Assessment of IFOF Changes Across Brain Tumor Histotypes: Italian Multicenter Study

Overview

This multicenter retrospective study analyzed neuroradiological and morphometric changes of the Inferior Fronto-Occipital Fasciculus (IFOF) in 1294 patients with glioblastoma, low-grade glioma, metastasis, and meningioma. The study highlights distinct tumor growth patterns affecting the IFOF, emphasizing the importance of preserving this tract to maintain neurological function during neuro-oncological surgery.

Background

Neuro-oncological surgery has shifted focus from maximal tumor resection to preserving neurological function and quality of life, necessitating detailed knowledge of brain white matter tracts. The IFOF is a major association fiber connecting occipito-parietal and frontal lobes, critical for communication and advanced mentalization. Different brain tumor histotypes exhibit varying growth patterns that impact subcortical white matter tracts differently. Understanding these interactions is essential for optimizing surgical strategies that balance oncological control with functional preservation.

Data Highlights

The study retrospectively reviewed 1294 adult patients operated on for intracranial glioblastoma (GBM), low-grade glioma (LGG), metastasis, and meningioma across six Italian neurosurgical centers in 2023. MRI protocols included T1-weighted, FLAIR, and Diffusion Tensor Imaging (DTI) with 32 to 64 directions. IFOF tractography was reconstructed bilaterally using deterministic methods with a minimum streamline length of 50 mm and FA threshold of 0.15. Tumors were classified into four groups: A) GBM, B) LGG, C) metastasis, and D) meningioma, all located near the IFOF course.

Key Findings

• GBM tends to displace and push the IFOF fiber bundles rather than infiltrate them, often creating a pseudo-plane facilitating tumor disconnection from functional brain tissue.
• Low-grade gliomas and metastases show different patterns of interaction with the IFOF, potentially affecting tract integrity variably.
• Meningiomas, due to their extra-axial origin, may compress but less frequently infiltrate the IFOF.
• Preservation of the IFOF is critical given its role in communication and advanced cognitive functions, influencing surgical planning.
• DTI tractography is a valuable tool for preoperative mapping of the IFOF to guide safe resection strategies.

Clinical Implications

Surgeons should incorporate detailed preoperative DTI tractography of the IFOF to tailor surgical approaches based on tumor histotype and growth pattern. Recognizing the displacement versus infiltration behavior of tumors relative to the IFOF can help optimize the balance between maximal safe resection and functional preservation. This approach supports improved postoperative neurological outcomes and quality of life.

Conclusion

This study underscores the heterogeneous impact of different brain tumor histotypes on the IFOF and highlights the necessity of individualized surgical planning using advanced neuroradiological techniques to preserve critical white matter pathways. Understanding these morphometric changes is pivotal for advancing neuro-oncological surgery toward functional preservation.

References

1. Corbetta et al. 2023 -- Role of Brain Connections in Glioblastoma Location and Spread
2. Feconja et al. -- ROI Placement for IFOF Tractography
3. Recent Neuro-Oncological Surgery Paradigm Shifts