Diffusion tensor imaging study of pediatric patients with congenital hydrocephalus: 1-year postsurgical outcomes

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>The purpose of this study was to investigate white matter (WM) structural abnormalities using diffusion tensor imaging (DTI) in children with hydrocephalus before CSF diversionary surgery (including ventriculoperitoneal shunt insertion and endoscopic third ventriculostomy) and during the course of recovery after surgery in association with neuropsychological and behavioral outcome.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>This prospective study included 54 pediatric patients with congenital hydrocephalus (21 female, 33 male; age range 0.03–194.5 months) who underwent surgery and 64 normal controls (30 female, 34 male; age range 0.30–197.75 months). DTI and neurodevelopmental outcome data were collected once in the control group and 3 times (preoperatively and at 3 and 12 months postoperatively) in the patients with hydrocephalus. DTI measures, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) values were extracted from the genu of the corpus callosum (gCC) and the posterior limb of internal capsule (PLIC). Group analysis was performed first cross-sectionally to quantify DTI abnormalities at 3 time points by comparing the data obtained in the hydrocephalus group for each of the 3 time points to data obtained in the controls. Longitudinal comparisons were conducted pairwise between different time points in patients whose data were acquired at multiple time points. Neurodevelopmental data were collected and analyzed using the Adaptive Behavior Assessment System, Second Edition, and the Bayley Scales of Infant Development, Third Edition. Correlation analyses were performed between DTI and behavioral measures.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>Significant DTI abnormalities were found in the hydrocephalus patients in both the gCC (lower FA and higher MD, AD, and RD) and the PLIC (higher FA, lower AD and RD) before surgery. The DTI measures in the gCC remained mostly abnormal at 3 and 12 months after surgery. The DTI abnormalities in the PLIC were significant in FA and AD at 3 months after surgery but did not persist when tested at 12 months after surgery. Significant longitudinal DTI changes in the patients with hydrocephalus were found in the gCC when findings at 3 and 12 months after surgery were compared. In the PLIC, trend-level longitudinal changes were observed between preoperative findings and 3-month postoperative findings, as well as between 3- and 12-month postoperative findings. Significant correlation between DTI and developmental outcome was found at all 3 time points. Notably, a significant correlation was found between DTI in the PLIC at 3 months after surgery and developmental outcome at 12 months after surgery.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>The data showed significant WM abnormality based on DTI in both the gCC and the PLIC in patients with congenital hydrocephalus before surgery, and the abnormalities persisted in both the gCC and the PLIC at 3 months after surgery. The DTI values remained significantly abnormal in the gCC at 12 months after surgery. Longitudinal analysis showed signs of recovery in both WM structures between different time points. Combined with the significant correlation found between DTI and neuropsychological measures, the findings of this study suggest that DTI can serve as a sensitive imaging biomarker for underlying neuroanatomical changes and postsurgical developmental outcome and even as a predictor for future outcomes.</jats:p></jats:sec>

Advanced Neuroimaging Techniques in Pediatric Hydrocephalus

“…A recent study published by our group showed that DTI was sensitive in detecting underlying WM changes and correlated highly with improved neurocognitive outcomes after a 6-week iPad application-based occupational therapy intervention in school age children with stable, surgically treated hydrocephalus earlier in life [72] . This study further supports that, when followed longitudinally over time, the DTI parameters may serve to correlate functional outcomes in a similar way to serial head circumference measurements in infants and toddlers to help predict normal development or possible impending clinical pathology [55] .…”

“…In order to further clarify and establish the use of DTI in the management of childhood hydrocephalus, Mangano et al [55] recently published the first multicenter, prospective, longitudinal imaging study of pediatric hydrocephalus investigating both imaging and behavioral outcomes prior to (at baseline) and after surgical management. The study included 54 patients with congenital hydrocephalus who underwent surgery and 64 normal controls.…”

“…Some of the most common ROIs studied in these investigations included the CC, anterior and posterior limb of the internal capsule (IC), corticospinal tract, and superior and inferior longitudinal fasciculus, just to name a few [48,49,51,55,58,61,62] . In 2006, Assaf et al [48] used DTI parameters to study and compare 7 patients (age > 9 years) with acute hydrocephalus with age-matched healthy control subjects.…”

“…Over the last decade, there has been particular interest in investigating WM injury as it relates to hydrocephalus and the use of DTI to provide further insight into both the underlying mechanisms of WM damage and its reversibility with surgical intervention [42,[48][49][50][51][52][53][54][55] . The premise behind the use of DTI emerges from the knowledge that the diffusion of water in tissue is affected by the microstructure and organization, thus providing powerful information regarding the effects of disorders that affect the integrity of the WM [48,49,56] .…”

“…Over the past decade, the evaluation of WM tracts in pediatric hydrocephalus with DTI has been applied both retrospectively and prospectively in both humans and animal studies [42,[49][50][51][52][53][54][55][57][58][59][60] . Some of the most common ROIs studied in these investigations included the CC, anterior and posterior limb of the internal capsule (IC), corticospinal tract, and superior and inferior longitudinal fasciculus, just to name a few [48,49,51,55,58,61,62] .…”