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Two strategies for the optimization of centric scan SPRITE (single point ramped imaging with T1 enhancement) magnetic resonance imaging techniques are presented. Point spread functions (PSF) for the centric scan SPRITE methodologies are numerically simulated, and the blurring manifested in a centric scan SPRITE image through PSF convolution is(More)
MRI is proving to be a very useful tool for sodium quantification in animal models of stroke, ischemia, and cancer. In this work, we present the practical design of a dual-frequency RF surface coil that provides (1)H and (23)Na images of the rat head at 4 T. The dual-frequency RF surface coil comprised of a large loop tuned to the (1)H frequency and a(More)
A prototype of a new bimodal scanner was installed in our laboratory. This scanner combines magnetic resonance imaging (MRI) and positron emission tomography (PET) for brain studies. As the PET detector is located within the bore of the MRI scanner, simultaneous measurements become possible. The MR-component consists of a commercial 3T MRI scanner MAGNETOM(More)
Diffusion tensor imaging (DTI) permits non-invasive probing of tissue microstructure and provides invaluable information in brain diagnostics. Our aim was to examine approaches capable of capturing more detailed information on the propagation mechanisms and underlying tissue microstructure in comparison to the conventional methods. In this work, we report a(More)
Diffusion-weighted magnetic resonance imaging provides access to fiber pathways and structural integrity in fibrous tissues such as white matter in the brain. In order to enable better access to the sensitivity of the diffusion indices to the underlying microstructure, it is important to develop artificial model systems that exhibit a well-known structure,(More)
A new algorithm is proposed for computing the discrete Fourier Transform (DFT) of purely phase encoded data acquired during Magnetic Resonance Imaging (MRI) experiments. These experiments use the SPRITE (Single Point Ramped Imaging with <i>T</i><sub>1</sub> Enhancement) method and multiple-point acquisition, sampling data in a nonuniform manner that(More)
Residual magnetisation is one of the major sources of artefacts in single point imaging sequences with short repetition times. The unwanted signal is caused by non-dephased transverse magnetisation excited in preceding acquisition cycles. Therefore, the problem emerges mainly around the centre of k-space and has been solved in the past by additional(More)
Simultaneous, hybrid MR-PET is expected to improve PET image resolution in the plane perpendicular to the static magnetic field of the scanner. Previous papers have reported this either by simulation or experiment with simple sources and detector arrangements. Here, we extend those studies using a realistic brain phantom in a recently installed MR-PET(More)
The Single Point Ramped Imaging with T1 Enhancement (SPRITE) sequence is well suited for the acquisition of magnetic resonance signals from fast relaxing nuclei and from heterogeneous materials. However, it is time inefficient compared to sequences that are based on frequency encoding because only one single point is acquired per excitation. Multiple-point(More)
Diffusion tensor imaging is an important method for noninvasively acquiring structural information of the human brain. For advanced fiber tracking, the acquisition of diffusion-weighted (DW) images has to be performed along many different spatial directions, resulting in long scan times. Therefore, the ultra-fast imaging method, echo-planar imaging (EPI),(More)