Cerebrospinal diffusion phantom

Patent metadata

Field	Value
Publication number	US-9880251-B2
Application number	US-201515102448-A
Country	US
Kind code	B2
Filing date	Sep 4, 2015
Priority date	Sep 4, 2015
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

Disclosed herein are cerebrospinal diffusion phantoms which include a housing having a shape and size configured for insertion into a magnetic resonance coil in one or more preselected poses. A scaffold support structure is mounted on an interior of said housing and a plurality of elongated diffusion mimicking members supported on the support array. The elongated diffusion mimicking members are affixed to the scaffold support structure such that elongated diffusion mimicking members extend in directions needed to substantially emulate a 3 dimensional arrangement of cerebrospinal diffusion fiber tracts in a living organism; as well as modules for elimination of resolution based-bias, angular accuracy evaluation, diffusion rate calibration, and quality assurance image referencing. Each elongated diffusion mimicking member includes an aqueous component which can undergo diffusion along the elongated diffusion mimicking member. The phantom includes a cerebrospinal tissue mimic matrix material contained in the housing enveloping the array of elongated diffusion mimicking members. The housing is made of a material whose magnetic susceptibility substantially matches that of the cerebrospinal mimic matrix material.

First claim

What is claimed is:

1. A cerebrospinal diffusion phantom, comprising:
a) an external housing having a shape and size configured for insertion into a magnetic resonance coil in one or more preselected poses,
b) a sealable internal housing enclosed in said external housing;
c) a modular reconfigurable scaffold support structure mounted on an interior of said inner housing;
d) a plurality of elongated diffusion mimicking members supported on said reconfigurable scaffold support structure, said plurality of elongated diffusion mimicking members affixed to said reconfigurable scaffold support structure such that elongated diffusion mimicking members extend in directions needed to substantially emulate a 3 dimensional (3D) arrangement of cerebrospinal diffusion fiber tracts in a living organism each elongated diffusion mimicking member including an aqueous component which can undergo diffusion along said elongated diffusion mimicking member;
e) a cerebrospinal tissue mimic matrix material contained and sealed in said interior housing enveloping said plurality of elongated diffusion mimicking members, said inner and outer housings being made of a material whose magnetic susceptibility substantially matches that of said cerebrospinal tissue mimic matrix material.

2. The phantom according to claim 1 including an air gap located between an outer surface of said inner housing and an inner surface of said external housing that acts as a passive thermal insulator so as to reduce a rate of temperature fluctuation between said cerebrospinal tissue mimic matrix material and said outer housing.

3. The phantom according to claim 1 wherein said elongated diffusion mimicking members are flexible micro-rod bundles having an assembly of micro-rods with uniform and varying cross-sectional planform so as to generate micro-lumen structures that are filled with aqueous solution.

4. The phantom according to claim 1 wherein said elongated diffusion mimicking members are flexible pulled micro-rods having a two or more channels formed in an outer surface thereof and extending along a length of the micro-rods to give a surface area that is higher compared to the flexible pulled micro-rods not having said two or more channels.

5. The phantom according to claim 4 wherein said two or more channels having a size selected to be of a size to be narrow in comparison to the distance water can diffuse on the timescale of a DTI protocol, thereby restricting the possible diffusion in all directions except for along the direction of the fiber.

6. The phantom according to claim 5 wherein said two or more channels having a size in a range from about 0.5 to about 10 micrometers.

7. The phantom according to claim 4 wherein said one or more elongated diffusion mimicking members is a plurality of said flexible pulled micro-rods bundled together to form flexible micro-rod bundles.

8. The phantom according to claim 1 wherein said cerebrospinal mimic matrix material is any one or combination of a polyvinyl alcohol cryogel (PVA-C), solution, water, or a cross-linked polyacrylate polymer gel.

9. The phantom according to claim 8 wherein each elongated diffusion mimicking member is comprised of a plurality of flexible micro-rod elements, and wherein said aqueous component is a thin layer of water enveloping said flexible micro-rod elements such that when said phantom is placed in a magnetic field in an MR machine, diffusion of water molecules in said thin layer of water enveloping said flexible micro-rod elements takes place.

10. The phantom according to claim 1 wherein said aqueous component includes water alone.

11. The phantom according to claim 1 wherein said aqueous component includes water and a contrast agent selected to reduce magnetic susceptibility differences between the aqueous component and a material of which said elongated diffusion mimicking members are made from.

12. The phantom according to claim 1 wherein said external and internal housings are configured to be releasably coupled to each other, and including an inlet port for filling said internal housing when the external and internal housings are decoupled from each other.

13. The phantom according to claim 1 wherein said housing includes one or more planar sections for resting on a flat surface when inserted into a magnetic coil of an MRI machine, and wherein said one or more planar sections located on said housing is correlated with said 3 dimensional arrangement of cerebrospinal diffusion fiber tracts in the living organism.

14. The phantom according to claim 1 wherein said external housing includes hand graspable features for holding said phantom.

15. The phantom according to claim 1 further comprising one or more markers or landmarks located on an exterior surface of said outer or inner housing for landmarking a preselected orientation of the phantom in the MR coil.

16. The phantom according to claim 1 further comprising one or more temperature sensors on the outer housing to indicate external temperature.

17. The phantom according to claim 1 wherein said modular reconfigurable scaffold support structure is configured to releasably hold said plurality of elongated diffusion mimicking members in a variety of 3 dimensional configurations for emulating fiber tracts of different living organisms.

18. The phantom according to claim 1 wherein said external housing has a size and shape reflective of a human head, and wherein said cerebrospinal tissue mimic matrix material contained in said inner housing is selected to mimic preselected biomechanical properties of a human brain.

19. The phantom according to claim 1 further comprising a resolution module mounted on the interior of the inner housing which is configured to enable an MR technician to tune MR machine protocols to obtain a desired DTI resolution.

20. The phantom according to claim 1 further comprising a Q-ball imaging module mounted on the interior of said inner housing for evaluation of angular accuracy of tractography in diffusion tensor imaging (DTI).

21. The phantom according to claim 1 further comprising an isotropic diffusion module mounted on the interior of said inner housing for calibration of multiple different isotropic diffusion rates.

22. The phantom according to claim 1 further comprising a quality assurance module configured for referencing phantom to images from known protocols.

23. The phantom according to claim 1 further comprising a module for determining high-contrast spatial resolution.

24. A method for generating biomimetic micro-lumen structure containing bundles of flexible micro-rods from multi-material elements, comprising:
providing a bobbin of bicomponent micro-rods comprised of micro-rods of insoluble material embedded in a matrix of soluble material, unwinding the biocomponent micro-rod strand from said bobbin and winding it onto a generally square shaped spindle to generate a bicomponent micro-rod bundle with a set number of aligned bicomponent micro-rod strands, and said rod bundle having opposed ends;
immersing the rod bundle in water to dissolve the matrix of soluble material and thereafter placing the rod bundle in an ultrasonication bath, and repeating until all the soluble material has been removed and water is entrapped between adjacent micro-rods of insoluble material;
applying tension to the rod bundle by pulling the opposed ends of said rod bundle in opposite directions to align the micro-rods with each other i

Assignees

• Kerins Fergal
• Gmeiner Timotheus Anton
• Stainsby Jeff Alan
• Harris Chad Tyler
• Thingvold Sheryl Rae
• Whitton Gregory Allan
• Synaptive Medical Barbados Inc

Inventors

• Kerins Fergal
• Gmeiner Timotheus Anton
• Stainsby Jeff Alan
• Harris Chad Tyler
• Thingvold Sheryl Rae
• Whitton Gregory Allan

Classifications

• A61B5/055

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title

• G09B23/30 Primary

  Anatomical models {(G09B23/281 - G09B23/288 take precedence)} · CPC title

• G01R33/56341

  Diffusion imaging · CPC title

• G01R33/4806

  Functional imaging of brain activation · CPC title

• G01R33/58 Primary

  Calibration of imaging systems, e.g. using test probes {, Phantoms; Calibration objects or fiducial markers such as active or passive RF coils surrounding an MR active material} · CPC title