Accelerated Neuro MRA Using Compressed Sensing and Constrained Reconstruction

We have been developing acquisition and reconstruction methods that circumvent MRI shortcomings in speed and resolution to provide multi-dimensional physiological and anatomical information for neurovascular imaging. We have recognized that in order to achieve the required combinations of spatial and temporal resolution and signal-to-noise ratio we need to exploit the synergy of complementary advanced image acquisition and reconstruction techniques. Image estimation methods developed in our labs combine constrained reconstruction algorithms with non-Cartesian radial trajectories whose variable sampling density allows for both high quality extended scans and time-resolved imaging. We have already successfully developed the first generation of this technology known as the HYPR (HighlY constrained Projection Reconstruction) family of imaging techniques, delivering substantial acceleration to the acquisition of serially acquired images. This proposal suggests a next-generation of accelerated imaging technology for the comprehensive evaluation of vessel stenoses, aneurysms, and AVMs that will rival and surpass CT through the development of new image acquisition and reconstruction methods. These methods will utilize independent and symbiotic acceleration mechanisms of optimized radial trajectories, parallel imaging, and constrained reconstruction, including HYPR and advanced compressed sensing algorithms. These algorithms will also be supplied with data from novel highly accelerated acquisition methods: 1) a contrast-material-free inflow technique that eliminates the dispersion of a contrast-material bolus to provide superb arterial isolation, high resolution, and coverage; and 2) high quality time-averaged vascular image volumes to constrain reconstruction of time-resolved contrast-enhanced data. These methods will be evaluated in the treatment and tracking of AVMs, the evaluation of vascular stenoses and the evaluation of cerebral aneurysms. Successful completion would supplement the arsenal of tools used in stroke management as well.