The in vivo influence of white matter fiber orientation towards B0 on T2* in the human brain

It is well known that, at higher field strength, T2*‐weighted images show an extensive heterogeneity in white matter fiber bundles. The basis of this phenomenon is still under discussion, as many factors, such as iron concentration, myelination and tissue microstructure, could influence relaxation times. Furthermore, fiber direction in relation to the main magnetic field seems to influence T2* relaxation times. In this study, diffusion tensor imaging and T2* measurements were combined in seven subjects with the head in a normal and tilted position. It was shown that fiber orientation has a strong influence on T2* in the human brain, with the average T2* value changing from 49 ms for a perpendicular orientation to B0 to 57 ms for a parallel orientation to B0. Nevertheless, T2* times showed a wide variety of values at any orientation towards B0. Copyright © 2010 John Wiley & Sons, Ltd.

[1]  F. Fazekas,et al.  Pathologic correlates of incidental MRI white matter signal hyperintensities , 1993, Neurology.

[2]  E. Haacke,et al.  Theory of NMR signal behavior in magnetically inhomogeneous tissues: The static dephasing regime , 1994, Magnetic resonance in medicine.

[3]  M. Bronskill,et al.  Anisotropy of NMR properties of tissues , 1994, Magnetic resonance in medicine.

[4]  K Kuppusamy,et al.  In vivo regional cerebral blood volume: quantitative assessment with 3D T1-weighted pre- and postcontrast MR imaging. , 1996, Radiology.

[5]  W R Reinus,et al.  Quantitation of T2′ anisotropic effects on magnetic resonance bone mineral density measurement , 1997, Magnetic resonance in medicine.

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

[7]  M. Cavaglià,et al.  Regional variation in brain capillary density and vascular response to ischemia , 2001, Brain Research.

[8]  D. Yablonskiy,et al.  Water proton MR properties of human blood at 1.5 Tesla: Magnetic susceptibility, T1, T2, T  *2 , and non‐Lorentzian signal behavior , 2001, Magnetic resonance in medicine.

[9]  Tadashi Nagayama,et al.  Microvasculature of the human cerebral white matter: Arteries of the deep white matter , 2003, Neuropathology : official journal of the Japanese Society of Neuropathology.

[10]  Derek K. Jones,et al.  The effect of gradient sampling schemes on measures derived from diffusion tensor MRI: A Monte Carlo study † , 2004, Magnetic resonance in medicine.

[11]  M. Robson,et al.  Magic angle effects in MR neurography. , 2004, AJNR. American journal of neuroradiology.

[12]  E. Haacke,et al.  Imaging iron stores in the brain using magnetic resonance imaging. , 2005, Magnetic resonance imaging.

[13]  Jeff H. Duyn,et al.  Extensive heterogeneity in white matter intensity in high-resolution T2 *-weighted MRI of the human brain at 7.0 T , 2006, NeuroImage.

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

[15]  D. Yablonskiy,et al.  Quantitative BOLD: Mapping of human cerebral deoxygenated blood volume and oxygen extraction fraction: Default state , 2007, Magnetic resonance in medicine.

[16]  Yiping P. Du,et al.  Fast multislice mapping of the myelin water fraction using multicompartment analysis of T  2* decay at 3T: A preliminary postmortem study , 2007, Magnetic resonance in medicine.

[17]  C. Crandall,et al.  Narrative Review: Hyperkyphosis in Older Persons , 2007, Annals of Internal Medicine.

[18]  Alex J. de Crespigny,et al.  The effects of brain tissue decomposition on diffusion tensor imaging and tractography , 2007, NeuroImage.

[19]  D. Le Bihan,et al.  Orientation Dependence of White Matter T 2 * Contrast at 7 T : A Direct Demonstration , 2007 .

[20]  A. Gjedde,et al.  Improvement of brain tissue oxygenation by inhalation of carbogen , 2008, Neuroscience.

[21]  Robert Turner,et al.  Understanding the orientation dependent T2* contrast of the cingulum in ultra high fields , 2009 .

[22]  Shu-Wei Sun,et al.  Fixation, not death, reduces sensitivity of DTI in detecting optic nerve damage , 2009, NeuroImage.

[23]  Carlo Caltagirone,et al.  Characterization of white matter fiber bundles with T  2* relaxometry and diffusion tensor imaging , 2009, Magnetic resonance in medicine.

[24]  Uwe Klose,et al.  Cerebrospinal fluid and interstitial fluid volume measurements in the human brain at 3T with EPI , 2009, Magnetic resonance in medicine.

[25]  Rolf Gruetter,et al.  On the origin of the MR image phase contrast: An in vivo MR microscopy study of the rat brain at 14.1 T , 2009, NeuroImage.

[26]  D. Yablonskiy,et al.  Biophysical mechanisms of phase contrast in gradient echo MRI , 2009, Proceedings of the National Academy of Sciences.

[27]  Pierre Jannin,et al.  Construction and assessment of a 3-T MRI brain template , 2010, NeuroImage.