2025/06/02 by Peter Lally, Yifei Jin, Zimu Huo +5 · 1 voice
Medicine · #Advanced MRI Techniques and Applications #Advanced Neuroimaging Techniques and Applications #Ultrasound Imaging and Elastography
paper · pdf · doi:10.1002/mrm.30590
openalex publication_date 2025/06/02 · openalex created_date 2025/06/04 · openalex updated_date 2026/07/28
Abstract Purpose Multi‐echo gradient echo imaging is useful for a range of applications including relaxometry, susceptibility mapping, and quantifying relative proportions of fat and water. This relies primarily on long‐TR multi‐echo gradient echo sequences (FLASH), which by design isolate one signal component (i.e., echo) at a time per readout. In this work, we propose an alternative strategy that simultaneously measures all signal components at once in every readout event with an N‐periodic SSFP sequence. Essentially, we Fourier encode the signals into an “F‐k space” similar to the “TE‐k space” of a multi‐echo gradient echo acquisition. This enables an efficient, short‐TR relaxometry experiment where signals benefit from averaging effects over multiple excitations. Theory and Methods In the presented approach, multiple echoes are recorded simultaneously and separated by their differing phase evolution over multiple TRs. At low flip angles the relative echo amplitudes and phases are equivalent to those acquired sequentially from a multi‐echo FLASH, in terms of both T 2 * weighting and spatial phase distributions. The two approaches were compared for the example of R 2 * relaxometry in a phantom and in human volunteers. Results The proposed approach shows close agreement in R 2 * estimation with multi‐echo FLASH, with the advantage of more rapid temporal sampling. Conclusion The proposed approach is a promising alternative to other relaxometry approaches, by measuring signals from multiple echo pathways simultaneously and separating them based on a simple analytical model.