Human Hippocampal Subfields in Young Adults at 7.0 T: Feasibility of Imaging

Abstract

The combination of 7.0-T field strength, an advanced coil, field shimming, a high-count receive coil array, and heavy T2*-weighted contrast was shown to consistently depict hippocampal subfields down to 100-μm spatial resolution within a clinically acceptable protocol duration. PurposeTo establish an imaging approach to visualize the 100-μm-thick hippocampal neuron-generating dentate granule cell layer (DGCL) consistently within a clinically feasible magnetic resonance (MR) imaging duration and to assess its sensitivity by quantifying the likelihood that it will be detected in healthy young adults.Materials and MethodsThe study was HIPAA compliant and institutional review board approved. All subjects provided written informed consent. Ten healthy volunteers (five male subjects, five female subjects; mean age, 26 years ± 6 [standard deviation]) were imaged at 7.0 T by using a 24-element head coil array with three-dimensional T1-weighted MR imaging for anatomic reference, followed by T2*-weighted gradient-echo (echo time, 25 msec; repetition time, 944 msec) imaging at 232-μm in-plane resolution (0.05-mm3 pixels) in coronal and sagittal slabs (17 sections at 1 mm thick) over the hippocampus in 14 minutes. The entire study took 45 minutes.ResultsThe DGCL was consistently visible in ...