Real-time MRI

The real-time magnetic resonance imaging (real-time MRI) (also MR fluoroscopy ) is a method on the basis of magnetic resonance imaging for the continuous monitoring of a moving object in real time , that is for representing a motion as an image series or MRI-movie.

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Real-time MRI of the human heart (short axis view) with 33 ms time resolution

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Real-time MRI of the human heart (two-chamber view) with 22 ms time resolution

The basis is the FLASH 2 technology from Jens Frahm and colleagues in Göttingen.

Applications

The clinical and scientific applications of real-time MRI range from cardiac imaging to functional examinations of the brain ( fMRI ) and joints (e.g. temporomandibular joint , knee joint ) or the complex sequence of movements of the muscles in the mouth, throat and throat area Talking or swallowing . In addition, there are uses in abdominal imaging and interventional MRI (see also interventional radiology ), which enable non-invasive image control in minimally invasive operations. Real-time MRI can also be used in the non-medical field, for example, to examine turbulent flows .

Physical principle

Real-time MRT is based on very fast measurement sequences that allow image recording with a high temporal resolution. Typical examples of this are fast gradient echo sequences (e.g. the FLASH sequence), the TrueFISP technique or fast non-segmented fast / turbo spin echo methods. The fastest MRT technology to date combines a FLASH sequence with considerably under-sampled radial trajectories and an iterative reconstruction process that defines the image calculation as the solution of a nonlinear inverse problem with temporal regularization. In this way, a temporal resolution of 10 to 40 milliseconds per image is achieved. An important area of application for this technique is cardiac imaging.

Web links

Individual evidence

↑ Matt A. Bernstein, Kevin Franklin King, Xiaohong Joe Zhou: Handbook of MRI pulse sequences . Academic Press, 2004, ISBN 0-12-092861-2 , pp. 394 ( limited preview in Google Book search).
↑ ^a ^b Vinzenz Hombach (Ed.): Cardiovascular magnetic resonance tomography . 1st edition. Schattauer, 2009, ISBN 3-7945-2624-4 , p. 288 ( limited preview in Google Book search).
↑ ^a ^b Thomas C. Lauenstein (Ed.): Gastrointestinal MRT: Theory and Practice . 1st edition. ABW Wissenschaftsverlag, 2009, ISBN 3-936072-91-4 , p. 50, 55 ( limited preview in Google Book search).
↑ ^a ^b ^c S Zhang, M Uecker, D Voit, KD Merboldt, J Frahm, Real-time cardiovascular magnetic resonance at high temporal resolution: radial FLASH with nonlinear inverse reconstruction. J Cardiovasc Magn Reson 12, 39, (2010), doi : 10.1186 / 1532-429X-12-39 .
↑ M Uecker, S Zhang, D Voit, A Karaus, KD Merboldt, J Frahm, Real-time magnetic resonance imaging at a resolution of 20 ms, NMR in Biomedicine 23: 986-994 (2010), doi : 10.1002 / nbm. 1585 .

[1] Matt A. Bernstein, Kevin Franklin King, Xiaohong Joe Zhou: Handbook of MRI pulse sequences . Academic Press, 2004, ISBN 0-12-092861-2 , pp. 394 ( limited preview in Google Book search).

[Hombach2009-2] Vinzenz Hombach (Ed.): Cardiovascular magnetic resonance tomography . 1st edition. Schattauer, 2009, ISBN 3-7945-2624-4 , p. 288 ( limited preview in Google Book search).

[Lauenstein2009-3] Thomas C. Lauenstein (Ed.): Gastrointestinal MRT: Theory and Practice . 1st edition. ABW Wissenschaftsverlag, 2009, ISBN 3-936072-91-4 , p. 50, 55 ( limited preview in Google Book search).

[zhang-4] S Zhang, M Uecker, D Voit, KD Merboldt, J Frahm, Real-time cardiovascular magnetic resonance at high temporal resolution: radial FLASH with nonlinear inverse reconstruction. J Cardiovasc Magn Reson 12, 39, (2010), doi : 10.1186 / 1532-429X-12-39 .

[5] M Uecker, S Zhang, D Voit, A Karaus, KD Merboldt, J Frahm, Real-time magnetic resonance imaging at a resolution of 20 ms, NMR in Biomedicine 23: 986-994 (2010), doi : 10.1002 / nbm. 1585 .