Human hippocampal subfields in young adults at 7.0 T: feasibility of imaging.

PURPOSE: To establish an imaging approach to visualize the 100-microm-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 METHODS: The 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-microm in-plane resolution (0.05-mm(3) pixels) in coronal and sagittal slabs (17 sections at 1 mm thick) over the hippocampus in 14 minutes. The entire study took 45 minutes.
RESULTS: The DGCL was consistently visible in all 10 enrolled subjects. All larger subfields were visible in excellent detail and contrast in every subject.
CONCLUSION: The spatial resolution and tissue contrast at high field strength (7.0 T) MR imaging can be used to consistently reveal hippocampal morphology down to 100-microm subfields within a clinically acceptable imaging duration. This imaging technique might be used to detect cellular disarray and degenerative changes in this sensitive circuit earlier than at 1.5 T or even 3.0 T. (c) RSNA, 2010.