Middle Cerebellar Peduncles in Infants with Neonatal Hypoxic Ischemic Encephalopathy

Background: Neonatal hypoxic ischemic encephalopathy (HIE) is a leading cause of brain injury. As the cerebellum is intimately connected to the cerebrum, we hypothesized that in infants with moderate and severe HIE, the cerebellum may be affected even if no overt damage in discernable in MR imaging.

The objective of the study was to correlate diffusion indices of the middle cerebellar peduncles (MCP) to the degree of cerebral injury in infants with HIE.

Methods: Retrospective study in an ongoing prospectively recruited cohort of neonates born after 35 weeks of gestation, diagnosed with moderate to severe (HIE), monitored with aEEG that underwent a brain MRI scan before hospital discharge. Middle cerebellar peduncles (MCP) were delineated using diffusion tensor imaging and tractography (a modality that is used to visualize cerebral white matter tracts). Associations of MCPs` diffusion indices with the Rutherford cerebral MRI injury score, daily aEEG activity and presence of seizures were sought for.

Results: Overall 46 MRI scans were assessed. Forty-three (93%) survived to discharge, seizures were present in 27 (59%) of the infants. MRI was performed at median age of 5 days (range 1-22), the MRI gradings were 0 (29, 63%), 1 (11, 24%), 2 (6, 13%).

Using univariable and multivariable regression models, no significant associations were found between the MRI global score and the MCPs` diffusion parameters, daily aEEG score or seizures.

Conclusions: At the early stage after HIE, the MCP and cerebellum might not be affected by cerebral injury, but changes may develop later in life.