Journal of magnetic resonance imaging : JMRI
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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
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.
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J Magn Reson Imaging · Aug 2008
Comparative StudyComparison of T(1) and T(2) metabolite relaxation times in glioma and normal brain at 3T.
To measure T(1) and T(2) relaxation times of metabolites in glioma patients at 3T and to investigate how these values influence the observed metabolite levels. ⋯ The differential increase in T(2) for Cho and Cr relative to NAA means that the ratios of Cho/NAA and Cr/NAA are higher in tumor at longer echo times (TEs) relative to values in normal appearing brain. Having this information may be useful in defining the acquisition parameters for optimizing contrast between tumor and normal tissue in MR spectroscopic imaging (MRSI) data, in which limited time is available and only one TE can be used.
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J Magn Reson Imaging · Aug 2008
Comparative StudyMonitoring of early response to neoadjuvant chemotherapy in breast cancer with (1)H MR spectroscopy: comparison to sequential 2-[18F]-fluorodeoxyglucose positron emission tomography.
To assess the efficacy of (1)H MR spectroscopy (MRS) to evaluate early responses to neoadjuvant chemotherapy in breast cancer patients, as compared to that of the standardized uptake value (SUV) in (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET). ⋯ A change in the Cho integral value is well correlated with that of peak SUV in the time course of neoadjuvant chemotherapy; thus, breast (1)H MRS is thought to be an alternative to sequential (18)F-FDG PET.
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J Magn Reson Imaging · Aug 2008
Automatic correction of intensity inhomogeneities improves unsupervised assessment of abdominal fat by MRI.
To demonstrate that unsupervised assessment of abdominal adipose tissue distribution by magnetic resonance imaging (MRI) can be improved by integrating automatic correction of signal inhomogeneities. ⋯ The results of this study suggest that the compensation of signal inhomogeneities greatly improves the effectiveness of the unsupervised assessment of abdominal fat. Correction of intensity distortions is important in SAT evaluation and less significant in VAT measurement.