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A Slowly Progressive and Reproducible Animal Model of Intervertebral Disc Degeneration Characterized by MRI:Development of a Custom Quad Coil For High Resolution Scanning at 3.0T

Kompel, John Francis (2008) A Slowly Progressive and Reproducible Animal Model of Intervertebral Disc Degeneration Characterized by MRI:Development of a Custom Quad Coil For High Resolution Scanning at 3.0T. Master's Thesis, University of Pittsburgh.

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    Abstract

    STUDY DESIGN: The progression of intervertebral disc degeneration (IDD) follows anterolateral "stab" of adult rabbit lumbar discs by 16-gauge hypodermic needle to a limited (5-mm) depth was studied for up to 24 weeks using magnetic resonance imaging (MRI).OBJECTIVES: To develop a slowly progressive, reproducible rabbit model of IDD suitable for studying pathogenesis and pathopysiology of intervertebral disc degeneration. Moreover, to improve the MRI methods and achieve improved MRIs a custom quad coil tuned and matched for 3.0T was developed. Higher SNR achievable with this coil allowed the acquisition of higher resolution images.METHODS: Part1 - The L2-L3, L3-L4, and L4-L5 lumbar intervertebral discs of 18 skeletally mature female New Zealand White (NZW) rabbits were stabbed by 16-gauge hypodermic needle to a depth of 5-mm in the left anterolateral annulus fibrosis (AF). Serial MRI scans of the stabbed discs and intact L1-2 and L5-6 control discs were performed at 3, 6, 12, and 24 weeks post surgery and compared with preoperative MRIs. Development of the quad coil at 3.0T was competed with reference phantom to demonstrate the advantages over the 5 inch surface coil at 1.5T. To further illustrate the coils advantages in-vivo rabbit MRIs were obtained with the custom coil and compared to the 5 inch surface coil at 1.5TRESULTS: The stabbed discs exhibited a progressive decrease in "MRI Index" (the product of nucleus pulposus (NP) area and signal intensity from T2-weighted midsagittal plane images) starting at 3 weeks post stab and continuing through 24 weeks, with no evidence of spontaneous recovery or reversal of MRI changes. In addition, the constructed quad coil at 3.0T demonstrated the ability to obtain high resolution scans with SNR comparable to the 5 inch surface coil at 1.5T.CONCLUSIONS: Stabbing the anterolateral AF of adult rabbit lumbar discs with a 16-gauge hypodermic needle to a limited (5-mm) depth results in a number of slowly progressive and reproducible MRI changes over 24 weeks that show a similarity to changes seen in human IDD. This model would appear suitable for studying pathogenesis and pathophysiology of IDD and testing safety and efficacy of novel treatments of IDD.


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    Item Type: University of Pittsburgh ETD
    Creators/Authors:
    CreatorsEmailORCID
    Kompel, John Francisjfkst20@pitt.edu
    ETD Committee:
    ETD Committee TypeCommittee MemberEmailORCID
    Committee ChairGilbertson, Lars Ggilbertsonl@upmc.edu
    Committee MemberRobertson, Doug
    Committee MemberBoada, Fernando
    Committee MemberKang, James Dkangjd@upmc.edu
    Title: A Slowly Progressive and Reproducible Animal Model of Intervertebral Disc Degeneration Characterized by MRI:Development of a Custom Quad Coil For High Resolution Scanning at 3.0T
    Status: Unpublished
    Abstract: STUDY DESIGN: The progression of intervertebral disc degeneration (IDD) follows anterolateral "stab" of adult rabbit lumbar discs by 16-gauge hypodermic needle to a limited (5-mm) depth was studied for up to 24 weeks using magnetic resonance imaging (MRI).OBJECTIVES: To develop a slowly progressive, reproducible rabbit model of IDD suitable for studying pathogenesis and pathopysiology of intervertebral disc degeneration. Moreover, to improve the MRI methods and achieve improved MRIs a custom quad coil tuned and matched for 3.0T was developed. Higher SNR achievable with this coil allowed the acquisition of higher resolution images.METHODS: Part1 - The L2-L3, L3-L4, and L4-L5 lumbar intervertebral discs of 18 skeletally mature female New Zealand White (NZW) rabbits were stabbed by 16-gauge hypodermic needle to a depth of 5-mm in the left anterolateral annulus fibrosis (AF). Serial MRI scans of the stabbed discs and intact L1-2 and L5-6 control discs were performed at 3, 6, 12, and 24 weeks post surgery and compared with preoperative MRIs. Development of the quad coil at 3.0T was competed with reference phantom to demonstrate the advantages over the 5 inch surface coil at 1.5T. To further illustrate the coils advantages in-vivo rabbit MRIs were obtained with the custom coil and compared to the 5 inch surface coil at 1.5TRESULTS: The stabbed discs exhibited a progressive decrease in "MRI Index" (the product of nucleus pulposus (NP) area and signal intensity from T2-weighted midsagittal plane images) starting at 3 weeks post stab and continuing through 24 weeks, with no evidence of spontaneous recovery or reversal of MRI changes. In addition, the constructed quad coil at 3.0T demonstrated the ability to obtain high resolution scans with SNR comparable to the 5 inch surface coil at 1.5T.CONCLUSIONS: Stabbing the anterolateral AF of adult rabbit lumbar discs with a 16-gauge hypodermic needle to a limited (5-mm) depth results in a number of slowly progressive and reproducible MRI changes over 24 weeks that show a similarity to changes seen in human IDD. This model would appear suitable for studying pathogenesis and pathophysiology of IDD and testing safety and efficacy of novel treatments of IDD.
    Date: 30 January 2008
    Date Type: Completion
    Defense Date: 14 April 2005
    Approval Date: 30 January 2008
    Submission Date: 06 April 2006
    Access Restriction: No restriction; The work is available for access worldwide immediately.
    Patent pending: No
    Institution: University of Pittsburgh
    Thesis Type: Master's Thesis
    Refereed: Yes
    Degree: MSBeng - Master of Science in Bioengineering
    URN: etd-04062006-222447
    Uncontrolled Keywords: fast-spin echo; k-space; magnetism; resonance; spin echo; T2-weighted
    Schools and Programs: Swanson School of Engineering > Bioengineering
    Date Deposited: 10 Nov 2011 14:34
    Last Modified: 20 Apr 2012 10:50
    Other ID: http://etd.library.pitt.edu/ETD/available/etd-04062006-222447/, etd-04062006-222447

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