Periventricular hyperintensity in children with hydrocephalus

Abstract

Background: Magnetic resonance images of children with hydrocephalus often include a rim of hyperintensity in the periventricular white matter (halo).

Objective: The purpose of this study was to decide between the hypothesis that the halo is caused by cerebrospinal fluid (CSF) flow during the cardiac cycle, and the alternate hypothesis that the halo is caused by anatomical changes (stretching and compression of white matter).

Materials and methods: Participants were selected from a multicenter imaging study of pediatric hydrocephalus. We compared 19 children with hydrocephalus to a group of 52 controls. We quantified ventricle enlargement using the frontal-occipital horn ratio. We conducted qualitative and quantitative analysis of diffusion tensor imaging in the corpus callosum and posterior limb of the internal capsule. Parameters included the fractional anisotropy (FA), mean diffusivity, axial diffusivity and radial diffusivity.

Results: The halo was seen in 16 of the 19 children with hydrocephalus but not in the controls. The corpus callosum of the hydrocephalus group demonstrated FA values that were significantly decreased from those in the control group (P = 4 · 10(-6)), and highly significant increases were seen in the mean diffusivity and radial diffusivity in the hydrocephalus group. In the posterior limb of the internal capsule the FA values of the hydrocephalus group were higher than those for the control group (P = 0.002), and higher values in the hydrocephalus group were also noted in the axial diffusivity. We noted correlations between the diffusion parameters and the frontal-occipital horn ratio.

Conclusion: Our results strongly support the hypothesis that the halo finding in hydrocephalus is caused by structural changes rather than pulsatile CSF flow.

Fig. 1

Axial fractional anisotropy images in a 26-month-old boy with hydrocephalus (a) and a 48-month-old male control (b) at the level of region-of-interest selection. Mean diffusivity images in hydrocephalus (c) and control (d) patients demonstrate no periventricular white matter hyperintensity. Arrows in (a) point to the halo. Sample regions of interest are marked on (a) and (b)

Fig. 1

Axial fractional anisotropy images in a 26-month-old boy with hydrocephalus (a) and a 48-month-old male control (b) at the level of region-of-interest selection. Mean diffusivity images in hydrocephalus (c) and control (d) patients demonstrate no periventricular white matter hyperintensity. Arrows in (a) point to the halo. Sample regions of interest are marked on (a) and (b)

Fig. 1

Axial fractional anisotropy images in a 26-month-old boy with hydrocephalus (a) and a 48-month-old male control (b) at the level of region-of-interest selection. Mean diffusivity images in hydrocephalus (c) and control (d) patients demonstrate no periventricular white matter hyperintensity. Arrows in (a) point to the halo. Sample regions of interest are marked on (a) and (b)

Fig. 1

Axial fractional anisotropy images in a 26-month-old boy with hydrocephalus (a) and a 48-month-old male control (b) at the level of region-of-interest selection. Mean diffusivity images in hydrocephalus (c) and control (d) patients demonstrate no periventricular white matter hyperintensity. Arrows in (a) point to the halo. Sample regions of interest are marked on (a) and (b)

Fig. 2

Directionally encoded color images in a 26-month-old boy with hydrocephalus (a, c) and a 48-month-old male control (b, d) in transverse (a, b) and coronal (c, d) planes demonstrate decreased intensity of crossing fibers of the corpus callosum (pink, red) and increased intensity of supero-inferior fibers (blue) in the lateral periventricular white matter in the boy with hydrocephalus vs. the control patient

Fig. 2

Directionally encoded color images in a 26-month-old boy with hydrocephalus (a, c) and a 48-month-old male control (b, d) in transverse (a, b) and coronal (c, d) planes demonstrate decreased intensity of crossing fibers of the corpus callosum (pink, red) and increased intensity of supero-inferior fibers (blue) in the lateral periventricular white matter in the boy with hydrocephalus vs. the control patient

Fig. 2

Directionally encoded color images in a 26-month-old boy with hydrocephalus (a, c) and a 48-month-old male control (b, d) in transverse (a, b) and coronal (c, d) planes demonstrate decreased intensity of crossing fibers of the corpus callosum (pink, red) and increased intensity of supero-inferior fibers (blue) in the lateral periventricular white matter in the boy with hydrocephalus vs. the control patient

Fig. 2

Directionally encoded color images in a 26-month-old boy with hydrocephalus (a, c) and a 48-month-old male control (b, d) in transverse (a, b) and coronal (c, d) planes demonstrate decreased intensity of crossing fibers of the corpus callosum (pink, red) and increased intensity of supero-inferior fibers (blue) in the lateral periventricular white matter in the boy with hydrocephalus vs. the control patient

Fig. 3

Diffusion tensor imaging parameter values in the corpus callosum plotted as a function of age for the group with hydrocephalus (red circles) and normal controls (black circles). The black curves are an estimate of the parameter change with age. a, b The fractional anisotropy values (a) in children with hydrocephalus are lower than those in controls (P=4·10⁻⁶) and the mean diffusivity values (b) in children with hydrocephalus are higher than those in the controls (P=2·10⁻⁸). c, d These changes are driven by the significantly larger radial diffusivity values (d) in the hydrocephalus group (P=3·10⁻⁹); the axial diffusivity values (c) are not statistically different (P=0.097)

Fig. 3

Diffusion tensor imaging parameter values in the corpus callosum plotted as a function of age for the group with hydrocephalus (red circles) and normal controls (black circles). The black curves are an estimate of the parameter change with age. a, b The fractional anisotropy values (a) in children with hydrocephalus are lower than those in controls (P=4·10⁻⁶) and the mean diffusivity values (b) in children with hydrocephalus are higher than those in the controls (P=2·10⁻⁸). c, d These changes are driven by the significantly larger radial diffusivity values (d) in the hydrocephalus group (P=3·10⁻⁹); the axial diffusivity values (c) are not statistically different (P=0.097)

Fig. 3

Diffusion tensor imaging parameter values in the corpus callosum plotted as a function of age for the group with hydrocephalus (red circles) and normal controls (black circles). The black curves are an estimate of the parameter change with age. a, b The fractional anisotropy values (a) in children with hydrocephalus are lower than those in controls (P=4·10⁻⁶) and the mean diffusivity values (b) in children with hydrocephalus are higher than those in the controls (P=2·10⁻⁸). c, d These changes are driven by the significantly larger radial diffusivity values (d) in the hydrocephalus group (P=3·10⁻⁹); the axial diffusivity values (c) are not statistically different (P=0.097)

Fig. 3

Diffusion tensor imaging parameter values in the corpus callosum plotted as a function of age for the group with hydrocephalus (red circles) and normal controls (black circles). The black curves are an estimate of the parameter change with age. a, b The fractional anisotropy values (a) in children with hydrocephalus are lower than those in controls (P=4·10⁻⁶) and the mean diffusivity values (b) in children with hydrocephalus are higher than those in the controls (P=2·10⁻⁸). c, d These changes are driven by the significantly larger radial diffusivity values (d) in the hydrocephalus group (P=3·10⁻⁹); the axial diffusivity values (c) are not statistically different (P=0.097)

Fig. 4

Diffusion tensor imaging parameter values in the posterior limb of the internal capsule plotted as a function of age for the group with hydrocephalus (red circles) and normal controls (black circles). The black curves are an estimate of the parameter change with age. a, b The fractional anisotropy values (a) in children with hydrocephalus are higher than those in controls (P=0.002), but the mean diffusivity values (b) are no different between children with hydrocephalus and controls (P=0.23). c The fractional anisotropy changes are driven by the significantly larger axial diffusivity values in children with hydrocephalus (P=4·10⁻⁵). d The radial diffusivity values are not different between groups (P=0.19)

Fig. 4

Diffusion tensor imaging parameter values in the posterior limb of the internal capsule plotted as a function of age for the group with hydrocephalus (red circles) and normal controls (black circles). The black curves are an estimate of the parameter change with age. a, b The fractional anisotropy values (a) in children with hydrocephalus are higher than those in controls (P=0.002), but the mean diffusivity values (b) are no different between children with hydrocephalus and controls (P=0.23). c The fractional anisotropy changes are driven by the significantly larger axial diffusivity values in children with hydrocephalus (P=4·10⁻⁵). d The radial diffusivity values are not different between groups (P=0.19)

Fig. 4

Diffusion tensor imaging parameter values in the posterior limb of the internal capsule plotted as a function of age for the group with hydrocephalus (red circles) and normal controls (black circles). The black curves are an estimate of the parameter change with age. a, b The fractional anisotropy values (a) in children with hydrocephalus are higher than those in controls (P=0.002), but the mean diffusivity values (b) are no different between children with hydrocephalus and controls (P=0.23). c The fractional anisotropy changes are driven by the significantly larger axial diffusivity values in children with hydrocephalus (P=4·10⁻⁵). d The radial diffusivity values are not different between groups (P=0.19)

Fig. 4

Diffusion tensor imaging parameter values in the posterior limb of the internal capsule plotted as a function of age for the group with hydrocephalus (red circles) and normal controls (black circles). The black curves are an estimate of the parameter change with age. a, b The fractional anisotropy values (a) in children with hydrocephalus are higher than those in controls (P=0.002), but the mean diffusivity values (b) are no different between children with hydrocephalus and controls (P=0.23). c The fractional anisotropy changes are driven by the significantly larger axial diffusivity values in children with hydrocephalus (P=4·10⁻⁵). d The radial diffusivity values are not different between groups (P=0.19)

Fig. 5

Linear regression plots between diffusion parameters and the frontal-occipital horn ratio. The dependent parameters are: (a) corpus callosum fractional anisotropy, (b) corpus callosum mean diffusivity, (c) corpus callosum radial diffusivity, and (d) posterior limb of the internal capsule axial diffusivity. Pearson R values and P-values are presented in Table 1. Only plots with significant values are presented

Fig. 5

Linear regression plots between diffusion parameters and the frontal-occipital horn ratio. The dependent parameters are: (a) corpus callosum fractional anisotropy, (b) corpus callosum mean diffusivity, (c) corpus callosum radial diffusivity, and (d) posterior limb of the internal capsule axial diffusivity. Pearson R values and P-values are presented in Table 1. Only plots with significant values are presented

Fig. 5

Linear regression plots between diffusion parameters and the frontal-occipital horn ratio. The dependent parameters are: (a) corpus callosum fractional anisotropy, (b) corpus callosum mean diffusivity, (c) corpus callosum radial diffusivity, and (d) posterior limb of the internal capsule axial diffusivity. Pearson R values and P-values are presented in Table 1. Only plots with significant values are presented

Fig. 5

Linear regression plots between diffusion parameters and the frontal-occipital horn ratio. The dependent parameters are: (a) corpus callosum fractional anisotropy, (b) corpus callosum mean diffusivity, (c) corpus callosum radial diffusivity, and (d) posterior limb of the internal capsule axial diffusivity. Pearson R values and P-values are presented in Table 1. Only plots with significant values are presented