Abstract:
Magnetic resonance imaging (MRI) is a clinical imaging modality with a wide range of uses from structural imaging of soft tissues to dynamic imaging of brain function. In many MRI applications, only a portion of the signal-generating tissue (water protons, or 'spins') is of interest. For example, in cardiac or brainstem imaging the region-of-interest occupies a relatively small part of the full field-of-view, and in perfusion MRI we wish to limit the signal to slow-moving blood in the small arteries and capillaries. Unfortunately, in conventional MRI one has limited ability to selectively excite spins based on their spatial location or velocity, which can result in unnecessarily long scan times or inaccurate perfusion estimates. In this talk I will discuss our work toward designing ‘shaped’ radiofrequency (RF) pulses for improved 3D spatial selection, and present possible future directions for designing improved velocity-selective RF pulses.

Bio:
Jon-Fredrik Nielsen, PhD, is Research Associate Professor of Radiology at U of Michigan, specializing in MRI protocol design and open-source MRI programming with applications in functional and quantitative MRI.