Diffusion tensor MR imaging tractography of the pyramidal tracts correlates with clinical motor function in children with congenital hemiparesis

Department of Radiology, University of California, San Francisco, CA 94143-0628, USA.
American Journal of Neuroradiology (Impact Factor: 3.68). 10/2007; 28(9):1796-802. DOI: 10.3174/ajnr.A0676
Source: PubMed

ABSTRACT Children with congenital hemiparesis have greater asymmetry in diffusion parameters of the pyramidal tracts compared with control subjects. We hypothesized that the asymmetry correlates with the severity of hemiparesis and that diffusion metrics would be abnormal in the affected tracts and normal in the unaffected tracts.
Fifteen patients with congenital hemiparesis and 17 age-matched control subjects were studied with diffusion tensor MR imaging tractography. Hemipareses were scored as mild, moderate, or severe. We measured tract-specific diffusion parameters (fractional anisotropy, mean, and directional diffusion coefficients) of the pyramidal tracts. We compared tract-specific parameters and asymmetry between the right and left tracts of the differing severity groups and control subjects.
We observed many different causes of congenital hemiparesis including venous infarction, arterial infarction, and polymicrogyria. Clinical severity of hemiparesis correlated with asymmetry in fractional anisotropy (P < .0001), transverse diffusivity (P < .0001), and mean diffusivity (P < .03). With increasing severity of hemiparesis, fractional anisotropy decreased (P < .0001) and transverse diffusivity (P < .0001) and mean diffusivity (P < .02) increased in the affected pyramidal tract compared with controls. Diffusion metrics in the unaffected tract were similar to those in the control subjects.
Asymmetry in fractional anisotropy, transverse diffusivity, and mean diffusivity, as well as the degree of abnormality in the actual values of the affected pyramidal tracts themselves, correlates with the severity of motor dysfunction in infants and children with congenital hemiparesis from different causes. This suggests that abnormalities detected by diffusion tensor MR imaging tractography in the affected pyramidal tract are related to the functional ability of the affected pyramidal tract, regardless of the etiology of motor dysfunction.

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Available from: Jeffrey I Berman, Jan 06, 2014
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    • "Both diffusion MRI and tractography have previously been used to investigate CP in paediatric populations (see Scheck et al., 2012 for a systematic review). Perhaps not surprisingly, the corticospinal tract – the major descending motor pathway in the brain – has been the most frequent target of tractography investigations in CP (Chang et al., 2012; Chaturvedi et al., 2012; Glenn et al., 2007; Holmström et al., 2011; Hoon et al., 2002; Koerte et al., 2011; Rha et al., 2012; Rose et al., 2011; Son et al., 2007, 2009; Thomas et al., 2005; Trivedi et al., 2010; Yoshida et al., 2010), with a recently increased interest in ascending sensory pathways (Chaturvedi et al., 2012; Hoon et al., 2002; Rha et al., 2012; Rose et al., 2011; Thomas et al., 2005; Trivedi et al., 2010; Yoshida et al., 2010). Other projection, association and commissural pathways have been investigated less frequently (Koerte et al., 2011; Thomas et al., 2005). "
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