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NONINVASIVE IMAGING OF BRAIN VASCULATURE WITH HIGH RESOLUTION BLOOD OXYGENATION LEVEL-DEPENDENT VENOGRAPHY IN MAGNETIC RESONANCE IMAGING: APPLICATIONS TO FUNCTIONAL AND CLINICAL STUDIES

Park, Sung-Hong (2009) NONINVASIVE IMAGING OF BRAIN VASCULATURE WITH HIGH RESOLUTION BLOOD OXYGENATION LEVEL-DEPENDENT VENOGRAPHY IN MAGNETIC RESONANCE IMAGING: APPLICATIONS TO FUNCTIONAL AND CLINICAL STUDIES. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Abstract

BOLD techniques have been used in a vast range of applications including functional MRI (fMRI) and clinical MR venography of brain vasculature. Despite the immense success of BOLD fMRI applications, our understanding of complex neuronal and hemodynamic processes associated with BOLD techniques is limited. An experimental investigation with BOLD MR venography may allow us to expand our knowledge in hemodynamic process involved in BOLD fMRI. BOLD techniques are also clinically useful. In clinical brain imaging studies, imaging both time-of-flight (TOF) MR angiogram (MRA) and BOLD MR venogram (MRV) is often desirable, because they complement the depiction of vascular pathologies. Nevertheless, MRV is usually not acquired to minimize the image acquisition time. It will be highly beneficial if we can acquire MRV while imaging MRA without increasing scan time. Thus, the objective of our study was to develop and assess BOLD MRV techniques for both functional and clinical applications. For the experimental evaluation of BOLD MRV, we used a rat brain model at 9.4T. The scan condition for BOLD MRV was optimized and the venous origin of hypointense vasculature was investigated with modulation of oxygenation. Detailed venules of ˜16-30μm diameter were detected in the resulting in vivo images with 78μm isotropic scan resolution, verified with in vivo two-photon microscopy and computer simulation data. Activation foci of high-resolution BOLD fMRI maps were correlated with relatively large intracortical veins detected with high-resolution BOLD MRV, indicating that detectability of conventional BOLD fMRI is limited by density of these intracortical veins (˜1.5 vessels/mm²). For the clinical application of BOLD MRV, we developed and tested a compatible dual-echo arteriovenography (CODEA) technique for simultaneous acquisition of TOF MRA and BOLD MRV at a 3T human system. Image quality of the CODEA technique acquired in a single session was comparable to conventional TOF MRA and BOLD MRV separately acquired in two sessions. The CODEA technique was applied to chronic stroke studies. Detailed vascular structures including arterial occlusions and venous abnormalities were depicted. The CODEA technique appears valuable to other clinical applications, particularly for those requiring efficient MRA/MRV imaging with limited scan time such as acute stroke studies.


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Park, Sung-Hongsup6@pitt.eduSUP6
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairBae, Kyongtae Tybaek@upmc.eduKTB4
Committee MemberNemoto, Edwin Mnemotoem@upmc.edu
Committee MemberStetten, Georgegeorge@stetten.com
Committee MemberHe, Quihonghe_qiuhong@hotmail.com
Date: 25 September 2009
Date Type: Completion
Defense Date: 10 April 2009
Approval Date: 25 September 2009
Submission Date: 13 April 2009
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Bioengineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: BOLD; CODEA; fMRI; high field; microvasculature; stroke; susceptibility-weighted imaging; time-of-flight; two-photon microscopy; venography
Other ID: http://etd.library.pitt.edu/ETD/available/etd-04132009-150558/, etd-04132009-150558
Date Deposited: 10 Nov 2011 19:37
Last Modified: 19 Dec 2016 14:35
URI: http://d-scholarship.pitt.edu/id/eprint/7123

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