Characterization of normal appearing brain structures using high-resolution quantitative magnetization transfer steady-state free precession imaging

Compared to standard spoiled gradient echo (SPGR)-methods, balanced steady-state free precession (bSSFP) provides quantitative magnetization transfer (qMT) images with increased resolution and high signal-to-noise ratio (SNR) in clinically feasible acquisition times. The aim of this study was to acquire 3D high-resolution qMT-data to create standardized qMT-values of many single brain structures that might serve as a baseline for the future characterization of pathologies of the brain. QMT parameters, such as the fractional pool size (F), exchange rate (kf) and relaxation times of the free pool (T1, T2) were assessed in a total of 12 white matter (WM) and 11 grey matter (GM) structures in 12 healthy volunteers with MT-sensitized bSSFP. Our results were compared with qMT-data from previous studies obtained with SPGR-methods using MT-sensitizing preparation pulses with significantly lower resolution. In general, qMT-values were in good accordance with prior studies. As expected, higher F and kf and lower relaxation times were observed in WM as compared to GM structures. However, many significant differences were observed within WM and GM regions and also between different regions of the same structure like in the internal capsule where the posterior limb showed significant higher kf than the anterior limb. Significant differences for all parameters were observed between subjects. In contrast to previous studies, bSSFP allowed assessment of even small brain structures due to its high resolution. The observed differences from previous studies can partly be explained by the reduced partial volume effects. MT-sensitized bSSFP is an ideal candidate for qMT-analysis in the clinical routine as it provides high-resolution 3D qMT-data of even small brain structures in clinically feasible acquisition times. The present qMT-data can serve as a reference for the characterization of cerebral diseases.

[1]  B. Mädler,et al.  Insights into brain microstructure from the T2 distribution. , 2006, Magnetic resonance imaging.

[2]  Klaus Scheffler,et al.  Intra- And Inter-Scanner Variability of Magnetization Transfer Ratio Using Balanced SSFP , 2009 .

[3]  S. Nelson,et al.  Measurement of in vivo multi-component T2 relaxation times for brain tissue using multi-slice T2 prep at 1.5 and 3 T. , 2006, Magnetic resonance imaging.

[4]  D. Gochberg,et al.  MT effects and T1 quantification in single‐slice spoiled gradient echo imaging , 2008, Magnetic resonance in medicine.

[5]  Christian Enzinger,et al.  MTI of white matter hyperintensities. , 2005, Brain : a journal of neurology.

[6]  R M Henkelman,et al.  Quantitative interpretation of magnetization transfer , 1993, Magnetic resonance in medicine.

[7]  Mark W. Woolrich,et al.  Advances in functional and structural MR image analysis and implementation as FSL , 2004, NeuroImage.

[8]  K. Scheffler,et al.  On the origin of apparent low tissue signals in balanced SSFP , 2006, Magnetic resonance in medicine.

[9]  T. Peters,et al.  High‐resolution T1 and T2 mapping of the brain in a clinically acceptable time with DESPOT1 and DESPOT2 , 2005, Magnetic resonance in medicine.

[10]  I Levesque,et al.  Regional variations in normal brain shown by quantitative magnetization transfer imaging , 2004, Magnetic resonance in medicine.

[11]  R. Balaban,et al.  Magnetization transfer contrast (MTC) and tissue water proton relaxation in vivo , 1989, Magnetic resonance in medicine.

[12]  Chun Yuan,et al.  Cross-relaxation imaging reveals detailed anatomy of white matter fiber tracts in the human brain , 2004, NeuroImage.

[13]  Klaus Scheffler,et al.  Quantitative Magnetization Transfer Imaging in Acute Stroke: A Follow Up Study Correlating Quantitative MRI with Respect of Severity of Stroke , 2010 .

[14]  M. Bronskill,et al.  T1, T2 relaxation and magnetization transfer in tissue at 3T , 2005, Magnetic resonance in medicine.

[15]  John C Gore,et al.  Quantitative magnetization transfer imaging via selective inversion recovery with short repetition times , 2007, Magnetic resonance in medicine.

[16]  G. B. Pike,et al.  Quantitative imaging of magnetization transfer exchange and relaxation properties in vivo using MRI , 2001, Magnetic resonance in medicine.

[17]  G J Barker,et al.  Estimation of the macromolecular proton fraction and bound pool T2 in multiple sclerosis. , 2004, Multiple sclerosis.

[18]  A. Mackay,et al.  In vivo measurement of T2 distributions and water contents in normal human brain , 1997, Magnetic resonance in medicine.

[19]  John Homer,et al.  Conditions for the driven equilibrium single pulse observation of spin-lattice relaxation times , 1987 .

[20]  Klaus Scheffler,et al.  Analysis of Brain Tumors and Metastases by Quantitative MT Imaging with BSSFP: Initial Experiences , 2010 .

[21]  Vasily L Yarnykh,et al.  Pulsed Z‐spectroscopic imaging of cross‐relaxation parameters in tissues for human MRI: Theory and clinical applications , 2002, Magnetic resonance in medicine.

[22]  Mark A. van Buchem,et al.  MT: magnetization transfer , 2003 .

[23]  K Scheffler,et al.  Optimized balanced steady‐state free precession magnetization transfer imaging , 2007, Magnetic resonance in medicine.

[24]  G. B. Pike,et al.  Magnetization transfer MR of the normal adult brain. , 1995, AJNR. American journal of neuroradiology.

[25]  K. Scheffler,et al.  Quantitative magnetization transfer imaging using balanced SSFP , 2008, Magnetic resonance in medicine.

[26]  Gareth J. Barker,et al.  Three-dimensional quantitative magnetisation transfer imaging of the human brain , 2005, NeuroImage.

[27]  M Filippi,et al.  Magnetization transfer imaging to monitor the evolution of individual multiple sclerosis lesions. , 1999, Neurology.

[28]  G. Barker,et al.  Precise estimate of fundamental in-vivo MT parameters in human brain in clinically feasible times. , 2002, Magnetic resonance imaging.

[29]  R W Cox,et al.  AFNI: software for analysis and visualization of functional magnetic resonance neuroimages. , 1996, Computers and biomedical research, an international journal.

[30]  P. Tofts.  Quantitative MRI of the Brain , 2003 .

[31]  Jimmy Lee,et al.  Reproducibility of myelin water fraction analysis: a comparison of region of interest and voxel-based analysis methods. , 2009, Magnetic resonance imaging.

[32]  A. Okumura,et al.  The characterization of human brain tumor using magnetization transfer technique in magnetic resonance imaging. , 1999, Neurological research.

[33]  A. MacKay,et al.  Magnetic resonance imaging of myelin , 2007, Neurotherapeutics.

[34]  G J Barker,et al.  Quantitative magnetization transfer mapping of bound protons in multiple sclerosis , 2003, Magnetic resonance in medicine.