Chiasmal gliomas: appearance and long-term changes demonstrated by computerized tomography

Area of Science:

• Neuro-oncology
• Radiology
• Ophthalmology

Background:

• Chiasmal gliomas represent a spectrum of lesions affecting the optic nerve and chiasm.
• Accurate diagnosis and treatment planning are crucial for managing these tumors.

Purpose of the Study:

• To evaluate the diagnostic utility of computerized tomography (CT) in characterizing chiasmal gliomas.
• To correlate CT findings with clinical presentation, tumor growth, and treatment outcomes.

Main Methods:

• Retrospective analysis of 22 cases of chiasmal gliomas.
• Detailed review of computerized tomography (CT) scans to identify characteristic patterns.
• Correlation of imaging findings with histological diagnoses and clinical data.

Main Results:

• Three CT patterns were diagnostic: tubular thickening of the optic nerve/chiasm, suprasellar tumor with optic nerve expansion, or optic tract involvement.
• Globular suprasellar tumors without these features required histological examination.
• CT documented tumor growth in only globular-type gliomas; visual function was not a reliable indicator of growth.
• Neurofibromatosis was associated with tubular optic nerve thickening and unilateral optic nerve expansion.
• Radiation therapy led to tumor shrinkage in five cases, with complications including calcification and infarcts.
• CT could not differentiate between juvenile pilocytic astrocytoma and anaplastic astrocytoma.

Conclusions:

• Computerized tomography (CT) is instrumental in diagnosing and guiding the neurosurgical management of chiasmal gliomas.
• CT findings help determine the necessity for biopsy or ventricular shunting.
• Histological examination remains essential for specific tumor type differentiation.