TY - JOUR
T1 - Transceive phase mapping using the PLANET method and its application for conductivity mapping in the brain
AU - Gavazzi, Soraya
AU - Shcherbakova, Yulia
AU - Bartels, Lambertus W.
AU - Stalpers, Lukas J. A.
AU - Lagendijk, Jan J. W.
AU - Crezee, Hans
AU - van den Berg, Cornelis A. T.
AU - van Lier, Astrid L. H. M. W.
PY - 2020/2/1
Y1 - 2020/2/1
N2 - Purpose: To demonstrate feasibility of transceive phase mapping with the PLANET method and its application for conductivity reconstruction in the brain. Methods: Accuracy and precision of transceive phase (ϕ±) estimation with PLANET, an ellipse fitting approach to phase-cycled balanced steady-state free precession (bSSFP) data, were assessed with simulations and measurements and compared to standard bSSFP. Measurements were conducted on a homogeneous phantom and in the brain of healthy volunteers at 3 tesla. Conductivity maps were reconstructed with Helmholtz-based electrical properties tomography. In measurements, PLANET was also compared to a reference technique for transceive phase mapping, i.e., spin echo. Results: Accuracy and precision of ϕ± estimated with PLANET depended on the chosen flip angle and TR. PLANET-based ϕ± was less sensitive to perturbations induced by off-resonance effects and partial volume (e.g., white matter + myelin) than bSSFP-based ϕ±. For flip angle = 25° and TR = 4.6 ms, PLANET showed an accuracy comparable to that of reference spin echo but a higher precision than bSSFP and spin echo (factor of 2 and 3, respectively). The acquisition time for PLANET was ~5 min; 2 min faster than spin echo and 8 times slower than bSSFP. However, PLANET simultaneously reconstructed T1, T2, B0 maps besides mapping ϕ±. In the phantom, PLANET-based conductivity matched the true value and had the smallest spread of the three methods. In vivo, PLANET-based conductivity was similar to spin echo-based conductivity. Conclusion: Provided that appropriate sequence parameters are used, PLANET delivers accurate and precise ϕ± maps, which can be used to reconstruct brain tissue conductivity while simultaneously recovering T1, T2, and B0 maps.
AB - Purpose: To demonstrate feasibility of transceive phase mapping with the PLANET method and its application for conductivity reconstruction in the brain. Methods: Accuracy and precision of transceive phase (ϕ±) estimation with PLANET, an ellipse fitting approach to phase-cycled balanced steady-state free precession (bSSFP) data, were assessed with simulations and measurements and compared to standard bSSFP. Measurements were conducted on a homogeneous phantom and in the brain of healthy volunteers at 3 tesla. Conductivity maps were reconstructed with Helmholtz-based electrical properties tomography. In measurements, PLANET was also compared to a reference technique for transceive phase mapping, i.e., spin echo. Results: Accuracy and precision of ϕ± estimated with PLANET depended on the chosen flip angle and TR. PLANET-based ϕ± was less sensitive to perturbations induced by off-resonance effects and partial volume (e.g., white matter + myelin) than bSSFP-based ϕ±. For flip angle = 25° and TR = 4.6 ms, PLANET showed an accuracy comparable to that of reference spin echo but a higher precision than bSSFP and spin echo (factor of 2 and 3, respectively). The acquisition time for PLANET was ~5 min; 2 min faster than spin echo and 8 times slower than bSSFP. However, PLANET simultaneously reconstructed T1, T2, B0 maps besides mapping ϕ±. In the phantom, PLANET-based conductivity matched the true value and had the smallest spread of the three methods. In vivo, PLANET-based conductivity was similar to spin echo-based conductivity. Conclusion: Provided that appropriate sequence parameters are used, PLANET delivers accurate and precise ϕ± maps, which can be used to reconstruct brain tissue conductivity while simultaneously recovering T1, T2, and B0 maps.
KW - accuracy
KW - conductivity mapping
KW - ellipse fitting
KW - phase-cycled bSSFP
KW - precision
KW - transceive phase mapping
UR - http://www.scopus.com/inward/record.url?scp=85071735357&partnerID=8YFLogxK
U2 - https://doi.org/10.1002/mrm.27958
DO - https://doi.org/10.1002/mrm.27958
M3 - Article
C2 - 31483520
SN - 0740-3194
VL - 83
SP - 590
EP - 607
JO - Magnetic resonance in medicine
JF - Magnetic resonance in medicine
IS - 2
ER -