Thomas Benkert1, Philipp Ehses2, Martin Blaimer3, Peter M Jakob4, Felix A Breuer3. 1. Research Center Magnetic Resonance Bavaria (MRB), Würzburg, Germany. Electronic address: benkert@mr-bavaria.de. 2. Department of Neuroimaging, University of Tübingen, Tübingen, Germany; High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany. 3. Research Center Magnetic Resonance Bavaria (MRB), Würzburg, Germany. 4. Research Center Magnetic Resonance Bavaria (MRB), Würzburg, Germany; Department of Experimental Physics 5, Universität Würzburg, Würzburg, Germany.
Abstract
AIMS: Dynamically phase-cycled radial balanced steady-state free precession (DYPR-SSFP) is a method for efficient banding artifact removal in bSSFP imaging. Based on a varying radiofrequency (RF) phase-increment in combination with a radial trajectory, DYPR-SSFP allows obtaining a banding-free image out of a single acquired k-space. The purpose of this work is to present an extension of this technique, enabling fast three-dimensional isotropic banding-free bSSFP imaging. METHODS: While banding artifact removal with DYPR-SSFP relies on the applied dynamic phase-cycle, this aspect can lead to artifacts, at least when the number of acquired projections lies below a certain limit. However, by using a 3D radial trajectory with quasi-random view ordering for image acquisition, this problem is intrinsically solved, enabling 3D DYPR-SSFP imaging at or even below the Nyquist criterion. The approach is validated for brain and knee imaging at 3 Tesla. RESULTS: Volumetric, banding-free images were obtained in clinically acceptable scan times with an isotropic resolution up to 0.56mm. CONCLUSION: The combination of DYPR-SSFP with a 3D radial trajectory allows banding-free isotropic volumetric bSSFP imaging with no expense of scan time. Therefore, this is a promising candidate for clinical applications such as imaging of cranial nerves or articular cartilage.
AIMS: Dynamically phase-cycled radial balanced steady-state free precession (DYPR-SSFP) is a method for efficient banding artifact removal in bSSFP imaging. Based on a varying radiofrequency (RF) phase-increment in combination with a radial trajectory, DYPR-SSFP allows obtaining a banding-free image out of a single acquired k-space. The purpose of this work is to present an extension of this technique, enabling fast three-dimensional isotropic banding-free bSSFP imaging. METHODS: While banding artifact removal with DYPR-SSFP relies on the applied dynamic phase-cycle, this aspect can lead to artifacts, at least when the number of acquired projections lies below a certain limit. However, by using a 3D radial trajectory with quasi-random view ordering for image acquisition, this problem is intrinsically solved, enabling 3D DYPR-SSFP imaging at or even below the Nyquist criterion. The approach is validated for brain and knee imaging at 3 Tesla. RESULTS: Volumetric, banding-free images were obtained in clinically acceptable scan times with an isotropic resolution up to 0.56mm. CONCLUSION: The combination of DYPR-SSFP with a 3D radial trajectory allows banding-free isotropic volumetric bSSFP imaging with no expense of scan time. Therefore, this is a promising candidate for clinical applications such as imaging of cranial nerves or articular cartilage.
Authors: Zhitao Li; Zhiyang Fu; Mahesh Keerthivasan; Ali Bilgin; Kevin Johnson; Jean-Philippe Galons; Srinivasan Vedantham; Diego R Martin; Maria I Altbach Journal: Magn Reson Imaging Date: 2021-03-17 Impact factor: 3.130