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Time-dependent structural changes of the dentatothalamic pathway in children treated for posterior fossa tumor
S Perreault1, R M Lober, S Cheshier
1From the Departments of Neurology (S. Perreault, S. Partap).
Insights
Pediatric posterior fossa tumor treatment can damage the dentatothalamic pathway. Diffusion MRI shows initial inflammation and recovery in white matter, but chronic damage and volume loss in dentate nuclei suggest lasting injury.
Area of Science:
- Pediatric neuro-oncology
- Neuroimaging
- Cerebellar pathway anatomy
Background:
- Posterior fossa tumors are common in children.
- Neurologic complications can arise from damage to the dentatothalamic pathway.
- The dentatothalamic pathway connects the cerebellum to the thalamus.
Purpose of the Study:
- To investigate time-dependent changes in the dentatothalamic pathway after posterior fossa tumor treatment in children.
- To hypothesize that structural alterations evolve over time post-surgery.
Main Methods:
- Diffusion tensor imaging (DTI) was used in 14 pediatric patients.
- Serial MRI scans were acquired at 3T in acute, subacute, and chronic phases post-surgery.
- DTI metrics and dentate nuclei volumes were analyzed in the cerebellar white matter, superior cerebellar peduncles, and dentate nuclei.
Main Results:
- Superior cerebellar peduncles and cerebellar white matter showed significant tensor changes in the subacute phase, with partial recovery in the chronic phase.
- Dentate nuclei exhibited chronic volume loss and reduced mean diffusivity, indicating persistent injury.
- Atrophy in dentate nuclei correlated with radiation therapy and ataxia symptoms.
Conclusions:
- Longitudinal DTI reveals time-dependent structural changes in the dentatothalamic pathway following pediatric posterior fossa tumor resection.
- While some pathway components show recovery, dentate nuclei injury appears chronic and irreversible.
- These findings highlight the potential for long-term neurologic deficits in children treated for these tumors.
Background And Purpose:
Injury to the dentatothalamic pathway that originates in the cerebellum has been suggested as a mechanism for neurologic complications in children treated for posterior fossa tumors. We hypothesized that time-dependent changes occur in the dentatothalamic pathway.
Materials And Methods:
Diffusion tensor evaluation was performed in 14 children (median age, 4.1 years; age range, 1-20 years) who underwent serial MR imaging at 3T as part of routine follow-up after posterior fossa tumor resection with or without adjuvant therapy. Tensor metrics were obtained in the acute (≤1 week), subacute (1 to <6 months), and chronic (≥6 months) periods after surgery. We evaluated the following dentatothalamic constituents: bilateral dentate nuclei, cerebellar white matter, and superior cerebellar peduncles. Serial dentate nuclei volumes were also obtained and compared with the patient's baseline.
Results:
The most significant tensor changes to the superior cerebellar peduncles and cerebellar white matter occurred in the subacute period, regardless of the tumor pathology or therapy regimen, with signs of recovery in the chronic period. However, chronic volume loss and reduced mean diffusivity were observed in the dentate nuclei and did not reverse. This atrophy was associated with radiation therapy and symptoms of ataxia.
Conclusions:
Longitudinal diffusion MR imaging in children treated for posterior fossa tumors showed time-dependent tensor changes in components of the dentatothalamic pathway that suggest evolution of structural damage with inflammation and recovery of tissue directionality. However, the dentate nuclei did not show tensor or volumetric recovery, suggesting that the injury may be chronic.
