Evaluation of 2D multiband EPI imaging for high-resolution, whole-brain, task-based fMRI studies at 3T: Sensitivity and slice leakage artifacts

摘要: Functional magnetic resonance imaging (fMRI) studies that require high-resolution whole-brain coverage have long scan times are primarily driven by the large number of thin slices acquired. Two-dimensional multiband echo-planar (EPI) sequences accelerate data acquisition along slice direction and therefore represent an attractive approach to such improving temporal resolution without sacrificing spatial resolution. In this work, a 2D EPI sequence was optimized for 1.5mm isotropic acquisitions at 3T with 10 healthy volunteers imaged while performing simultaneous visual motor tasks. The performance evaluated in terms BOLD sensitivity false-positive activation (MB) factors 1, 2, 4, 6, combined in-plane GRAPPA acceleration 2× (GRAPPA 2), two reconstruction approaches Slice-GRAPPA Split Slice-GRAPPA. Sensitivity results demonstrate significant gains signal-to-noise ratio (tSNR) t-score statistics MB 6 compared 1. factor optimal varied depending on anatomical location method. When using reconstruction, evidence due signal leakage between simultaneously excited seen one instance, 35 instances, 70 instances over ten respective accelerations 2×GRAPPA 4×GRAPPA 6×GRAPPA 2. use suppressed prevalence false positives significantly, 1 5 same factors. Imaging protocols 2 can be confidently used improve very low probability leakage. higher (MB 3 or 2) likely provide even greater but should carefully minimize possibility activations.