A5079324754- Advanced MRI Techniques and Applications
- Electron Spin Resonance Studies
- Medical Imaging Techniques and Applications
- Advanced NMR Techniques and Applications
- MRI in cancer diagnosis
- Advanced Electron Microscopy Techniques and Applications
- Medical Image Segmentation Techniques
- NMR spectroscopy and applications
- Particle Accelerators and Free-Electron Lasers
- Microwave Imaging and Scattering Analysis
- Advanced Neuroimaging Techniques and Applications
- Genetic Neurodegenerative Diseases
- Sparse and Compressive Sensing Techniques
- Electromagnetic Compatibility and Noise Suppression
- Ultrasound and Hyperthermia Applications
- Atomic and Subatomic Physics Research
- Digitalization, Law, and Regulation
- Seismic Imaging and Inversion Techniques
- Radiomics and Machine Learning in Medical Imaging
- Radio Frequency Integrated Circuit Design
- Physics and Engineering Research Articles
- German Security and Defense Policies
- Public Administration and Political Analysis
- Cardiac Imaging and Diagnostics
- Electromagnetic Compatibility and Measurements
German Center for Neurodegenerative Diseases
2022-2025
T
Abstract Purpose Brain segmentation and multi‐parameter mapping (MPM) are important steps in neurodegenerative disease characterization. However, acquiring both a high‐resolution T1w sequence like MPRAGE (standard input to brain segmentation) an MPM the same neuroimaging protocol increases scan time patient discomfort, making it difficult combine clinical examinations. Methods A novel approach synthesize images from images, named , is proposed compared standard technique used produce...
Abstract Purpose Chemical exchange saturation transfer (CEST) measurements at ultra‐high field (UHF) suffer from strong inhomogeneity. Retrospective correction of this inhomogeneity is possible to some extent, but requires a time‐consuming repetition the measurement. Here, we propose calibration‐free parallel transmit (pTx)‐based scheme that homogenizes over imaging volume, which call PUlse design for Saturation Homogeneity utilizing Universal Pulses (PUSHUP). Theory Magnetization effects...
Purpose We present a time‐efficient water‐selective, parallel transmit RF excitation pulse design for ultra‐high field applications. Methods The proposed method achieves flip angle homogenization at fields by employing spatially nonselective ‐points pulses. In order to introduce water‐selection, the concept of binomial pulses is applied. Due composite nature ‐points, can be split into multiple subpulse blocks shorter than half precession period fat, that are played out successively....
Multi-Slice T2-weighted MR imaging is a fundamental technique in brain but suffers from field inhomogeneities at ultra-high systems. In this work we present pulse design method which provides slab-selective universal pulses with phase-coherent excitation profiles over selected regions. Applied 3D variable flip angle turbo-spin-echo (TSE) sequence, the achieve superior SNR compared to multi-slice TSE and B1+ inhomogeneity mitigation.
RF transmit field inhomogeneities at 7T usually degrade the image quality in regions such as cerebellum and brainstem, which has so far delayed its use to study cerebellar ataxias with higher fields. We present an optimized pipeline that maximizes QSM contrast of nuclei based on multi-echo MPM data. show averaging individual susceptibility maps increases signal-to-noise ratio (SNR) reduces group standard deviation. introduced a weighted acquisition SNRs. Final presented high dentate nucleus...
CEST imaging benefits from the increased spectral resolution at ultra-high field. Due to inhomogeneous RF field, a B1+-correction is necessary, which requires repeated measurements. The number of required repetitions can be reduced two by using ptx-based saturation scheme, like MIMOSA. We present an alternative scheme that based on PUSH and universal pulses, we name PUSHUP. Using this approach, could reduce inhomogeneity as effectively MIMOSA while being more SAR efficient.
We present a versatile high-resolution whole-brain multiparametric/susceptibility mapping protocol at 7T, introducing interleaved fly-back skipped-CAIPI 3D-EPI. To overcome the impeding limitations of B1+ inhomogeneity, universal pTX pulses for excitation and magnetization transfer saturation are employed. Within 17 minutes scan time, 0.6mm isotropic MT-/PD-/T1-weighted magnitude phase images four echo times corresponding quantitative parameter maps obtained. Supplementary output, like SWI...
We present single channel universal GRAPE pulses for optimized T1 and T2 weighted (fluid suppressed) imaging on clinical ultra-high field systems. B0 B1 inhomogeneities are effectively mitigated while no pulse calculations necessary during the session. Compared to a parallel transmission set-up SAR estimation is less complex, with more established history of safe use, it makes this approach promising tool applications such as lesion detection.
Motivation: CEST suffers from saturation inhomogeneities, especially at ultra-high fields. Universal pulses enable calibration-free mitigation of these inhomogeneities. However, it is not obvious how well PUSHUP translates to different scanners. Goal(s): The goal this work evaluate the feasibility PUSHUP-CEST obtain homogeneous whole-brain, high-resolution maps in multi-center studies. Approach: was calculated using a joined database three sites. Multiple measurements were performed each...
Motivation: 2D multi-slice diffusion-weighted MRI (dMRI) suffers from severe signal non-uniformity caused by B1+ inhomogeneity at ultra-high fields. Goal(s): To design a 3D dMRI sequence with Universal parallel transmission radio-frequency Pulses (UPs) to improve image uniformity across the brain 7T without lengthening workflow. Approach: We propose spin-echo an inversion pulse before excitation enhance SNR. UPs were designed for inversion, excitation, and refocussing implemented in...
Motivation: Using single-channel transmit coils, the $$$B_1$$$ distribution is very inhomogenous in brain. This leads to flipangle variations and consequently signal loss a large portion of parallel these might be mitigated. Goal(s): The goal this work develop universal slab-selective homogeneuos excitation pulses for whole-brain MRSI acquisitions. Approach: Slab-selective $$$k_t$$$ points have been calculated under consideration multiple off-center frequencies. Flip angle homogeneity phase...
Motivation: Brain segmentation and multiparameter mapping (MPM) are important for neurodegenerative disease characterization. Acquiring sub-millimeter images increases scan time patient discomfort. At 7T, B1+ inhomogeneities challenge brain segmentation. Goal(s): The quality of segmentations produced from FastSurferVINN was evaluated compared between a 7T MPRAGE protocol two synthetic approaches. Approach: MPM were acquired on 16 subjects across three sites using pTx pulses. MPRAGElike...
Motivation: MPRAGE is the standard high-resolution T1w sequence used for anatomical MRI. Very few sequences propose such a high Gray-White matter contrast with high-resolution. Goal(s): Propose novel technique that computes MPRAGElike images if spoiled GRE different (and more) contrasts are available. Approach: and Multi-Parameter Mapping (MPM) were acquired on 16 subjects across three 7T sites. MPM to produce variations of one synMPRAGE images. SNR CNR evaluated against MPRAGE. Results: Our...