Abstract: A method including receiving an initial dataset of data points and a sampled dataset including a sampling of data in a second dataset. Identified are a first number of subpopulations in the initial dataset and a second number of subpopulations in the sampled dataset corresponding to the first number of subpopulations. A measure of representativeness is identified using the first number of subpopulations in the initial dataset and the second number of subpopulations in the sampled dataset. A measure of coverage of the sampled dataset is identified relative to the initial dataset. An initial machine learning model is executed on the sampled dataset based on thresholds to generate a number of outputs corresponding to the subpopulations. A number of accuracies of the initial machine learning model are determined for the second number of subpopulations. The sampled dataset is remediated. The initial machine learning model is retrained.

Abstract: An MRI k-space data set is acquired using a series of shell k-space sampling trajectories of different radii. Off-resonance effects are reduced and fat-suppression can be improved by using a shorter TR for pulse sequences that sample at smaller radii. At larger radii sampling is repeated with the central axis of the shell sampling trajectory tilted such that the polar regions of shells acquired at the same radii are sampled by the other shell.

Abstract: An MRI k-space data set is acquired using a series of shell k-space sampling trajectories of different radii. Off-resonance effects are reduced and fat-suppression can be improved by using a shorter TR for pulse sequences that sample at smaller radii. At larger radii sampling is repeated with the central axis of the shell sampling trajectory tilted such that the polar regions of shells acquired at the same radii are sampled by the other shell.

Abstract: A 3D MRI image is acquired as a series of spherical shells of increasing radius. Each shell is sampled by one or more interleaved spiral sampling trajectories and to shorten the scan time one or more spiral sampling trajectories are skipped in the larger shells that sample the periphery of k-space. Motion correction of the acquired k-space data is accomplished by reconstructing tracking images from each of the shells and locating markers therein which indicate object movement from a reference position. The k-space data is corrected using this movement information.