Modelling Magnetization Transfer Considering Spin-Locking Effects


Purpose: Recently it was demonstrated that spin-locking (SL) effects can manifest as pseudo magnetization transfer (MT). To our best knowledge the MT models proposed so far cannot distinguish between saturation effects caused by the MT preparation pulses and SL phenomena. Therefore a new MT model is proposed. Materials and Methods: A binary spin-bath model for magnetization transfer was extended in that sense that SL effects are considered. The new modified spin bath model was tested for a phantom with different agar concentrates (2%, 4%, 8%) and a MnCl2 (0.3 mM) solution. Results: The mean fitting error is 3.2 times lower for the modified model compared to the original model. Especially the parameter F for the fractional part of the bounded proton pool describes the situation for the MnCl2 (F = 0) better than the original model (F = 0.004). Conclusion: The proposed mathematical modifications of the binary spin-bath model considering SL seem to be a step in the right direction in that sense that the effects associated with SL are not interpreted as magnetization transfer.

Share and Cite:

Kiefer, C. (2014) Modelling Magnetization Transfer Considering Spin-Locking Effects. Open Journal of Medical Imaging, 4, 199-204. doi: 10.4236/ojmi.2014.44027.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Pike, G.B. (1996) Pulsed Magnetization Transfer Contrast in Gradient Echo Imaging: A Two Pool Analytic Description of Signal Response. Magnetic Resonance in Medicine, 36, 95-103.
[2] Sled, J.G. and Pike, G.B. (2000) Quantitative Interpretation of Magnetization Transfer in Spoiled Gradient Echo MRI Sequences. Journal of Magnetic Resonance, 145, 24-36.
[3] Sled, J.G. and Pike, G.B. (2001) Quantitative Imaging of Magnetization Transfer Exchange and Relaxation Properties in Vivo Using MRI. Magnetic Resonance in Medicine, 46, 923-931.
[4] Kiefer, C., Brockhaus, L., Cattapan-Ludewig, K., Ballinari, P., Burren, Y., Schroth, G. and Wiest, R. (2009) Multiparametric Classification of Alzheimer’s Disease and Mild Cognitive Impairment: The Impact of Quantitative Magnetization Transfer MR Imaging. NeuroImage, 48, 657-667.
[5] Stanisz, G.J., Yoon, R.S., Joy, M.L.G. and Henkelman, R.M. (2002) Why Does MTR Change with Neuronal Depolarization? Magnetic Resonance in Medicine, 47, 472-475.
[6] Ulmer, J.L., Mathews, V.P., Hamilton, C.A., Elster, A.D. and Moran, P.R. (1996) Magnetization Transfer or Spin- Lock? An Investigation of Off-Resonance Saturation Pulse Imaging with Varying Frequency Offsets. AJNR—American Journal of Neuroradiology, 17, 805-819.
[7] Kiefer, C. (2014) Simultaneous Echo Refocused Magnetization Transfer Imaging. Open Journal of Medical Imaging, 4, 154-158.

Copyright © 2021 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.