Ultra-high-field (7T) MRI enables high-resolution brain imaging but also exacerbates physiological artifacts and acoustic noise. In this talk, I will present two approaches that exploit timing to improve image quality and acquisition performance. The first project addresses physiological fluctuations in rapid 3D MRI. We developed a semi-randomized phase-encoding strategy that suppresses artifacts from respiration, cardiac pulsation, and eye movements by exploiting their characteristic temporal frequencies. The method was demonstrated in human brain MRI at both 7T and 11.7T, including susceptibility-weighted imaging (SWI), quantitative T2 mapping, and MR angiography. The second project focuses on echo-planar imaging (EPI), the workhorse of functional MRI (fMRI), where the fast acquisitions produce high acoustic noise, particularly at ultra-high field. We show that subtle changes in gradient timing can substantially reduce acoustic energy. Timing optimization can also mitigate imaging ghosting, complementing the reduction in acoustic noise to enable quieter, more robust fMRI. Together, these projects demonstrate that careful timing can enable high-quality, high-resolution neuroimaging while improving patient comfort and extending hardware lifetime.
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