Petra Schmalbrock PhD, Presenter: Nothing to Disclose

Keith M Vogt BS, Abstract Co-Author: Nothing to Disclose

Regina Maria Koch MD, Abstract Co-Author: Nothing to Disclose

Steffen Sammet MD, PhD, Abstract Co-Author: Nothing to Disclose

John Duraj BA, Abstract Co-Author: Nothing to Disclose

Michael Vinzenz Knopp MD, PhD, Abstract Co-Author: Nothing to Disclose

To assess the feasibility of language task fMRI for evaluating Broca’s area at ultra-high field (7T), and to relate findings with 3T in an intra-individual comparison.

Three healthy subjects (ages 25-51y) were instructed to alternate between rest and thinking of words starting with a given letter. This task is known to robustly activate Broca’s area. Dynamic fMRI data were acquired (10 rest, 10 task, total 70 time points) using 8-channels SENSE array head coils at 3T and 7T. EPI images were acquired with a SENSE reduction factor of 2 and 3 at 3T and 7T, respectively. This minimized image distortion that are due to echo trains longer than T2*, yet maintains a reasonable BOLD contrast-to-noise ratio. Other parameters were TR/TE=3000/35ms at 3T, TR/TE 3600/25ms at 7T, FOV 23x23cm matrix 80x80, 25 slices of 4mm covering the whole brain. Statistical analysis was carried out using FSL.

Broca’s area was activated in all subjects at 3T and 7T. Using fairly large SENSE reduction factors minimized geometric distortion and allowed for whole brain assessment at ultra-high field (7T). However, there was some variability in the statistical measures of the data. This may be because Broca’s area is fairly close to air-filled sinus spaces causing significant magnetic susceptibility gradients leading to image distortion.

This feasibility study demonstrated that language task fMRI for assessment of Broca’s area is feasible at Ultra High Field (7T). Further acquisition optimization will improve quantitative reliability of the fMRI data at ultra high field.

Ultrahigh-field fMRI is more sensitive and specific for brain microcirculation and can be used for fundamental neuroscience research and clinical applications such as pre-surgical evaluations.

Schmalbrock, P, Vogt, K, Koch, R, Sammet, S, Duraj, J, Knopp, M, Comparison of Language Task fMRI at 3T and 7T.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4429663.html