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)

The approach combines: Fast low-angle shot (FLASH) technique for data acquisition [1], which allows for both rapid and continuous imaging without sensitivity to off-resonance artifactsInterleaved radial k-space trajectories for spatial encoding [2], which in contrast to Cartesian data sampling offers motion robustness and moderate tolerance to data undersamplingRegularized nonlinear inversion (NLINV) for image reconstruction [3], 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 protected]