
- Division
of Informatics, Imaging and Data Sciences and School of Psychological Sciences, The University of Manchester, Manchester M13 9PT, United Kingdom
- The School of Materials and Henry Moseley
X-ray Imaging Facility, School
of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom
- CRUK and EPSRC Cancer
Imaging Centre in Cambridge and Manchester, 27 Palatine Road, Manchester M20 3LJ, United Kingdom
| | - Ali Chirazi
- The School of Materials and Henry Moseley
X-ray Imaging Facility, School
of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Julie E. Gough
- The School of Materials and Henry Moseley
X-ray Imaging Facility, School
of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Penny L. Hubbard Cristinacce
- Division
of Informatics, Imaging and Data Sciences and School of Psychological Sciences, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Geoff J. M. Parker
- Division
of Informatics, Imaging and Data Sciences and School of Psychological Sciences, The University of Manchester, Manchester M13 9PT, United Kingdom
- Bioxydyn Limited, Rutherford
House, Manchester Science Park, Pencroft
Way, Manchester M15 6SZ, United Kingdom
- CRUK and EPSRC Cancer
Imaging Centre in Cambridge and Manchester, 27 Palatine Road, Manchester M20 3LJ, United Kingdom
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15
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Guise C, Fernandes MM, Nóbrega JM, Pathak S, Schneider W, Fangueiro R. Hollow Polypropylene Yarns as a Biomimetic Brain Phantom for the Validation of High-Definition Fiber Tractography Imaging. ACS APPLIED MATERIALS & INTERFACES 2016; 8:29960-29967. [PMID: 27723307 DOI: 10.1021/acsami.6b09809] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Current brain imaging methods largely fail to provide detailed information about the location and severity of axonal injuries and do not anticipate recovery of the patients with traumatic brain injury. High-definition fiber tractography appears as a novel imaging modality based on water motion in the brain that allows for direct visualization and quantification of the degree of axons damage, thus predicting the functional deficits due to traumatic axonal injury and loss of cortical projections. This neuroimaging modality still faces major challenges because it lacks a "gold standard" for the technique validation and respective quality control. The present work aims to study the potential of hollow polypropylene yarns to mimic human white matter axons and construct a brain phantom for the calibration and validation of brain diffusion techniques based on magnetic resonance imaging, including high-definition fiber tractography imaging. Hollow multifilament polypropylene yarns were produced by melt-spinning process and characterized in terms of their physicochemical properties. Scanning electronic microscopy images of the filaments cross section has shown an inner diameter of approximately 12 μm, confirming their appropriateness to mimic the brain axons. The chemical purity of polypropylene yarns as well as the interaction between the water and the filament surface, important properties for predicting water behavior and diffusion inside the yarns, were also evaluated. Restricted and hindered water diffusion was confirmed by fluorescence microscopy. Finally, the yarns were magnetic resonance imaging scanned and analyzed using high-definition fiber tractography, revealing an excellent choice of these hollow polypropylene structures for simulation of the white matter brain axons and their suitability for constructing an accurate brain phantom.
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Affiliation(s)
- Catarina Guise
- Centre for Textile Science and Technology (2C2T), University of Minho , Campus de Azurém, 4800-058 Guimarães, Portugal
| | - Margarida M Fernandes
- Centre for Textile Science and Technology (2C2T), University of Minho , Campus de Azurém, 4800-058 Guimarães, Portugal
| | - João M Nóbrega
- Institute for Polymers and Composites/I3N, University of Minho , Campus of Azurém, 4800-058 Guimarães, Portugal
| | - Sudhir Pathak
- Learning Research and Development Center, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Walter Schneider
- Learning Research and Development Center, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Raul Fangueiro
- Centre for Textile Science and Technology (2C2T), University of Minho , Campus de Azurém, 4800-058 Guimarães, Portugal
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16
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Teh I, Zhou FL, Hubbard Cristinacce PL, Parker GJM, Schneider JE. Biomimetic phantom for cardiac diffusion MRI. J Magn Reson Imaging 2016; 43:594-600. [PMID: 26213152 PMCID: PMC4762200 DOI: 10.1002/jmri.25014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 07/06/2015] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Diffusion magnetic resonance imaging (MRI) is increasingly used to characterize cardiac tissue microstructure, necessitating the use of physiologically relevant phantoms for methods development. Existing phantoms are generally simplistic and mostly simulate diffusion in the brain. Thus, there is a need for phantoms mimicking diffusion in cardiac tissue. MATERIALS AND METHODS A biomimetic phantom composed of hollow microfibers generated using co-electrospinning was developed to mimic myocardial diffusion properties and fiber and sheet orientations. Diffusion tensor imaging was carried out at monthly intervals over 4 months at 9.4T. 3D fiber tracking was performed using the phantom and compared with fiber tracking in an ex vivo rat heart. RESULTS The mean apparent diffusion coefficient and fractional anisotropy of the phantom remained stable over the 4-month period, with mean values of 7.53 ± 0.16 × 10(-4) mm(2) /s and 0.388 ± 0.007, respectively. Fiber tracking of the 1st and 3rd eigenvectors generated analogous results to the fiber and sheet-normal direction respectively, found in the left ventricular myocardium. CONCLUSION A biomimetic phantom simulating diffusion in the heart was designed and built. This could aid development and validation of novel diffusion MRI methods for investigating cardiac microstructure, decrease the number of animals and patients needed for methods development, and improve quality control in longitudinal and multicenter cardiac diffusion MRI studies.
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Affiliation(s)
- Irvin Teh
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Feng-Lei Zhou
- Centre for Imaging Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
- The School of Materials, University of Manchester, Manchester, UK
| | - Penny L Hubbard Cristinacce
- Centre for Imaging Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
- Biomedical Imaging Institute, University of Manchester, Manchester, UK
| | - Geoffrey J M Parker
- Centre for Imaging Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
- Biomedical Imaging Institute, University of Manchester, Manchester, UK
| | - Jürgen E Schneider
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
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17
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Zhou FL, Parker GJ, Eichhorn SJ, Hubbard Cristinacce PL. Production and cross-sectional characterization of aligned co-electrospun hollow microfibrous bulk assemblies. MATERIALS CHARACTERIZATION 2015; 109:25-35. [PMID: 26702249 PMCID: PMC4659418 DOI: 10.1016/j.matchar.2015.09.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/13/2015] [Indexed: 05/05/2023]
Abstract
The development of co-electrospun (co-ES) hollow microfibrous assemblies of an appreciable thickness is critical for many practical applications, including filtration membranes and tissue-mimicking scaffolds. In this study, thick uniaxially aligned hollow microfibrous assemblies forming fiber bundles and strips were prepared by co-ES of polycaprolactone (PCL) and polyethylene oxide (PEO) as shell and core materials, respectively. Hollow microfiber bundles were deposited on a fixed rotating disc, which resulted in non-controllable cross-sectional shapes on a macroscopic scale. In comparison, fiber strips were produced with tuneable thickness and width by additionally employing an x-y translation stage in co-ES. Scanning electron microscopy (SEM) images of cross-sections of fiber assemblies were analyzed to investigate the effects of production time (from 0.5 h to 12 h), core flow rate (from 0.8 mL/h to 2.0 mL/h) and/or translation speed (from 0.2 mm/s to 5 mm/s) on the pores and porosity. We observed significant changes in pore size and shape with core flow rate but the influence of production time varied; five strips produced under the same conditions had reasonably good size and porosity reproducibility; pore sizes didn't vary significantly from strip bottom to surface, although the porosity gradually decreased and then returned to the initial level.
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Affiliation(s)
- Feng-Lei Zhou
- Centre for Imaging Sciences, The University of Manchester, Manchester M13 9PT, UK
- The School of Materials, The University of Manchester, Manchester M13 9PL, UK
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester, UK
| | - Geoff J.M. Parker
- Centre for Imaging Sciences, The University of Manchester, Manchester M13 9PT, UK
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester, UK
| | - Stephen J. Eichhorn
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK
| | - Penny L. Hubbard Cristinacce
- Centre for Imaging Sciences, The University of Manchester, Manchester M13 9PT, UK
- School of Psychological Sciences, University of Manchester, Manchester M13 9PT, UK
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18
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Yang T, Zou HY, Huang CZ. Synergetic catalytic effect of Cu2-xSe nanoparticles and reduced graphene oxide coembedded in electrospun nanofibers for the reduction of a typical refractory organic compound. ACS APPLIED MATERIALS & INTERFACES 2015; 7:15447-15457. [PMID: 26114332 DOI: 10.1021/acsami.5b03645] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A new heterogeneous catalytic composite composed of nonstoichiometric Cu2-xSe nanoparticles (NPs) with high copper deficiency and graphene oxide (GO) is prepared by coembedding in electrospun nanofibers of a poly(vinylpyrrolidone) (PVP) support, wherein GO in the nanofibers is converted into reduced GO (rGO) via heat treatment. The as-prepared composite Cu2-xSe/rGO/PVP nanofibers have demonstrated superior catalytic activity toward the reduction of a refractory organic compound by taking 4-nitrophenol (4-NP) as an example. In the presence of NaBH4, the Cu2-xSe/rGO/PVP nanofibers display a synergetic effect between Cu2-xSe and rGO in PVP nanofibers compared to their independent components or corresponding nanofibers. Furthermore, the Cu2-xSe/rGO/PVP nanofibers exhibit a favorable water-stable property via heat treatment to solidify the hydrophilic PVP matrix, which makes the composite display good reusability, stability in aqueous solution, and separability from a water medium. This work not only presents a direct, convenient, and effective approach to doping semiconductor nanomaterials into polymer nanofibers but also provides fundamental routes for further investigations about the synergetic effect between different materials based on the platform of electrospun nanofibers.
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Affiliation(s)
- Tong Yang
- †Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China
| | - Hong Yan Zou
- ‡College of Pharmaceutical Science, Southwest University, Chongqing 400716, P. R. China
| | - Cheng Zhi Huang
- †Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China
- ‡College of Pharmaceutical Science, Southwest University, Chongqing 400716, P. R. China
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19
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Chen G, Fang D, Wang K, Nie J, Ma G. Core-shell structure PEO/CS nanofibers based on electric field induced phase separation via electrospinning and its application. ACTA ACUST UNITED AC 2015. [DOI: 10.1002/pola.27702] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Guangkai Chen
- Beijing Laboratory of Biomedical Materials; State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology; Beijing 100029 People's Republic of China
- School of Materials Science and Engineering, Changzhou University; Changzhou Jiangsu 213164 People's Republic of China
| | - Dawei Fang
- Beijing Laboratory of Biomedical Materials; State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology; Beijing 100029 People's Republic of China
| | - Kemin Wang
- School of Materials Science and Engineering, Changzhou University; Changzhou Jiangsu 213164 People's Republic of China
| | - Jun Nie
- Beijing Laboratory of Biomedical Materials; State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology; Beijing 100029 People's Republic of China
| | - Guiping Ma
- Beijing Laboratory of Biomedical Materials; State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology; Beijing 100029 People's Republic of China
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20
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Grech-Sollars M, Hales PW, Miyazaki K, Raschke F, Rodriguez D, Wilson M, Gill SK, Banks T, Saunders DE, Clayden JD, Gwilliam MN, Barrick TR, Morgan PS, Davies NP, Rossiter J, Auer DP, Grundy R, Leach MO, Howe FA, Peet AC, Clark CA. Multi-centre reproducibility of diffusion MRI parameters for clinical sequences in the brain. NMR IN BIOMEDICINE 2015; 28:468-85. [PMID: 25802212 PMCID: PMC4403968 DOI: 10.1002/nbm.3269] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 01/08/2015] [Accepted: 01/20/2015] [Indexed: 05/06/2023]
Abstract
The purpose of this work was to assess the reproducibility of diffusion imaging, and in particular the apparent diffusion coefficient (ADC), intra-voxel incoherent motion (IVIM) parameters and diffusion tensor imaging (DTI) parameters, across multiple centres using clinically available protocols with limited harmonization between sequences. An ice-water phantom and nine healthy volunteers were scanned across fives centres on eight scanners (four Siemens 1.5T, four Philips 3T). The mean ADC, IVIM parameters (diffusion coefficient D and perfusion fraction f) and DTI parameters (mean diffusivity MD and fractional anisotropy FA), were measured in grey matter, white matter and specific brain sub-regions. A mixed effect model was used to measure the intra- and inter-scanner coefficient of variation (CV) for each of the five parameters. ADC, D, MD and FA had a good intra- and inter-scanner reproducibility in both grey and white matter, with a CV ranging between 1% and 7.4%; mean 2.6%. Other brain regions also showed high levels of reproducibility except for small structures such as the choroid plexus. The IVIM parameter f had a higher intra-scanner CV of 8.4% and inter-scanner CV of 24.8%. No major difference in the inter-scanner CV for ADC, D, MD and FA was observed when analysing the 1.5T and 3T scanners separately. ADC, D, MD and FA all showed good intra-scanner reproducibility, with the inter-scanner reproducibility being comparable or faring slightly worse, suggesting that using data from multiple scanners does not have an adverse effect compared with using data from the same scanner. The IVIM parameter f had a poorer inter-scanner CV when scanners of different field strengths were combined, and the parameter was also affected by the scan acquisition resolution. This study shows that the majority of diffusion MRI derived parameters are robust across 1.5T and 3T scanners and suitable for use in multi-centre clinical studies and trials.
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Affiliation(s)
- Matthew Grech-Sollars
- Developmental Imaging and Biophysics Section, UCL Institute of Child Health, University College LondonLondon, UK
| | - Patrick W Hales
- Developmental Imaging and Biophysics Section, UCL Institute of Child Health, University College LondonLondon, UK
| | - Keiko Miyazaki
- CR UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Foundation TrustBelmont, Surrey, UK
| | - Felix Raschke
- Division of Clinical Sciences, St George's, University of LondonLondon, UK
| | - Daniel Rodriguez
- Division of Clinical Neuroscience, School of Medicine, University of NottinghamNottingham, UK
- The Children‘s Brain Tumour Research Centre, University of NottinghamNottingham, UK
| | - Martin Wilson
- School of Cancer Sciences, University of BirminghamBirmingham, UK
| | - Simrandip K Gill
- School of Cancer Sciences, University of BirminghamBirmingham, UK
| | - Tina Banks
- Department of Radiology, Great Ormond Street Hospital for ChildrenLondon, UK
| | - Dawn E Saunders
- Department of Radiology, Great Ormond Street Hospital for ChildrenLondon, UK
| | - Jonathan D Clayden
- Developmental Imaging and Biophysics Section, UCL Institute of Child Health, University College LondonLondon, UK
| | - Matt N Gwilliam
- CR UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Foundation TrustBelmont, Surrey, UK
| | - Thomas R Barrick
- Division of Clinical Sciences, St George's, University of LondonLondon, UK
| | - Paul S Morgan
- Division of Clinical Neuroscience, School of Medicine, University of NottinghamNottingham, UK
- The Children‘s Brain Tumour Research Centre, University of NottinghamNottingham, UK
| | - Nigel P Davies
- Imaging and Medical Physics, University Hospitals Birmingham NHS Foundation TrustBirmingham, UK
| | - James Rossiter
- Electrical and Computer Engineering, University of BirminghamBirmingham, UK
| | - Dorothee P Auer
- Division of Clinical Neuroscience, School of Medicine, University of NottinghamNottingham, UK
- The Children‘s Brain Tumour Research Centre, University of NottinghamNottingham, UK
| | - Richard Grundy
- The Children‘s Brain Tumour Research Centre, University of NottinghamNottingham, UK
| | - Martin O Leach
- CR UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Foundation TrustBelmont, Surrey, UK
| | - Franklyn A Howe
- Division of Clinical Sciences, St George's, University of LondonLondon, UK
| | - Andrew C Peet
- School of Cancer Sciences, University of BirminghamBirmingham, UK
| | - Chris A Clark
- Developmental Imaging and Biophysics Section, UCL Institute of Child Health, University College LondonLondon, UK
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21
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Zhou XH, Kang WM, Xu W, Cheng BW. Flexible hollow CeO2/Al2O3 fibers: preparation, characterization and dye adsorption efficiency. RSC Adv 2015. [DOI: 10.1039/c5ra14540f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Flexible hollow CeO2/Al2O3 fibers were prepared by a coaxial electro-blowing spinning technique and exhibited strong adsorption capacity for MO molecules.
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Affiliation(s)
- Xing-hai Zhou
- School of Textiles
- Tianjin Polytechnic University
- Tianjin 300387
- China
| | - Wei-min Kang
- School of Textiles
- Tianjin Polytechnic University
- Tianjin 300387
- China
| | - Wei Xu
- School of Textiles
- Tianjin Polytechnic University
- Tianjin 300387
- China
| | - Bo-wen Cheng
- School of Textiles
- Tianjin Polytechnic University
- Tianjin 300387
- China
- Key Laboratory of Advanced Textile Composite Materials
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McHugh DJ, Zhou F, Cristinacce PLH, Naish JH, Parker GJM. Ground Truth for Diffusion MRI in Cancer: A Model-Based Investigation of a Novel Tissue-Mimetic Material. INFORMATION PROCESSING IN MEDICAL IMAGING : PROCEEDINGS OF THE ... CONFERENCE 2015; 24:179-90. [PMID: 26223047 DOI: 10.1007/978-3-319-19992-4_14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
This work presents preliminary results on the development, characterisation, and use of a novel physical phantom designed as a simple mimic of tumour cellular structure, for diffusion-weighted magnetic resonance imaging (DW-MRI) applications. The phantom consists of a collection of roughly spherical, micron-sized core-shell polymer 'cells', providing a system whose ground truth microstructural properties can be determined and compared with those obtained from modelling the DW-MRI signal. A two-compartment analytic model combining restricted diffusion inside a sphere with hindered extracellular diffusion was initially investigated through Monte Carlo diffusion simulations, allowing a comparison between analytic and simulated signals. The model was then fitted to DW-MRI data acquired from the phantom over a range of gradient strengths and diffusion times, yielding estimates of 'cell' size, intracellular volume fraction and the free diffusion coefficient. An initial assessment of the accuracy and precision of these estimates is provided, using independent scanning electron microscope measurements and bootstrap-style simulations. Such phantoms may be useful for testing microstructural models relevant to the characterisation of tumour tissue.
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Hubbard PL, Zhou FL, Eichhorn SJ, Parker GJM. Biomimetic phantom for the validation of diffusion magnetic resonance imaging. Magn Reson Med 2015; 73:299-305. [PMID: 24469863 DOI: 10.1002/mrm.25107] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/29/2013] [Accepted: 12/10/2013] [Indexed: 11/10/2022]
Abstract
PURPOSE A range of advanced diffusion MRI (dMRI) techniques are currently in development which characterize the orientation of white matter fibers using diffusion tensor imaging (DTI). There is a need for a physical phantom with microstructural features of the brain's white matter to help validate these methods. METHODS Hollow, co-electrospun, aligned fibers with a tuneable size distribution have been produced in bulk and with an MR visible solvent infused into the pores. The morphology and size of the phantoms was assessed using scanning electron microscopy (SEM) and compared with DTI results obtained on both a clinical and preclinical scanner. RESULTS By varying inner diameter of the phantom fibers (from SEM: 9.5 μm, 11.9 μm, 13.4 μm) the radial diffusivity and fractional anisotropy, calculated from DTI, vary between 0.38 ± 0.05 × 10(3) and 0.61 ± 0.06 × 10(3) cm s(-1) and between 0.45 ± 0.05 and 0.33 ± 0.04, respectively. CONCLUSION We envisage that these materials will be used for the validation of novel and established methods within the field of diffusion MRI, as well as for routine quality assurance purposes and for establishing scanner performance in multicenter trials.
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Affiliation(s)
- Penny L Hubbard
- Centre for Imaging Sciences, Manchester Academic Health Sciences Centre, The University of Manchester, Manchester, United Kingdom
- Biomedical Imaging Institute, The University of Manchester, Manchester, United Kingdom
| | - Feng-Lei Zhou
- Centre for Imaging Sciences, Manchester Academic Health Sciences Centre, The University of Manchester, Manchester, United Kingdom
- The School of Materials, The University of Manchester, Manchester, United Kingdom
| | - Stephen J Eichhorn
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
| | - Geoffrey J M Parker
- Centre for Imaging Sciences, Manchester Academic Health Sciences Centre, The University of Manchester, Manchester, United Kingdom
- Biomedical Imaging Institute, The University of Manchester, Manchester, United Kingdom
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Daducci A, Canales-Rodríguez EJ, Descoteaux M, Garyfallidis E, Gur Y, Lin YC, Mani M, Merlet S, Paquette M, Ramirez-Manzanares A, Reisert M, Reis Rodrigues P, Sepehrband F, Caruyer E, Choupan J, Deriche R, Jacob M, Menegaz G, Prčkovska V, Rivera M, Wiaux Y, Thiran JP. Quantitative comparison of reconstruction methods for intra-voxel fiber recovery from diffusion MRI. IEEE TRANSACTIONS ON MEDICAL IMAGING 2014; 33:384-399. [PMID: 24132007 DOI: 10.1109/tmi.2013.2285500] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Validation is arguably the bottleneck in the diffusion magnetic resonance imaging (MRI) community. This paper evaluates and compares 20 algorithms for recovering the local intra-voxel fiber structure from diffusion MRI data and is based on the results of the "HARDI reconstruction challenge" organized in the context of the "ISBI 2012" conference. Evaluated methods encompass a mixture of classical techniques well known in the literature such as diffusion tensor, Q-Ball and diffusion spectrum imaging, algorithms inspired by the recent theory of compressed sensing and also brand new approaches proposed for the first time at this contest. To quantitatively compare the methods under controlled conditions, two datasets with known ground-truth were synthetically generated and two main criteria were used to evaluate the quality of the reconstructions in every voxel: correct assessment of the number of fiber populations and angular accuracy in their orientation. This comparative study investigates the behavior of every algorithm with varying experimental conditions and highlights strengths and weaknesses of each approach. This information can be useful not only for enhancing current algorithms and develop the next generation of reconstruction methods, but also to assist physicians in the choice of the most adequate technique for their studies.
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Ye AQ, Hubbard Cristinacce PL, Zhou FL, Yin Z, Parker GJ, Magin RL. Diffusion tensor MRI phantom exhibits anomalous diffusion. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2014; 2014:746-9. [PMID: 25570066 PMCID: PMC4605561 DOI: 10.1109/embc.2014.6943698] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This paper reports diffusion weighted MRI measurements of cyclohexane in a novel diffusion tensor MRI phantom composed of hollow coaxial electrospun fibers (average diameter 10.2 μm). Recent studies of the phantom demonstrated its potential as a calibration standard at low b values (less than 1000 s/mm<;sup>2<;/sup>) for mean diffusivity and fractional anisotropy. In this paper, we extend the characterization of cyclohexane diffusion in this heterogeneous, anisotropic material to high b values (up to 5000 s/mm<;sup>2<;/sup>), where the apparent diffusive motion of the cyclohexane exhibits anomalous behavior (i.e., the molecular mean squared displacement increases with time raised to the fractional power 2α/β). Diffusion tensor MRI was performed at 9.4 T using an Agilent imaging scanner and the data fit to a fractional order Mittag-Leffler (generalized exponential) decay model. Diffusion along the fibers was found to be Gaussian (2α/β=l), while diffusion across the fibers was sub-diffusive (2α/β<;l). Fiber tract reconstruction of the data was consistent with scanning electron micrograph images of the material. These studies suggest that this phantom material may be used to calibrate MR systems in both the normal (Gaussian) and anomalous diffusion regimes.
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Affiliation(s)
- Allen Q. Ye
- University of Illinois at Chicago, Chicago, IL 60607 USA
| | - Penny L. Hubbard Cristinacce
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Feng-Lei Zhou
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Ziying Yin
- University of Illinois at Chicago, Chicago, IL 60607 USA
| | - Geoff J.M. Parker
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester, University of Manchester, Manchester M13 9PT, United Kingdom
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Richardson S, Siow B, Panagiotaki E, Schneider T, Lythgoe MF, Alexander DC. Viable and fixed white matter: diffusion magnetic resonance comparisons and contrasts at physiological temperature. Magn Reson Med 2013; 72:1151-61. [PMID: 24243402 DOI: 10.1002/mrm.25012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/04/2013] [Accepted: 10/04/2013] [Indexed: 12/11/2022]
Abstract
PURPOSE Fixed samples have been used extensively in diffusion MRI (dMRI) studies. However, fixation causes significant structural changes in tissue. The purpose of this study was to evaluate fixed white matter as a surrogate for viable white matter during development and validation of dMRI methods. METHODS dMRI data was acquired from fixed and viable rat optic nerves maintained in identical conditions in a viable isolated tissue (VIT) chamber. The chamber preserves tissue integrity for 10 h at 37°C. Diffusion tensors (DT) and multi-compartment white matter signal models were fitted to the data. RESULTS When comparing VIT and fixed tissue, DT parameters demonstrated that fixation causes significant reductions in axial diffusivity and increases in radial diffusivity. However, both tissues exhibited similar responses to changes in diffusion times and gradient strengths. Multicompartment models demonstrated differences in parameter estimates (e.g., directional diffusivities) that were analogous to differences in DT parameters. Similarities in multi-compartment model rankings suggested that tissue water populations were broadly maintained postfixation. CONCLUSIONS The data demonstrate that fixed tissue, while maintaining the broad water environment of viable tissue, differs significantly in diffusion parameters. Results from dMRI experiments on fixed tissue may correlate with-but will not directly translate into-results from viable tissue.
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Affiliation(s)
- Simon Richardson
- UCL Centre for Advanced Biomedical Imaging, Department of Medicine, University College London, London, UK; Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK
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Fabrication of magnetic nanofibers via surface-initiated RAFT polymerization and coaxial electrospinning. REACT FUNCT POLYM 2013. [DOI: 10.1016/j.reactfunctpolym.2013.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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