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Updated: Jun 26, 2026
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Published on: February 19, 2021
Abnormal white matter signal on MR imaging is related to abnormal tissue microstructure
J L Y Cheong1, D K Thompson, H X Wang
1Victorian Infant Brain Studies, Murdoch Children's Research Institute, Parkville, Australia. jeanie.cheong@thewomens.org.au
Background And Purpose:
White matter signal-intensity abnormalities (WMSA) on MR imaging are related to adverse neurodevelopmental outcome in extremely preterm infants. Diffusion tensor imaging (DTI) may detect alterations in cerebral white matter microstructure and thus may help confirm the pathologic basis of WMSA. This study aimed to relate regional DTI measures with severity of WMSA in very preterm infants.
Materials And Methods:
One hundred eleven preterm infants (birth weight, <1250 g and/or gestational age, <30 weeks) were scanned at term-equivalent age (1.5T). WMSA were classified as normal, focal, or extensive. Apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial (lambda1), and radial ([lambda2 + lambda3]/2) diffusivity were calculated in 12 regions of interest placed in the bilateral posterior limbs of the internal capsule, frontal (superior and inferior), sensorimotor, and occipital (superior and inferior) white matter regions. Data were compared by using 1-way analysis of variance, with a Bonferroni correction for multiple comparisons.
Results:
Thirty-nine infants had normal, 59 infants had focal, and 13 infants had extensive WMSA. Compared with infants with normal or focal WMSA, infants with extensive WMSA had significantly lower FA in the internal capsule (P < .001), right inferior frontal regions (P < .05), and right superior occipital regions (P = .01); and higher radial diffusivity in the right internal capsule (P = .005), bilateral sensorimotor (P < .05), and right superior occipital regions (P < .05). Compared with infants with normal WMSA, infants with extensive WMSA had significantly higher ADC in bilateral sensorimotor regions (P < .01) and right superior occipital regions (P = .01), and lower axial diffusivity in the bilateral sensorimotor regions (P < .05).
Conclusions:
There are significant region-specific changes in ADC, FA, radial diffusivity, and axial diffusivity in preterm infants with extensive WMSA. Altered radial diffusivity was most prominent. This implies that disrupted premyelinating oligodendroglia is the major correlate with extensive WMSA rather than axonal pathology.
Insights
Extensive white matter signal abnormalities in preterm infants are linked to altered brain microstructure. Radial diffusivity changes were most prominent, suggesting disrupted oligodendroglia, not axonal damage.
Area of Science:
- Neuroimaging
- Neonatal Neurology
- Diffusion Tensor Imaging
Background:
- White matter signal-intensity abnormalities (WMSA) on MRI are associated with poor neurodevelopmental outcomes in extremely preterm infants.
- Diffusion tensor imaging (DTI) can reveal microstructural white matter changes, potentially explaining WMSA pathology.
Purpose of the Study:
- To correlate regional DTI measures with the severity of WMSA in very preterm infants.
- To investigate microstructural white matter differences in relation to WMSA extent.
Main Methods:
- 111 preterm infants (<1250g birth weight and/or <30 weeks gestational age) underwent DTI at term-equivalent age.
- WMSA were classified as normal, focal, or extensive.
- Apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial diffusivity (lambda1), and radial diffusivity were measured in 12 white matter regions.
Main Results:
- Infants with extensive WMSA showed significantly lower FA in the internal capsule and frontal/occipital regions compared to those with normal or focal WMSA.
- Extensive WMSA was associated with higher radial diffusivity in the internal capsule, sensorimotor, and occipital regions.
- Higher ADC and lower axial diffusivity were observed in sensorimotor and occipital regions in infants with extensive WMSA.
Conclusions:
- Region-specific alterations in ADC, FA, and diffusivity are present in preterm infants with extensive WMSA.
- Disrupted radial diffusivity was the most significant finding, indicating premyelinating oligodendroglia pathology.
- Extensive WMSA is primarily correlated with oligodendrocyte injury rather than axonal damage.
