Balanced steady-state free precession (bSSFP) imaging enables high scan efficiency in MRI, but differs from conventional sequences in terms of elevated sensitivity to main field inhomogeneity and nonstandard T 2 /T 1 -weighted tissue contrast. To address these limitations, multiple bSSFP images of the same anatomy are commonly acquired with a set of different RF phase-cycling increments. Joint processing of phasecycled acquisitions serves to mitigate sensitivity to field inhomogeneity. Recently phase-cycled bSSFP acquisitions were also leveraged to estimate relaxation parameters based on explicit signal models. While effective, these model-based methods often involve a large number of acquisitions (N ≈ 10-16), degrading scan efficiency. Here, we propose a new constrained ellipse fitting method (CELF) for parameter estimation with improved efficiency and accuracy in phase-cycled bSSFP MRI. CELF is based on the elliptical signal model framework for complex bSSFP signals; and it introduces geometrical constraints on ellipse properties to improve estimation efficiency, and dictionarybased identification to improve estimation accuracy. CELF generates maps of T 1 , T 2 , off-resonance and on-resonant bSSFP signal by employing a separate B 1 map to mitigate sensitivity to flip angle variations. Our results indicate that CELF can produce accurate off-resonance and bandingfree bSSFP maps with as few as N = 4 acquisitions, while estimation accuracy for relaxation parameters is notably limited by biases from microstructural sensitivity of bSSFP imaging.

Objective: Balanced steady‐state free precession (bSSFP) imaging suffers from banding artifacts in the presence of magnetic field inhomogeneity. The purpose of this study is to identify an efficient strategy to reconstruct banding‐free bSSFP images from multi‐coil multi‐acquisition datasets. Method: Previous techniques either assume that a naïve coil‐combination is performed a priori resulting in suboptimal artifact suppression, or that artifact suppression is performed for each coil separately at the expense of significant computational burden. Here we propose a tailored method that factorizes the estimation of coil and bSSFP sensitivity profiles for improved accuracy and/or speed. Results: In vivo experiments show that the proposed method outperforms naïve coil‐combination and coil‐by‐coil processing in terms of both reconstruction quality and time. Conclusion: The proposed method enables computationally efficient artifact suppression for phase‐cycled bSSFP imaging with modern coil arrays. Rapid imaging applications can efficiently benefit from the improved robustness of bSSFP imaging against field inhomogeneity.

The large magnetic susceptibility difference between metallic implants and surrounding tissues causes severe MRI artifacts that scale with the B0 field strength. At conventional field strengths, spin-echo based multispectral imaging is used to mitigate this artifact and produce diagnostic images. At lower field strengths, such as 0.55 T, other strategies may be feasible. Here, we investigate gradient-echo based sequences for imaging near metal at 0.55 T, which provide high SNR efficiency and different contrast.

Conventional MR image reconstruction relies on the assumption of perfectly linear gradient fields. However, the gradient fields contain spatially varying nonlinear components. We present a higher-order image reconstruction method that incorporates a theoretical model of gradient nonlinearity without any external field monitoring device. This approach utilizes the separability of Fourier encoding in Cartesian imaging and employs a low-rank approximation only to the higher-order readout encoding matrix, allowing a memory-efficient implementation suitable for large FOVs. Image distortions due to gradient nonlinearity were successfully mitigated by the proposed method using axial/sagittal/coronal 2D Cartesian datasets acquired on a prototype 0.55T MRI system.

The aim of this study is to specify the needs of Pilates instructors' educational needs. In this study which was designed as a case study, focus interviews were conducted with 26 participants whose 3 of them managers, 9 of them instructors and 14 of them members. Content analysis method was used in the analysis of qualitative data that was obtained from the interviews. In the interviews with participants, findings in five dimensions were obtained in Pilates educational training as basic knowledge and skills, communication skills, practice knowledge and skills, environment regulation knowledge and skills and measurement knowledge and skills. Participants in the basic knowledge and skills dimension indicated that Pilates instructors need to obtain basic sports, health and anatomic knowledge. In the practice knowledge and skills dimension, according to the participants, Pilates trainers should have knowledge and skills such as creating group levels, making corrections and giving feedback. According to participants, Pilates instructors should also be able to use communication skills effectively. In the Pilates training, especially the spaciousness of the environment, the presence of mirrors and music was indicated essential by the participants. For the measurement dimension, participants indicated that Pilates trainers should be able to make body measurements.