Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Jun 2007
Contrast-dose relation in first-pass myocardial MR perfusion imaging.
To determine the regime of linear contrast enhancement in human first-pass perfusion cardiovascular magnetic resonance (CMR) imaging to improve accuracy in myocardial perfusion quantification. ⋯ Quantitative evaluation of cardiac MR perfusion data needs to account for signal saturation in both the LV blood pool and the myocardium.
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J Magn Reson Imaging · Jun 2007
Misregistration artifacts in image-derived arterial input function in non-echo-planar imaging-based dynamic contrast-enhanced MRI.
To characterize misregistration artifact in arterial input function (AIF) pixels in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using a two-dimensional non-echo-planar imaging (EPI)-based gradient-recalled echo (GRE) sequence. ⋯ AIF misregistration results from a phase shift due to increasing gadolinium concentration in the aorta, and may need to be considered in small animal DCE-MRI studies with a high rate of rise in the AIF in high-field MR applications.
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J Magn Reson Imaging · Jun 2007
Clinical aspects of the apparent diffusion coefficient in 3He MRI: results in healthy volunteers and patients after lung transplantation.
To measure the apparent diffusion coefficient (ADC) after inhalation of hyperpolarized (3)He in healthy volunteers and lung transplant recipients, and demonstrate the gravity dependence of ADC values. ⋯ An anterior-posterior (A/P) gradient was found in inspiration and expiration in healthy lungs. Healthy, transplanted, and native diseased lungs had significantly different mean ADC values. From our preliminary results, (3)He MRI appears to be sensitive for detecting areas of abnormal ventilation in transplanted lungs.
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J Magn Reson Imaging · Jun 2007
High-speed 3T MR spectroscopic imaging of prostate with flyback echo-planar encoding.
Prostate MR spectroscopic imaging (MRSI) at 3T may provide two-fold higher spatial resolution over 1.5T, but this can result in longer acquisition times to cover the entire gland using conventional phase-encoding. In this study, flyback echo-planar readout trajectories were incorporated into a Malcolm Levitt's composite-pulse decoupling sequence (MLEV)-point-resolved spectroscopy sequence (PRESS) to accelerate the acquisition of large array (16 x 16 x 8), high spatial (0.154 cm(3)) resolution MRSI data by eight-fold to just 8.5 minutes. ⋯ Easy data reconstruction and the robustness of the flyback echo-planar encoding make this technique particularly suitable for the clinical setting. The short acquisition time provided by this method reduces the 3T prostate MRI/MRSI exam time, allows longer repetition times, and/or allows the acquisition of additional MR acquisitions within the same exam.
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J Magn Reson Imaging · Jun 2007
Three-dimensional gradient-echo imaging for percutaneous MR-guided laser therapy of liver metastasis.
To evaluate the use of three-dimensional (3D) gradient-echo (GRE) magnetic resonance imaging (MRI) for percutaneous MR-guided catheter placement for laser therapy of liver metastases. ⋯ 3D GRE imaging with the capability to perform multiplanar reconstruction (MPR) shortens the procedure by reducing the number of sequences needed. Improved visibility of the titanium needles allows more precise insertion of multiple needles into the metastasis.