Tensor Imaging

Multiple metrics can be calculated from diffusion tensor imaging (DTI) data, typically mean cUffusivity (D ) and fractional 

Brain lesion analysis is also an active area of research. DTI metrics have been found to help differentiate between tumor types and promises to provide a sensitive method for abnormal tissue characterization. Fractional anisotropy has already been found to correlate with the cell density of brain tumors (Beppu et al., 2003 Beppu et al., 2005). The ability of FA to correlate with cell density likely accounts for the sensitivity of FA to tissue typing in brain lesions. Fractional anisotropy has been found to differentiate between low grade and anaplastic astrocytomas, to help differentiate between brain metastasis and high grade gliomas, and there is evidence that FA may help to detect tumor infiltration not visible by conventional MRI (Holmes et al., 2004 Tsuchiya et al., 2005 Goebell et al., 2006). Other DTI metrics have been utilized in brain lesion analysis and the early findings point to the breadth of future possibilities. 

A very exciting and innovative application of DTI and tractography that will have profound clinical application is analysis of brain lesions. There has already been early work defining tumor growth and metastases within major white matter tracts (Witwer et al., 2002 Yu et al., 2005 Hlatky et al.. 

This application will provide measures of white matter tract displacement and tumor invasion that will be defined with great specificity. Previously estimates of white matter tract invasion could only be made by gross estimates of where the white matter tracts were expected to lie based on cross-sectional MRI or CT studies. However, cuiTent mothods of DTI tractography can not reproducibly demonstrate the the true size of fiber bundles (Kinoshita et al., 2005). 

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D. LeBihan, J. F. Mangin, C. Poupon, C.A. Clark, S. Pappata, N. Molko, H. Chabriat 2001, (Diffusion tensor imaging concepts and applications),/. Magn. Reson. Imag. 13, 534—546. 

Sullivan, E. V. and Pfefferbaum, A. diffusion tensor imaging in normal aging and neuropsychiatric disorders. Eur. J. Radiol. 45 244-255, 2003. 

Matusani, Y., Aoky, S., Abe, O., Hayashy, N., and Otomo, K. 2003. MR diffusion tensor imaging Recent advance and new techniques for diffusion tensor visualization. Eur. J. Radiol. 46, 53-66. McCarthy, M.J. and McCarthy, K.L. 1996. Applications of magnetic resonance imaging to food research. Magn. Reson. Imaging 14, 799-802. 

Quantification of White Matter Using Diffusion-Tensor Imaging Hae-Jeong Park... 

Diffusion tensor imaging (DTI) is a sophisticated form of diffusion imaging that is not yet routinely used in clinical stroke. However, it is becoming increasingly popular as a research tool (Sotak 2002), particularly in small lacunar stroke (Gillard et al. 2001 Lie et al. 2004) and in patients with ischemic leukoaraiosis (O Sullivan et al. 2001, 2004), and will, thus, be shortly described here. 

N, Chabriat H (2001) Diffusion tensor imaging concepts and applications. J Magn Reson Imaging 13 534-546... 

Lie C, Hirsch JG, Rossmanith C, Hennerici MG, Gass A (2004) Clinicotopographical correlation of corticospinal tract stroke a color-coded diffusion tensor imaging study. Stroke 35 86-92... 

Thomalla G, Glauche V, Koch MA, Beaulieu C, Weiller C, Rother J (2004) Diffusion tensor imaging detects early Wallerian degeneration of the pyramidal tract after ischemic stroke. Neuroimage 22 1767-1774... 

Liao D, Cooper L, Cai J, Toole J, Bryan N, Burke G, Shahar E, Nieto J, Mosley T, Heiss G (1997) The prevalence and severity of white matter lesions, their relationship with age, ethnicity, gender, and cardiovascular disease risk factors the ARIC Study. Neuroepidemiology 16 149-162 Lie C, Hirsch JG, Rossmanith C, Hennerici MG, Gass A (2004) Clinicotopographical correlation of corticospinal tract stroke a color-coded diffusion tensor imaging study. Stroke. 35 86-92... 

Recently, using color-coded diffusion tensor imaging five different patterns of corticospinal tract stroke were identified that fall into two clinical subgroups with either little recovery or good recovery. Patients with poor motor recovery had lesions centered in the pyramidal tract (anterior choroidal artery). Patients with good recovery had either very small lesions or lesions located anteriorly or medially (Lie et al. 2004). 

Gillard JH, Papadakis NG, Martin K, Price CJ, Warburton EA, Antoun NM et al (2001) MR diffusion tensor imaging of white matter tract disruption in stroke at 3 T. Br J Radiol 74 642-647... 

A review of diffusion tensor imaging studies in schizophrenia. J Psychiatr Res 41 15-30. 

Kanaan RA, Kim JS, Kaufmann WE, Pearlson GD, Barker GJ, et al. 2005. Diffusion tensor imaging in schizophrenia. Biol... 

Addington J, Addington D. 1998. Facial affect recognition and Agartz I, Andersson JL, Skare S. 2001. Abnormal brain white information processing in schizophrenia and bipolar disor- matter in schizophrenia A diffusion tensor imaging study, der. Schizophr Res 32 171-181. Neuroreport 12 2251-2254. 

Diffusion tensor imaging (DTI) is a MRI method that allows examination of white matter integrity by measuring the directional diffusion of water. When there are no structural boundaries, water diffuses in all directions equally. When there are structural barriers, including myelin and cell membranes, diffusion tends... 

Agartz I, Andersson JLR, Share S. 2001. Abnormal brain white matter in schizophrenia A diffusion tensor imaging study. 

Lim KO, Hedehus M, Moseley M, de Crespigny A, Sullivan EV, et al. 1999. Compromised white matter tract integrity in schizophrenia inferred from diffusion tensor imaging. Arch Gen Psychiatry 56 367-374. 

NAA in left FL of patients NAA reduction correlated with severity of negative symptoms and poorer Wisconsin Card Sort performance 4 NAA and diffusion tensor imaging (DTI) anisotropy in medial temporal WM in patients no differences in DLPFC or occipital WM... 

Minati L, Grisoli M, Bruzzone MG. 2007. Mr spectroscopy, functional mri, and diffusion-tensor imaging in the aging brain A conceptual review. J Geriatr Psychiatry Neurol 20 3-21. 

Tang CY, Friedman J, Shungu D, Chang L, Ernst T, et al. 2007. Correlations between diffusion tensor imaging (dti) and magnetic resonance spectroscopy (lh mrs) in schizophrenic patients and normal controls. BMC Psychiatry 7 25. 

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