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Abstract #2088

Comparison of Thermal and Physiological Noise Amplification in Accelerated and Segmented EPI Acquisitions

Christina Triantafyllou1, 2, Jonathan R. Polimeni3, Jennifer A. McNab3, Thomas Witzel3, Lawrence L. Wald3, 4

1A.A. Martinos Imaging Center, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, United States; 2A.A. Martinos Center for Biomedical Imaging, Department of Radiology, , MGH, Charlestown, MA, United States; 3A.A. Martinos Center for Biomedical Imaging, Department of Radiology,, MGH, Charlestown, MA, United States; 4Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States

In this study, we compare two different acquisitions; Accelerated (GRAPPA) single-shot and non-accelerated mutli-shot EPI with matched effective echo spacing. Our findings demonstrate that in both thermal and physiological noise dominated acquisitions, when the temporal sampling interval is matched, by temporally smoothing the single-shot time-series, the single-shot accelerated time-series result in higher tSNR. But if the fixed duration scan can afford reduced temporal resolution (sampling interval not matched), then the slower multi-shot strategy provides slightly higher tSNR than the distortion matched single-shot acquisition.

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Keywords

accelerated acceleration achieve achieved acquisition acquisitions additionally advances allowing amongst amplification apparent array averaging biomedical block blurring bold brain coil coils combined consistent constant content correction correlated correlation correlations cortical course created decreased degree detection deviation distortion distortions divided division dominate dominated drift duration effective either enabled equal equivalent evaluated even every exist experiment exploration faster field filtered findings fixed fluctuations fold full function functional generated gradient gray head health highly indicate indicating instability institute interval isotropic kept likely limit magnetization maps match matched matching metric millimeter minute motion noise original parallel physiological pixel potentially preferable preserve product protocols radiology readout receive recent reduce reduced repetition representative resolution resolutions respectively retaining root runs sampled sampling scheme sciences segmented segments series shorter shot shots since slightly slower smoothing spacing spatial squares steady strategy strengths subjects suggest susceptibility system technological technology temporal temporally thermal though trio truncated usually variation varied version whereas yield