Correlation between Cranial Nerve Microstructural Characteristics and Vestibular Schwannoma Tumor Volume

Area of Science:

• Neuroimaging
• Neurology
• Oncology

Background:

• Vestibular schwannomas are common cerebellopontine angle tumors.
• These tumors arise from the vestibulocochlear nerve, potentially causing cranial nerve dysfunction.
• Conventional MRI lacks detail on nerve compression correlating with symptoms like hearing loss or imbalance.

Purpose of the Study:

• To evaluate the relationship between white matter microstructural properties of cranial nerves and tumor volume in vestibular schwannoma patients.
• To assess if advanced imaging can correlate nerve changes with tumor size.

Main Methods:

• Retrospective study of 160 surgically naive patients with unilateral vestibular schwannomas.
• Utilized 3T MRI and multitensor tractography to extract DTI-derived metrics for facial and vestibulocochlear nerves (cranial nerves VII/VIII).
• Correlated diffusion metrics (fractional anisotropy, radial, axial, mean diffusivities) with 3D tumor volume.

Main Results:

• Significantly higher fractional anisotropy and reduced diffusivities (axial, radial, mean) in affected cranial nerves VII/VIII compared to the unaffected side.
• All specific diffusivities showed an inverse correlation with tumor volume.
• P < .001 for diffusivity changes and P < .01 for correlation with tumor volume.

Conclusions:

• Multitensor tractography quantifies white matter microstructural alterations in cranial nerves VII/VIII due to vestibular schwannomas.
• Tumor volume is associated with microstructural changes in affected cranial nerves.
• Advanced imaging may correlate nerve diffusivities with cranial nerve function.