Abstract
Background the emerging technique of diffusion tractography offers the opportunity to visualise white matter tracts in vivo. The aims of this study were to i. visualise and quantify developmental changes in the corticospinal tracts in the preterm brain using diffusion tractography ii. determine whether abnormalities in tract development associated with focal pathology can be identified in these infants.
Methods Subjects: High resolution DTI was obtained on 21 preterm infants who were born at a median (range) gestational age (GA) of 29 (26 - 34) weeks and imaged at a median post-menstrual age (PMA) of 38 (30 - 44) weeks. 17 infants had no evidence of abnormality on MRI and 4 infants had focal lesions. Magnetic resonance imaging: MRI was performed on a 3 Tesla Philips MR system. DTI was acquired in 15 non-colinear directions with a b value of 750 s/mm2 and an image voxel size of 1.75 x 1.75 x 2 mm3. Tractography: Diffusion tractography was performed using fibre assignment by continuous tracking (FACT). Linear regression analysis was performed to test the relationship between mean fibre length, fractional anisotropy (FA) and apparent diffusion coefficient (ADC) and PMA at scan in the infants who had no evidence of abnormality on MRI. In addition, tractography data in infants who had focal lesions were compared to 7 infants with no lesions at term equivalent age (PMA, p = 0.94)
Results Mean extracted fibre length (p < 0.001) and FA increased (p < 0.001) and ADC decreased (p < 0.001) with increasing PMA. Mean fibre length (p = 0.01) and FA (p = 0.005) were reduced in infants with focal lesions.
Conclusions Diffusion tractography can visualise and quantify the developing corticospinal tracts in the preterm brain. These initial results suggest that tractography may be a useful tool for identifying anomalies in tract development associated with pathology.
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Counsell, S., Srinivasan, L., Boardman, J. et al. 71 Diffusion Tractography of the Corticospinal Tracts in the Developing Preterm Brain. Pediatr Res 58, 366 (2005). https://doi.org/10.1203/00006450-200508000-00100
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DOI: https://doi.org/10.1203/00006450-200508000-00100