Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Sep 2007
Positional lumbar imaging using a positional device in a horizontally open-configuration MR unit - initial experience.
To evaluate whether positional MR images of the lumbar spine, obtained with a horizontally open-configuration MR unit, demonstrate positional changes of the dural sac, and to assess whether there are significant differences in positional changes between healthy volunteers and patients with chronic low back pain. ⋯ Using a horizontally open-configuration MR unit, positional MR imaging provided position-dependent change of the dural sac. Positional changes at the site of the degenerated disks may be different in patients with and without chronic low back pain.
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J Magn Reson Imaging · Sep 2007
Cepstral estimation of arterial input functions in brain perfusion imaging.
To investigate voxel-specific arterial input functions (AIFs) obtained through blind deconvolution using complex cepstrum liftering. Blindly estimated AIFs have the potential of reducing dispersion effects in perfusion maps and are completely user-independent. ⋯ The overlap of AIFs and TRFs in the complex cepstrum makes reliable separation of the two functions more difficult than previously described. Comparison to noncepstral blind methods suggests that similar optima are found using the new separation filter.
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J Magn Reson Imaging · Aug 2007
Evaluation of optimal echo time for 1H-spectroscopic imaging of brain tumors at 3 Tesla.
To compare the spectral quality of short echo time (TE) MR spectroscopic imaging (MRSI, TE = 30 msec) with long-TE MRSI (TE = 144 msec) at 3 Tesla in normal brain and tumor tissue. ⋯ Since other metabolites observable at TE < 30 msec may be of diagnostic relevance, short-TE MRSI should be the preferred method at 3T for the evaluation of focal lesions in brain tissue; however, TE = 144 msec can serve as an option for MRS in regions with potential baseline problems.
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J Magn Reson Imaging · Aug 2007
Focal pancreatic mass: distinction of pancreatic cancer from chronic pancreatitis using gadolinium-enhanced 3D-gradient-echo MRI.
To determine the accuracy of MRI including T1-weighted gadolinium (Gd)-enhanced three-dimensional-gradient-echo (3D-GE) sequences to distinguish pancreatic cancer from chronic pancreatitis in patients with pancreatic mass or focal enlargement. ⋯ MRI including Gd-enhanced T1-weighted 3D-GE sequences can differentiate pancreatic carcinoma from chronic pancreatitis successfully in most cases.
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J Magn Reson Imaging · Aug 2007
Image quality and focal lesion detection on T2-weighted MR imaging of the liver: comparison of two high-resolution free-breathing imaging techniques with two breath-hold imaging techniques.
To evaluate image quality and accuracy for the detection of focal hepatic lesions depicted on T2-weighted images obtained with two high-resolution free-breathing techniques (navigator-triggered turbo spin-echo [TSE] and respiratory-triggered TSE) and two standard-resolution breath-hold techniques (breath-hold TSE with restore pulse and half-Fourier acquisition single-shot TSE [HASTE]). ⋯ High-resolution, free-breathing, T2-weighted MRI techniques can significantly improve the detectability of focal hepatic lesions and provide higher lesion-to-liver contrast of solid lesions compared to breath-hold techniques.