Optic Nerve Sheath Meningiomas: Solving Diagnostic Challenges with ⁶⁸Ga-DOTATOC PET/CT

Area of Science:

• Oncology
• Radiology
• Nuclear Medicine

Background:

• Optic nerve sheath meningioma (ONSM) presents diagnostic challenges, often requiring invasive procedures.
• Magnetic Resonance Imaging (MRI) can yield uncertain diagnoses in most ONSM cases.
• Noninvasive imaging modalities are crucial for accurate ONSM diagnosis and treatment planning.

Purpose of the Study:

• To evaluate the utility and diagnostic performance of Gallium-68 DOTATOC Positron Emission Tomography (⁶⁸Ga-DOTATOC PET) in suspected ONSM.
• To assess the role of ⁶⁸Ga-DOTATOC PET in tumor delineation for radiation therapy planning.
• To determine the impact of ⁶⁸Ga-DOTATOC PET on therapeutic management of ONSM.

Main Methods:

• Retrospective analysis of 12 subjects with suspected ONSM who underwent ⁶⁸Ga-DOTATOC PET.
• Collection of standardized clinical and radiological data.
• Classification of PET results as positive (SUV_max > 5) or negative (SUV_max < 5) and recording of SUV_max values.

Main Results:

• ⁶⁸Ga-DOTATOC PET showed positive uptake in 6 cases, confirming ONSM diagnoses and guiding radiation therapy.
• Negative scans (6 cases) included neurosarcoidosis, cavernous malformation, and uncertain diagnoses requiring further investigation.
• ⁶⁸Ga-DOTATOC PET facilitated accurate tumor volume delineation, potentially reducing radiation dose exposure.

Conclusions:

• ⁶⁸Ga-DOTATOC PET is a sensitive and specific noninvasive tool for ONSM diagnosis, especially when MRI is inconclusive.
• The technique aids in differentiating ONSM from other intraorbital lesions, impacting therapeutic decisions.
• ⁶⁸Ga-DOTATOC PET is recommended before radiotherapy or stereotactic radiosurgery for nonhistologically proven meningiomas.