Effects of RF pulse profile and intra-voxel phase dispersion on MR fingerprinting with balanced SSFP readout
Journal
Magnetic Resonance Imaging
Journal Volume
41
Pages
27005
Date Issued
2017
Author(s)
Abstract
Purpose To investigate possible errors in T1 and T2 quantification via MR fingerprinting with balanced steady-state free precession readout in the presence of intra-voxel phase dispersion and RF pulse profile imperfections, using computer simulations based on Bloch equations. Materials and methods A pulse sequence with TR changing in a Perlin noise pattern and a nearly sinusoidal pattern of flip angle following an initial 180-degree inversion pulse was employed. Gaussian distributions of off-resonance frequency were assumed for intra-voxel phase dispersion effects. Slice profiles of sinc-shaped RF pulses were computed to investigate flip angle profile influences. Following identification of the best fit between the acquisition signals and those established in the dictionary based on known parameters, estimation errors were reported. In vivo experiments were performed at 3 T to examine the results. Results Slight intra-voxel phase dispersion with standard deviations from 1 to 3 Hz resulted in prominent T2 under-estimations, particularly at large T2 values. T1 and off-resonance frequencies were relatively unaffected. Slice profile imperfections led to under-estimations of T1, which became greater as regional off-resonance frequencies increased, but could be corrected by including slice profile effects in the dictionary. Results from brain imaging experiments in vivo agreed with the simulation results qualitatively. Conclusion MR fingerprinting using balanced SSFP readout in the presence of intra-voxel phase dispersion and imperfect slice profile leads to inaccuracies in quantitative estimations of the relaxation times. ? 2017 Elsevier Inc.
Subjects
Intra-voxel phase dispersion; MR fingerprinting; Quantitative relaxation mapping; RF pulse; Slice profile
SDGs
Other Subjects
adult; Article; computer simulation; human; image analysis; in vivo study; intra voxel phase dispersion; magnetic resonance fingerprinting; measurement accuracy; neuroimaging; normal human; nuclear magnetic resonance; nuclear magnetic resonance scanner; priority journal; radiofrequency pulse; radiofrequency radiation; radiological parameters; relaxation time; steady state free precession readout; algorithm; automated pattern recognition; brain; diagnostic imaging; heart rate; image processing; imaging phantom; nuclear magnetic resonance imaging; pathophysiology; procedures; reproducibility; signal processing; Adult; Algorithms; Brain; Computer Simulation; Healthy Volunteers; Heart Rate; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Pattern Recognition, Automated; Phantoms, Imaging; Radio Waves; Reproducibility of Results; Signal Processing, Computer-Assisted
Type
journal article