To introduce a novel and generic method for real-time MRI: With high-quality images free of artifactsWith multiple contrastsWith rapid acquisition (as short as 20 ms per image) and high temporal fidelity (frame rate up to 50 Hz)
Methods and Materials
The approach combines: Fast low-angle shot (FLASH) technique for data acquisition , which allows for both rapid and continuous imaging without sensitivity to off-resonance artifactsInterleaved radial k-space trajectories for spatial encoding , which in contrast to Cartesian data sampling offers motion robustness and moderate tolerance to data undersamplingRegularized nonlinear inversion (NLINV) for image reconstruction , which exploits the advantages of parallel imaging with joint update of coil sensitivities and enhances the degree of radial undersampling by another order of magnitude Realization of this technique includes:Implementation...
Real-time MRI of joint movement
Refocused radial FLASH MRI, TR/TE 4.6/2.3 ms (in phase), Flip angle 25°, 73 spokes, acquisition time 336 ms, spatial resolution 0.75x0.75x5 mm3, temporal resolution 3 Hz.
Real-time MRI of swallowing process
Spoiled radial FLASH MRI, TR/TE 2.1/1.4 ms, Flip angle 5°, 25 spokes, acquisition time 52 ms, spatial resolution 1.7x1.7x10 mm3, temporal resolution 20 Hz.
Real-time MRI of cardiovascular movement
Spoiled radial FLASH MRI, TR/TE 2.0/1.3 ms, Flip angle 8°, 11 spokes, acquisition time 22 ms, spatial resolution 2.0x2.0x8 mm3,...
The proposed solution to real-time MRI offers pronounced motion robustness, high image quality, no sensitivities to artifacts as known from alternative high-speed MRI techniques, and flexibility in temporal resolution, spatial resolution, and image contrast.This real-time MRI technology will find many new applications in different areas: Dynamic accessment of myocardial and valve functioning, and (turbulent) blood flow properties in the heart or large vesselsOnline visualization of administration and uptake of contrast agentReal-time monitoring of minimally invasive surgical and interventional procedures, etc.
1. J Frahm et al, German Patent P 3504734.8, Feb 12, 1985. 2. PC Lauterbur, Nature, 242:190-191, 1973. 3. M Uecker et al, Magn Reson Med, 60:674-682, 2008. 4. S Zhang et al, J Magn Reson Imaging, 31:101-109, 2010.5. M Buehrer et al, Magn Reson Med, 58:1131-1139, 2007. 6. M Uecker et al, Magn Reson Med, submitted, 2010.
S. Zhang, M. Uecker, D. Voit, J. Frahm.Biomedizinische NMR Forschungs GmbH, at Max-Planck-Institute for Biophysical Chemistry, Goettingen, GermanyEmail to: email@example.com