MB-SWIFT functional MRI during deep brain stimulation in rats

- MB-SWIFT is a virtually zero-TE pulse sequence and it can achieve high bandwidths.
- It is shown to produce functional contrast during deep brain stimulation in rats.
- Susceptibility artefact surrounding the electrode is minimized.
- The extent and amplitude of the functional response are similar to that of SE-EPI.
- The functional contrast is related to inflow of blood.

Recently introduced 3D radial MRI pulse sequence entitled Multi-Band SWeep Imaging with Fourier Transformation (MB-SWIFT) having virtually zero acquisition delay was used to obtain functional MRI (fMRI) contrast in rat's brain at 9.4 T during deep brain stimulation (DBS). The results demonstrate that MB-SWIFT allows functional images free of susceptibility artifacts, and provides an excellent fMRI activation contrast in the brain. Flip angle dependence of the MB-SWIFT fMRI signal and elimination of the fMRI contrast while using saturation bands, indicate a blood flow origin of the observed fMRI contrast. MB-SWIFT fMRI modality permits activation studies in the close proximity to an implanted lead, which is not possible to achieve with conventionally used gradient echo and spin echo - echo planar imaging fMRI techniques. We conclude that MB-SWIFT fMRI is a powerful imaging modality for investigations of functional responses during DBS.

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