Novel Sampling Strategy for Abdominal Imaging with Incomplete Breathholds

Introduction:
Respiratory motion is a common source of artifacts in MRI, especially in abdominal imaging. Theycan be minimized by breath-holding during the acquisition. However, the ability of patients tocomply with predefined breathhold lengths varies greatly, often resulting in in-complete breathholds and thus motion artifacts. Previously, this problem has been addressed by using a center-out profile order, since respiratorymotion tends to produce less severe artifacts when it occurs duringthe acquisition of the k-space periphery [1]. However, an overestimation of theactual breathhold length still leads to artifacts. In this work, a different profileorder is proposed and explored, which supports the reconstruction ofimages from data acquired up to any point in time and thus the exclusion of data collected after the onset of respiratory motion. The amount of dataavailable for the reconstruction is unknown in advance, like in some approaches to imaging during free breathing [2]. The profile order is based on asegmented acquisition with global sampling density variation and local Poisson disk (PD) sampling [3], and it is compatible with compressedsensing (CS) and parallel imaging (PI) for accelerated scanning, as well as adaptable to target functions of the spatial resolution over time.