Association between postoperative DTI metrics and neurological deficits after posterior fossa tumor resection in children

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Resection of posterior fossa tumors in children may be associated with persistent neurological deficits. It is unclear if these neurological deficits are associated with persistent structural damage to the cerebellar pathways. The purpose of this research was to define longitudinal changes in diffusion tensor imaging (DTI) metrics in white matter cerebellar tracts and the clinical correlates of these metrics in children undergoing resection of posterior fossa tumors.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>Longitudinal brain DTI was performed in a cohort of pediatric patients who underwent resection of posterior fossa tumors. Fractional anisotropy (FA) of the superior cerebellar peduncles (SCPs) and middle cerebellar peduncles (MCPs) was measured on preoperative, postoperative, and follow-up DTI. Early postoperative (&lt; 48 hours) and longer-term follow-up neurological deficits (mutism, ataxia, and extraocular movement dysfunction) were documented. Statistical analysis was performed to determine differences in FA values based on presence or absence of neurological deficits. Statistical significance was set at p &lt; 0.05.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Twenty children (mean age 6.1 ± 4.1 years [SD], 12 males and 8 females) were included in this study. Follow-up DTI was performed at a median duration of 14.3 months after surgery, and the median duration of follow-up was 19.7 months. FA of the left SCP was significantly reduced on postoperative DTI in comparison with preoperative DTI (0.44 ± 0.07 vs 0.53 ± 0.1, p = 0.003). Presence of ataxia at follow-up was associated with a persistent reduction in the left SCP FA on follow-up DTI (0.43 ± 0.1 vs 0.55 ± 0.1, p = 0.016). Patients with early postoperative mutism who did not recover at follow-up had significantly decreased FA of the left SCP on early postoperative DTI in comparison with those who recovered (0.38 ± 0.05 vs 0.48 ± 0.06, p = 0.04).</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>DTI after resection of posterior fossa tumors in children shows that persistent reduction of SCP FA is associated with ataxia at follow-up.</jats:p></jats:sec>

Spatiotemporal changes in along-tract profilometry of cerebellar peduncles in cerebellar mutism syndrome

“…Reports in healthy children 9 and adults 44 indicate no differences in FA or other diffusion MRI metrics between left and right DRTC tracts. However, many of the aforementioned studies have drawn different conclusions as to the required laterality of SCP damage in CMS; be it left 15 – which our results are in agreement with – right 19 , or bilateral 12,14,36,37,45 . These differences may be due in part to the small sample sizes seen in many of these reports, and collaborative multi-centre approaches to tackle this problem may provide more definitive answers.…”

“…A longitudinal study at three timepoints (pre-op, post-op and 1 year follow-up) showed statistically significant post-operative reductions in FA of both SCPs which persisted up to 1 year 14 . A similarly designed study showed post-operative reductions in FA in the left SCP only, and these changes were persistent in patients with ongoing ataxia at delayed follow-up imaging, but not in those with ongoing symptoms of mutism 15 . Neither of the latter two studies demonstrated pre-operative changes in FA at the SCP in patients who went on to develop CMS 14 15 ,.…”

“…A similarly designed study showed post-operative reductions in FA in the left SCP only, and these changes were persistent in patients with ongoing ataxia at delayed follow-up imaging, but not in those with ongoing symptoms of mutism 15 . Neither of the latter two studies demonstrated pre-operative changes in FA at the SCP in patients who went on to develop CMS 14 15 ,.…”

“…SCP ROIs in Vedantam et al . 15 were placed on three axial slices, with FA results averaged across these slices. McEvoy et al .…”

Pre- and Post-Surgical Dysphagia in Adults with Tumors of the Posterior Fossa: A Prospective Blinded Study

“…Additionally, we neither performed a dedicated analysis of brain magnetic resonance imaging nor are tractography data available, thus limiting insight into additional factors leading to postsurgical dysphagia beside from surgical intervention. Future studies, including techniques like, e.g., diffusion tensor imaging (DTI), are warranted to address this issue in order to fully understand the nature of dysphagia following posterior fossa surgery [25][26][27].…”