High‐resolution 7T MRI of the human hippocampus in vivo

Abstract

Purpose To describe an initial experience imaging the human hippocampus in vivo using a 7T magnetic resonance (MR) scanner and a protocol developed for very high field neuroimaging. Materials and Methods Six normal subjects were scanned on a 7T whole body MR scanner equipped with a 16‐channel head coil. Sequences included a full field of view T1‐weighted 3D turbo field echo (T1W 3D TFE: time of acquisition (TA) = 08:58), T2*‐weighted 2D fast field echo (T2*W 2D FFE: TA = 05:20), and susceptibility‐weighted imaging (SWI: TA = 04:20). SWI data were postprocessed using a minimum intensity projection (minIP) algorithm. Total imaging time was 23 minutes. Results T1W 3D TFE images with 700 μm isotropic voxels provided excellent anatomic depiction of macroscopic hippocampal structures. T2*W 2D FFE images with 0.5 mm in‐plane resolution and 2.5 mm slice thickness provided clear discrimination of the Cornu Ammonis and the compilation of adjacent sublayers of the hippocampus. SWI images (0.5 mm in‐plane resolution, 1.0 mm slice thickness) delineated microvenous anatomy of the hippocampus. Conclusion In vivo 7T MR imaging can take advantage of higher signal‐to‐noise and novel contrast mechanisms to provide increased conspicuity of hippocampal anatomy. J. Magn. Reson. Imaging 2008;28:1266–1272.