BMART-Enabled Field-Map Combination of Projection-Reconstruction Phase-Cycled SSFP Cardiac Cine for Banding and Flow-Artifact Reduction

TL;DR

This paper introduces a novel method combining BMART and a projection-reconstruction trajectory to produce banding-free, flow-artifact-reduced cardiac cine images in a short breath-hold, improving image quality.

Contribution

It develops a field-map-based phase-cycle combination method using BMART and PR trajectory for enhanced cardiac cine imaging.

Findings

Effective reduction of banding artifacts in cardiac cine images.

Improved visualization of blood pools with fewer flow artifacts.

Shortened scan time for high-quality cardiac imaging.

Abstract

Purpose: To develop a method for banding-free bSSFP cardiac cine with substantially reduced flow artifacts. Methods: A projection-reconstruction (PR) trajectory is proposed for a frequency-modulated cine sequence, facilitating reconstruction of three phase cycles and a field-map time series from a short, breath-held scan. Data is also acquired during the gradient rewinders to enable generation of field maps using BMART, B$_0$ mapping using rewinding trajectories, where the rewind data forms the second TE image for calculating the field map. A field-map-based combination method is developed which weights the phase-cycle component images to include only passband signal in the final cine images, and exclude stopband and near-band flow artifacts. Results: The weights derived from the BMART-generated field maps mask out banding and near-band flow artifacts in and around the heart. Therefore, the field-map-based phase-cycle combination, which is facilitated by the PR acquisition with BMART, results in more homogeneous blood pools and reduced hyperintense regions than root-sum-of-squares. Conclusion: With the proposed techniques, using a non-Cartesian trajectory for a frequency-modulated cine sequence enables flow-artifact-reduced banding-free cardiac imaging within a short breath-hold.