Postshunt lateral ventricular volume, white matter integrity, and intellectual outcomes in spina bifida and hydrocephalus

Abstract

<jats:sec> <jats:title>OBJECT</jats:title> <jats:p>No previous reports exist that have evaluated the relationships of white matter (WM) integrity with the number of shunt revisions, ventricular volume after shunting, and cognition in medically stable children who have spina bifida and hydrocephalus (SBH). The authors hypothesized that enlarged ventricles and a greater number of shunt revisions decrease WM integrity in children.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>In total, 80 children (mean age 13.7 years) who had SBH underwent MRI and IQ testing. Probabilistic diffusion tractography was performed to determine mean diffusion tensor imaging (DTI) metrics along the frontal and parietal tectocortical pathways. The DTI metrics were evaluated for significant correlation with a composite IQ measure and with the total number of shunt revisions and the total lateral ventricular volume obtained through semiautomated parcellation of T1-weighted MRI scans.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>An enlargement in total lateral ventricle volume and an increase in the number of shunt revisions were both associated with higher fractional anisotropy (FA) and with lower radial diffusivity (RD) along both frontal and parietal tectocortical pathways. Children who had not undergone a shunt revision had on average a greater lateral ventricle volume and higher FA and lower RD along frontal and parietal pathways than those who had undergone multiple shunt revisions. The mean DTI metrics along parietal pathways predicted IQ scores, but intellectual ability was not significantly correlated with ventricular volume or with the number of lifetime shunt revisions.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>Significant changes in DTI metrics were observed as a function of ventricular volume. An increased lateral ventricle volume was associated with elevated FA and decreased RD. Given that the participants were medically stable at the time of the MRI examination, the results suggested that those who have enlarged ventricles show a DTI pattern consistent with axonal compression due to increased intracranial pressure (ICP) in attenuated hydrocephalus. Although limited by a cross-sectional design, the study's findings suggest that DTI metrics may serve as sensitive indicators for chronic, mild hydrocephalus in the absence of overt clinical symptoms due to increased ICP. Having enlarged ventricles and undergoing multiple shunt revisions did not affect intellectual ability in children with SBH.</jats:p></jats:sec>

Plasticity of Interhemispheric Temporal Lobe White Matter Pathways Due to Early Disruption of Corpus Callosum Development in Spina Bifida

“…However, recent studies have shown that tracts further from the ventricles, such as parietal tectocortical pathways in SBM (Williams et al, 2013), also show a similar pattern of reduced microstructural integrity, supporting this conclusion in the current study. In addition, Williams et al (2015) also found that increased ventricular volume in SBM was actually a predictor for the opposite pattern of increased FA and reduced RD in frontal and parietal tectocortical pathways. Therefore, it is likely that the group differences in microstructure that we document are not entirely due to the enlargement of ventricles in our patient sample and greater partial volume effects.…”

Long-Term Intellectual and Fine Motor Outcomes in Spina Bifida Are Related to Myelomeningocele Repair and Shunt Intervention History

“…Higher NVIQ scores following greater number of additional shunt revisions may seem paradoxical, but may reflect strong surgical management, especially given that few patients experience more than 5 and no more than 14 revisions. Longitudinal (Air et al, 2010) and cross-sectional (Williams et al, 2015) findings in children with hydrocephalus support attenuation of regionally specific white matter abnormalities following shunt treatment. This intervention can partially restore altered cortical thickness, cortical-subcortical connectivity, and subcortical neurons resulting from hydrocephalus in animals (Aoyama, Kinoshita, Yokota, & Hamada, 2006;Eskandari et al, 2004).…”

The relationship between ventricular volume and whole‐brain irradiation dose in central nervous system germ cell tumors

“…Further studies need to be done regarding neurological outcomes in this population in order to assess the cognitive impact of decreased ventricular volume on long‐term disabilities. Studies in nononcology patients demonstrate such a relationship, with imaging patterns indicating axonal compression with increased intracranial pressure and hydrocephalus . Additionally, literature has shown that the hippocampus is particularly vulnerable to hydrocephalus .…”

“…Studies in nononcology patients demonstrate such a relationship, with imaging patterns indicating axonal compression with increased intracranial pressure and hydrocephalus. 19 Additionally, literature has shown that the hippocampus is particularly vulnerable to hydrocephalus. 20 These findings have been supported in CNS oncology patients, where patients with hydrocephalus requiring shunt placement resulted in a 40% increased risk of memory impairment.…”