An application which greatly benefits from Ultra High Field (UHF) MRI is Blood Oxygenation Level Dependent (BOLD) fMRI. The increased susceptibility effects at UHF translate into a greater observable BOLD signal change and therefore improved fMRI experiments [1], as demonstrated in rat forepaw stimulation study at 15.2 Tesla, where an over 11% BOLD response was seen [2].
Functional MRI is used to study functional connectivity to further understand brain function in health and disease [3]. Using the high sensitivity provided by UHF, high resolution fMRI preclinical experiments thus become feasible [4]. Forepaw somatosensory stimulation, for example, only commonly shows BOLD response in S1FL. A recent study at 9.4 T and 15.2 T, however, detected only S1FL response at 9.4 T, but S2 and thalamus as well as S1FL at 15.2 T [5]. Functional sensitivity will additionally benefit from UHF in situations where thermal noise is dominant, as it is directly dependent on sensitivity and indirectly dependent on temporal noise [2]. This is the case for high resolution studies which are enabled at UHF [6].