Motion robust MR-ARFI using timeseries single-shot spiral acquisition

Motivation: 2DFT MR-ARFI methods used to map ultrasound beam profiles can fail with small amounts of head motion because the signal is based on phase shifts from um-sized Acoustic Radiation Force displacement of tissue. Goal(s): To demonstrate that a single-shot timeseries method is more robust to bulk motion. Approach: Employing an efficient spiral redout trajectory, we compared the two methods’ ARFI images in a tissue-mimicking phantom undergoing controlled random translations. Results: The timeseries method demonstrated good quality tissue translation maps, while the 2DFT method failed with motions as small as ~50 microns RMS. Impact: Our single-shot method may allow routine use of MR-ARFI in humans for guiding US neuromodulation and US-based ablative therapy.