Jens Frahm PhD, Presenter: Nothing to Disclose

Shuo Zhang MS, Abstract Co-Author: Nothing to Disclose

To develop a generic solution for real-time MRI with excellent image quality, different contrasts, and high frame rates.

The approach is based on a combination of fast low-angle shot (FLASH) MRI sequences with radial data sampling and view sharing of successive acquisitions. Gridding reconstructions provide images free from streaking or motion artifacts and with a flexible trade-off between spatial and temporal resolution. Immediate image reconstruction and online display is accomplished with the use of an unmodified 3 T MRI system. For receive coils with a large number of elements this process is supported by a user-selectable channel compression that is based on a principal component analysis and performed during initial preparation scans. Available contrasts include spin density- and T1-weighted images (spoiled FLASH) or T1/T2-weighted images (refocused or fully balanced FLASH) as well as in-phase and opposed-phase acquisitions.

In healthy volunteers, real-time radial FLASH MRI visualized continuous movements of the temporomandibular joint and knee at 3 frames per second and 0.75 mm in-plane resolution. Cardiac functions were monitored at 20 to 30 frames per second during free breathing and without ECG synchronization at 1.5 to 2.0 mm in-plane resolution. All images were free from motion artifacts offering a wide range of choices trading temporal versus spatial resolution.

Real-time radial FLASH MRI emerges as a simple, robust, and versatile tool for a large range of clinical applications. It is immediately usable on existing MRI systems without any modification of the hardware.

Real-time radial FLASH MRI allows for functional assessments of joints and the heart during free breathing and will facilitate interventional MRI due to its absence of susceptibility artifacts.

Frahm, J, Zhang, S, Real-Time MRI Using Radial FLASH Sequences.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8005098.html