Robust imaging of hippocampal inner structure at 7T: in vivo acquisition protocol and methodological choices

TL;DR

This study develops a motion-robust multi-slab MRI protocol at 7T for detailed in vivo imaging of the hippocampal inner structure, balancing image quality and acquisition time, and demonstrating high success rates in data quality across subjects.

Contribution

The paper introduces a novel multi-slab acquisition and registration method that improves robustness and reduces scan time for high-resolution hippocampal imaging at 7T.

Findings

Multi-slab registration achieved 96% high-quality datasets.

T2-weighted interleaved slabs proved robust against motion artifacts.

The protocol enables detailed analysis of hippocampal inner structure.

Abstract

OBJECTIVE:Motion-robust multi-slab imaging of hippocampal inner structure in vivo at 7T.MATERIALS AND METHODS:Motion is a crucial issue for ultra-high resolution imaging, such as can be achieved with 7T MRI. An acquisition protocol was designed for imaging hippocampal inner structure at 7T. It relies on a compromise between anatomical details visibility and robustness to motion. In order to reduce acquisition time and motion artifacts, the full slab covering the hippocampus was split into separate slabs with lower acquisition time. A robust registration approach was implemented to combine the acquired slabs within a final 3D-consistent high-resolution slab covering the whole hippocampus. Evaluation was performed on 50 subjects overall, made of three groups of subjects acquired using three acquisition settings; it focused on three issues: visibility of hippocampal inner structure, robustness to motion artifacts and registration procedure performance.RESULTS:Overall, T2-weighted acquisitions with interleaved slabs proved robust. Multi-slab registration yielded high quality datasets in 96 % of the subjects, thus compatible with further analyses of hippocampal inner structure.CONCLUSION:Multi-slab acquisition and registration setting is efficient for reducing acquisition time and consequently motion artifacts for ultra-high resolution imaging of the inner structure of the hippocampus.