Background Major focal white matter lesions in the preterm brain such as periventricular haemorrhagic infarctions (PVHI) are often associated with significant cognitive and motor deficits, which may be due to disrupted connections between central and cortical grey matter. Probabilistic diffusion tractography allows connectivity between the thalamus and cortex to be assessed in vivo.
Objective To examine thalamocortical connectivity in preterm infants with unilateral PVHI in the early preterm period and at term equivalent age.
Design and Methods We studied four preterm infants with PVHI born at a median (range) gestational age of 25.4 weeks (24.8–26.7) and imaged at a median (range) corrected age of 29.3 weeks (28–32.1) and at 40.1 weeks (38–42.7). Magnetic resonance imaging was performed on a Philips 3T-system. Diffusion tensor imaging was acquired in 15 non-collinear directions (b-value 750 s/mm2). Data analysis was performed using FSL (www.fmrib.ox.ac.uk/fsl).
Results Altered thalamocortical projections were demonstrated on the ipsilateral side in infants with PVHI depending on the size and site of the lesion. As shown in the figure an infant with left anterior terminal vein infarction had diminished frontal (green), primary motor (red) and primary somatosensory cortex (blue) thalamocortical projections on the ipsilateral side, displayed on a native T2-weighted image (yellow temporal cortex; purple parietal cortex).