MR signal intensity of the perirolandic cortex in the neonate and infant

Abstract

Our purpose was the study the magnetic resonance (MR) signal intensity of the perirolandic gyri perinatally and to correlate it with the histological findings in formalin-fixed brains, focusing on myelination. MRI of 20 neurologically normal neonates and infants, of 37-64 weeks postconception (PCA), were studied retrospectively. We reviewed four formalin-fixed brains of infants 37-46 weeks PCA microscopically. The posterior cortex of the precentral gyrus (P-PRE) and the anterior cortex of the postcentral gyrus (A-PST) had different signal intensity from the adjacent surrounding cortex. On T1-weighted images P-PRE and A-PST gave higher signal 41-44 weeks PCA; on T2-weighted images, they gave lower signal 37-51 weeks PCA. Histological examination revealed very little myelination of the nerve fibres within both the P-PRE and the A-PST, while considerable myelination was present in the internal capsule and central corona radiata. The changes in signal intensity in the perirolandic gyri may reflect not only the degree of myelination but also the more advanced development of the nerve cells, associated with rapid proliferation and formation of oligodendroglial cells, synapses and dendrites. They could be another important landmark for brain maturation.

Myelination of the Pig’s Brain: A Correlated MRI and Histological Study

“…Recent studies suggested that changes in signal intensity from MR imaging might not only refer to myelination but also to the development of nerve cells (e.g. increase in cells) related to these tracts [24]. In our work, however, morphological observation on the neurons and quantitation by PCNA immunocytochemistry (to show dividing cells) on the specimens of different ages did not identify any significant differences in the percentage of dividing new cells between ages in preliminary studies.…”

Transient Hyperintensity in the Subthalamic Nucleus and Globus Pallidus of Newborns on T1-Weighted Images

“…[1][2][3][4][5][6][7]10 These changes are believed to be mainly due to myelination and a decrease in cerebral water content. 11 There are several studies reporting the time course of this signal intensity change in the term or preterm infant or fetus in terms of gestational age at examination, and those studies successfully proved the signal intensity change in most of the structure in the brain.…”

“…Various processes other than myelination take place within the developing cerebral tissue, including neuronal development, which is associated with the rapid proliferation and formation of oligodendroglial cells, synapses, and dendrites as mentioned above. 5 It also has been suggested that a glutamatergic pathway transiently innervates the globus pallidus during the mammalian perinatal period. 15 This kind of transient innervation may cause synaptic and dendritic formation, resulting in T1 hyperintensity in this region.…”

“…The time course for changes in cerebral signal intensity associated with the progression of myelination in the developing brain also has been described in detail. [1][2][3][4][5][6][7] Compared with unmyelinated areas, myelinated regions of the brain exhibit high signal intensity on T1WI and low signal intensity on T2WI. Although changes in signal intensity in most cerebral structures can be explained by the development of myelination, there are some structures for which signal intensity changes cannot be accounted for by myelination alone.…”

“…Although changes in signal intensity in most cerebral structures can be explained by the development of myelination, there are some structures for which signal intensity changes cannot be accounted for by myelination alone. 5 Patients in our neonate intensive care unit are routinely screened for central nervous system abnormalities by using MR imaging. Certain cases among these have displayed unusual signal intensities with respect to cerebral development.…”