Fig. 4.
T1 signal within the Posterior Limb of the Internal Capsule (PLIC). Single green arrows indicate normal T1 hyperintensity within the PLIC and single amber arrows indicate normal T1 hyperintensity within the corticospinal tracts. (i) Case series demonstrating progression of T1 signal generated by myelination across range of gestations: A) Preterm infant with absence of myelin signal within the PLIC which appears hypointense due to normal for age high T1 signal within the ventrolateral nucleus posteriorly and globus pallidus anteriorly (double green arrows). B) Very preterm infant imaged during prematurity and again at post-term -demonstrating evolution of myelination of the full length of the PLIC by 49+2 weeks gestation. 64mT scan resolution may preclude visualisation of thin strip of T1 hyperintensity seen on 3T images within the anterior limb of the internal capsule. C) Small amount of T1 myelin signal seen within PLIC bilaterally, infant imaged just prior to their expected delivery date. D) Asymmetry in PLIC signal: small amount of T1 myelin signal on right-side (single red arrow), with abnormal high T1 signal for gestation along the left PLIC (red arrowhead) secondary to extensive left-sided haemorrhagic infarction. (ii) Exemplar 64mT T1w neonatal imaging—multi-inversion time sequence combination facilitates superimposition of PLIC signal alongside white matter, grey matter, and CSF contrast. Pituitary tissue is labelled with a green arrowhead. Ghosting artefact is evident on left-side (blue arrowhead), this requires further investigation. GA: gestational age; PMA: post-menstrual age.