Functional Imaging by I0‐ and T2* ‐parameter mapping using multi‐image EPI

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Abstract
A new functional imaging method has been developed and used to measure T2*‐ and initial intensity (I0)‐parameter maps of multiple slices during activation of the cortex with high temporal resolution. Multiple echo‐planar images (EPls) are read out after a single excitation of the spin system, leading to several images with increasing effective echo times. Changes induced by primary visual stimulation in T2* and I0 were measured in eight subjects. Although stimulation‐induced increases in I0 only occurred at short repetition times, T2* increased from 57.3 to 60.9 ms on average. The method combines the high stability of a single shot EPI experiment with the high information content of a multiecho acquisition. In addition, stimulation‐induced changes in inflow can be easily separated from true blood oxygenation level dependent (BOLD) signal changes.