This work describes our first efforts to implement SWIFT (SWeep Imaging with Fourier Transformation) in continuous mode for imaging and spectroscopy. We connected a standard quadrature hybrid with a quad coil and acquired NMR signal during continuous radiofrequency excitation. We utilized a chirped radiofrequency pulse to minimize the instantaneous radiofrequency field during excitation of the spin system for the target flip angle and bandwidth. Due to the complete absence of "dead time", continuous SWIFT has the potential to extend applications of MRI and spectroscopy in studies of spin systems having extremely fast relaxation or broad chemical shift distributions beyond the range of existing MRI sequences.
Bibliographical noteFunding Information:
This research was supported by NIH P41 RR008079, S10 RR023730, S10 RR027290 RR008079, R21 CA139688 Grants and the WM Keck Foundation. We thank Drs. Ryan Chamberlain and Peter Andersen for useful discussions and Drs. Jutta Ellermann, Wen Ling, and Elizabeth Arendt for the opportunity to use the TKA sample in this study. In addition, we thank Dr. Rajesh Venkataraman for developing the gridding code.
- Continuous wave
- Sweep Imaging