Real‐time MRI at a resolution of 20 ms

@article{Uecker2010RealtimeMA,
  title={Real‐time MRI at a resolution of 20 ms},
  author={Martin Uecker and Shuo Zhang and Dirk Voit and Alexander Karaus and Klaus-Dietmar Merboldt and Jens Frahm},
  journal={NMR in Biomedicine},
  year={2010},
  volume={23}
}
The desire to visualize noninvasively physiological processes at high temporal resolution has been a driving force for the development of MRI since its inception in 1973. In this article, we describe a unique method for real‐time MRI that reduces image acquisition times to only 20 ms. Although approaching the ultimate limit of MRI technology, the method yields high image quality in terms of spatial resolution, signal‐to‐noise ratio and the absence of artifacts. As proposed previously, a fast… 

Real-time MRI: recent advances using radial FLASH.

Advanced real-time MRI methods allow for hitherto inaccessible studies, lead to more robust and shorter examinations, improve patient comf… taken together.

On the temporal fidelity of nonlinear inverse reconstructions for real- time MRI – The motion challenge.

NLINV reconstructions offer excellent temporal fidelity as long as the image acquisition time is short enough to adequately sample ("freeze") the object movement, and the motion framework emerges as a valuable tool for the evaluation of real-time MRI methods.

Real-Time Magnetic Resonance Imaging: Radial Gradient-Echo Sequences With Nonlinear Inverse Reconstruction.

Real-time gradient-echo MRI with extreme radial undersampling and nonlinear inverse reconstruction allows for direct monitoring of arbitrary physiological processes and body functions in a variety of clinical scenarios.

Real‐time MRI of speaking at a resolution of 33 ms: Undersampled radial FLASH with nonlinear inverse reconstruction

This application focuses on a dynamic visualization of the main articulators during natural speech production (Standard Modern German) by exploiting a recently developed real‐time MRI technique to address challenges for monitoring speech production at 3 T.

Multiresolution reconstruction of real-time MRI with motion compensated compressed sensing: Application to 2D free-breathing cardiac MRI

A real-time MRI algorithm based on the acquisition of the k-space data following a Golden Radial trajectory, Compressed Sensing reconstruction and a groupwise temporal registration algorithm for the estimation and compensation of the motion in the image, all this embedded within a temporal multiresolution scheme is described.

Rapid Diffusion-Weighted Magnetic Resonance Imaging of the Brain Without Susceptibility Artifacts: Single-Shot STEAM With Radial Undersampling and Iterative Reconstruction

The proposed method for DW MRI offers immunity against susceptibility problems, high spatial resolution, adequate signal-to-noise ratio and clinically feasible scan times of less than 3 minutes for whole-brain studies.

FLASHlight MRI in real time—a step towards Star Trek medicine

: This work describes a dynamic magnetic resonance imaging (MRI) technique for local scanning of the human body with use of a handheld receive coil or coil array. Real-time MRI is based on highly

Advances in real-time phase-contrast flow MRI and multi-echo radial FLASH

A novel model-based reconstruction technique, which directly estimates and regularizes the phase-contrast map from the measured datasets based on a proper signal modeling and hence ensures zero phase in the areas without MR signals, is developed.

Novel MR image recovery using patch-smoothness iterative shrinkage algorithm

The designed schemes aim to achieve a shorter scan duration, higher spatial resolution, increased temporal resolution, signal-to-noise ratio and coverage in multidimensional multichannel MRI, and improve patients comfort and compliance while imaging under the MRI device.

Fast 3D contrast enhanced MRI of the liver using temporal resolution acceleration with constrained evolution reconstruction

Preliminary in vivo results demonstrated high spatial resolution dynamic three‐dimensional images of the whole liver with high frame rates, from which numerous subarterial phases could be easily identified retrospectively.
...

References

SHOWING 1-10 OF 29 REFERENCES

Nonlinear inverse reconstruction for real‐time MRI of the human heart using undersampled radial FLASH

An extension of the nonlinear inverse algorithm to non‐Cartesian k‐space encodings, its implementation on a graphicalprocessing unit to reduce reconstruction times, and the use of a convolution‐based iteration, which considerably simplifies the graphical processing unit implementation compared to a gridding technique are introduced.

Continuous radial data acquisition for dynamic MRI

This work presents an approach to realtime imaging using a continuous radial acquisition scheme and the intrinsic advantages of radial or projection reconstruction (PR) techniques are used to minimize motion‐related image distortions.

Highly constrained backprojection for time‐resolved MRI

A simple non‐iterative unfiltered backprojection algorithm that incorporates the idea of a composite image consisting of portions or all of the acquired data to constrain the back projection process is presented, which significantly reduces streak artifacts and increases the overall SNR.

Image reconstruction by regularized nonlinear inversion—Joint estimation of coil sensitivities and image content

A respective algorithm based on a Newton‐type method with appropriate regularization terms is demonstrated to improve the performance of autocalibrating parallel MRI—mainly due to a better estimation of the coil sensitivity profiles.

RARE imaging: A fast imaging method for clinical MR

Based on the principles of echo imaging, a method is proposed to acquire sufficient data for a 256 × 256 image in from 2 to 40s, and the signal amplitudes of structures with long T2 are nearly the same as those in a conventional 2D FT experiment.

Undersampled radial MRI with multiple coils. Iterative image reconstruction using a total variation constraint

An iterative reconstruction method for undersampled radial MRI which is based on a nonlinear optimization, allows for the incorporation of prior knowledge with use of penalty functions, and deals with data from multiple coils is developed.

SENSE: Sensitivity encoding for fast MRI

The problem of image reconstruction from sensitivity encoded data is formulated in a general fashion and solved for arbitrary coil configurations and k‐space sampling patterns and special attention is given to the currently most practical case, namely, sampling a common Cartesian grid with reduced density.

MR fluoroscopy: Technical feasibility

It is shown how the sliding window technique lends itself to high‐speed reconstruction, with each newly acquired echo used to quickly update the image on display to result in realtime MR image acquisition and reconstruction.

Rapid NMR imaging of dynamic processes using the FLASII technique

FLASH (Fast Low‐Angle SHot) imaging is a new method for rapid NMR imaging which has been demonstrated to provide abdominal images without artifacts due to respiratory or peristaltic motions. The

Rapid NMR imaging using stimulated echoes