Exploring the thalamus L-sign: initial findings and associations with white matter injury in premature infants

Abstract

Abstract Background The thalamus L-sign, characterized by damage to the lateral and posterior parts of the thalamus, has recently been identified as a potential marker of partial prolonged hypoxic-ischemic injury (HII). Although prematurity-related thalamic injury is well documented, its association with the thalamus L-sign is infrequently described. Objective The primary objective of this study was to further investigate the thalamus L-sign in premature birth and white matter injury. Materials and methods A retrospective analysis of 246 brain magnetic resonance imaging (MRI) scans from preterm infants born before 37 weeks of gestation was conducted to explore the occurrence, characteristics, and associations of the thalamus L-sign with white matter injury. Results The L-sign was detected in 12.6% of patients with periventricular leukomalacia (PVL), primarily in severe cases (57.9% of severe PVL). All cases were associated with posterior parieto-occipital PVL. Four patients exhibited unilateral or asymmetric L-signs, which were linked to high-grade intraventricular hemorrhage (IVH) or periventricular hemorrhagic infarction on the ipsilateral side, with the most severe white matter injury occurring on that side. No significant differences were observed regarding gestational age at birth, duration of neonatal intensive care unit hospitalization, percentage of IVH, hypoglycemia, or jaundice between patients with moderate-to-severe PVL with and without the thalamus L-sign. Conclusion The thalamus L-sign may serve as a marker for severe parieto-occipital PVL and may be exacerbated and appear asymmetric in cases of ipsilateral IVH or periventricular hemorrhagic infarction. Graphical Abstract