Biomimetic phantom for cardiac diffusion MRI

Teh, Irvin; Zhou, Fan; Cristinacce, Penny L. Hubbard; Parker, Gjm; Schneider, Jürgen

doi:10.1002/jmri.25197

Cited by 4 publications

(3 citation statements)

References 16 publications

(17 reference statements)

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“…The inhomogeneous structure in the PLGA fibre phantom can result in the partial volume effects where both fibres and free water contribute to the signal in voxels at the interface, and thus affect dMRI measurements. This is consistent with previous observations, where decreased values of FA were observed in partial voluming of free water [39] or free cyclohexane [40] filled fibre phantoms. The partial volume could contribute to the relatively wider distributions of MD and FA values of the PLGA fibre phantom.…”

Section: Mr Imaging Of Water-filled Pcl-b-peg and Plga Fibre Phantomssupporting

confidence: 94%

Coaxial electrospun biomimetic copolymer fibres for application in diffusion magnetic resonance imaging

Zhou¹,

McHugh²,

Li³

et al. 2021

Bioinspir. Biomim.

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Objective. The use of diffusion magnetic resonance imaging (dMRI) opens the door to characterise 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 imaging phantom) for validation of dMRI. This study aims to develop axon-mimicking physical phantoms from biocopolymers and assess their feasibility to validate 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-lactideco-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. The 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 (PEO) polymer was used as the core material. Following microstructural characterisation 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 waterfilled 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 microfibres-based axon-mimicking phantoms could be used in the validation of dMRI methods which seek to characterise white matter microstructure.

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Section: Mr Imaging Of Water-filled Pcl-b-peg and Plga Fibre Phantomssupporting

confidence: 94%

Coaxial electrospun biomimetic copolymer fibres for application in diffusion magnetic resonance imaging

Zhou¹,

McHugh²,

Li³

et al. 2021

Bioinspir. Biomim.

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“…Despite these limitations, this study can be considered as a useful step in the evolution of validating pore size estimates in complex geometries on a human MRI scanner. Similar validations in non‐uniform pore phantoms in relatively short scanning times will enlighten the clinical practice of microstructural imaging in different living tissues including, but not limited to, the prostate, 55 and muscle fibers 56,57 …”

Section: Discussionmentioning

confidence: 76%

Validating pore size estimates in a complex microfiber environment on a human MRI system

Huang

Hsu

Zhou

et al. 2021

Magnetic Resonance in Med

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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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“…Despite these limitations, this study can be considered as a useful step in the evolution of validating pore size estimates in complex geometries on a human MRI scanner. Similar validations in non-uniform pore phantoms in relatively short scanning times will enlighten the clinical practice of microstructural imaging in different living tissues including, but not limited to, the prostate 55 and muscle fibres 56,57 .…”

Section: Limitations Of the Study And Future Directionsmentioning

confidence: 73%

Validating Pore Size Estimates in a Complex Microfibre Environment on a Human MRI System

Huang

Hsu

Zhou

et al. 2021

Preprint

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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, i.e., non-circular cross-sections, intra-voxel fibre 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 minutes) matched similar protocols used in human studies. The number of distinct fibre 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, fibre configurations and pore size distributions. Irrespective of one or two populations within the voxel, the pore-size estimates (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-fibres. 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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Biomimetic phantom for cardiac diffusion MRI

Cited by 4 publications

References 16 publications

Coaxial electrospun biomimetic copolymer fibres for application in diffusion magnetic resonance imaging

Coaxial electrospun biomimetic copolymer fibres for application in diffusion magnetic resonance imaging

Validating pore size estimates in a complex microfiber environment on a human MRI system

Validating Pore Size Estimates in a Complex Microfibre Environment on a Human MRI System

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