Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Sep 2008
Diffusion tensor imaging of the auditory pathway in sensorineural hearing loss: changes in radial diffusivity and diffusion anisotropy.
To prospectively compare diffusion tensor imaging (DTI) measures of axial diffusivity (lambda parallel), radial diffusivity (lambda perpendicular), mean diffusivity (MD), and fractional anisotropy (FA) along the auditory pathway of patients with sensorineural hearing loss (SNHL) and normal controls. ⋯ In SNHL patients DTI showed a high radial diffusivity that consequently led to a decreased fractional anisotropy in the LL and the IC.
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To develop a T1rho-prepared, balanced gradient echo (b-GRE) pulse sequence for rapid three-dimensional (3D) T1rho relaxation mapping within the time constraints of a clinical exam (<10 minutes), examine the effect of acquisition on the measured T1rho relaxation time and optimize 3D T1rho pulse sequences for the knee joint and spine. ⋯ The T1rho-prepared b-GRE acquisition rapidly and reliably accelerates T1rho quantification of tissues offset partially by a TSL-dependent point spread function.
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To apply diffusion tensor images using 30 noncollinear directions for diffusion-weighted gradient schemes to characterize diffusion tensor imaging (DTI) features associated with C6 glioma-bearing rat brains, and ideally visualize fiber tractography datasets. ⋯ We have demonstrated in this study that fiber tractography with the 30 noncollinear diffusion gradient scheme method can be used to help provide a better understanding regarding the influence of a tumor on the surrounding regions of normal brain tissue in vivo.
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J Magn Reson Imaging · Sep 2008
Fast projective carotid MR angiography using arterial spin-labeled balanced SSFP.
To determine whether pulsed arterial spin-labeled (pulsed ASL) balanced steady-state free precession (bSSFP) imaging allows for rapid projective depiction of the carotid arteries without electrocardiographic (ECG) gating. ⋯ pulsed ASL bSSFP is a fast technique for projective carotid angiography that may not require ECG gating. Acquisition time may be decreased with reduced FOV or parallel imaging strategies.
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J Magn Reson Imaging · Sep 2008
Investigation and optimization of parameter accuracy in dynamic contrast-enhanced MRI.
To present a modified pharmacokinetic model for improved parameter accuracy and to investigate the influence of an inaccurate arterial input function (AIF) on dynamic contrast-enhanced (DCE)-MRI parameter estimates of the transfer constant (Ktrans), blood volume (vp), and interstitial volume (ve). ⋯ While an accurate, high temporal resolution AIF is essential for estimating vp, a biexponential AIF acquired at low temporal resolution (<20 seconds) provides robust estimates of ve and results in a Ktrans underestimation comparable to that from a 25% error in the initial AIF bolus amplitude.