US EPA

1974348 

Journal Article 

The ventral posterolateral thalamus - Magnetic resonance findings in healthy neonates and in neonatal asphyxia 

Korogi, Y; Takahashi, M; Hirai, T; Komohara, Y; Okuda, T; Ikushima, I; Shigematu, Y; Sugahara, T; Aida, N; Miyayama, H 

1998 

Yes 

International Journal of Neuroradiology
ISSN: 1079-8110 

4 

2 

97-104 

WOS:000074046800003 

http://://WOS:000074046800003
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Purpose: This study was conducted to evaluate the magnetic
resonance (MR) signal intensity of the thalamus in the perinatal period, with special attention
to the ventral posterolateral nucleus of the thalamus (VPL thalami); correlate these signals with
the histologic findings from formalin-fixed brains, focusing on myelination; and apply those data
to MR changes in the thalamus in acute profound perinatal asphyxia at term. Methods: In 20
neurologically normal neonates and infants ranging from 37 to 64 weeks postconceptional age, the
MR signal intensity of selected regions of interest were retrospectively compared with the
cerebral cortex on T-1- and T-2-weighted images and graded into three ""stages"" by the consensus
of two radiologists. The formalin-fixed brains from four infants who died of nonneurologic causes
at 37 to 46 weeks postconceptional age were studied microscopically with hematoxylin-eosin and
myelin stains, and the degree of myelination graded from 0 to III, The MR images from 11 full-
term infants who suffered severe acute perinatal asphyxia were evaluated to determine the
anatomic sites at which asphyxia causes injury. Results: The signal intensity of the VPL thalami
differs from the signal of adjacent surrounding nuclear groups during the perinatal period. On
T-2-weighted images, the VPL thalami was hyperintense in relation to cortex between 37 and 45
weeks postconceptional age, On T-2-weighted images, it was markedly hypointense relative to
cortex between 37 and 51 weeks postconceptional age. Review of the histologic specimens at 37 and
40 weeks postconceptional age revealed considerable myelination in the VPL thalami, limited
myelination in the ventral nuclear group, and very little myelination within the medial nuclear
group. The nerve cells were larger in the VPL. thalami than in other. thalamic nuclei. The
lesions seen in asphyctic patients corresponded closely to the VPL thalami, but did not match the
VPL thalami exactly. Conclusion: The normal T-2 shortening of the VPL nucleus in the perinatal
period may reflect a more ""advanced"" myelination and more advanced development of the nerve
cells, The specific location of the asphyctic lesion within the thalamus probably reflects the
susceptibility of the VPL nucleus to profound asphyxia at term. However, other factors also may
contribute to this susceptibility, to account for the imperfect registration between the
asphyctic injury and the VPL nucleus. 

asphyxia, brain, perinatal; birth asphyxia; brain, normal neonatal; myelination; thalamus, ventral posterolateral nucleus