Radiation effects on cerebral white matter: MR evaluation.

Area of Science:

• Neurology
• Radiology
• Oncology

Background:

• Cranial radiation is a common treatment for central nervous system tumors.
• Understanding the neuroimaging effects of radiation is crucial for patient management.

Purpose of the Study:

• To evaluate white-matter changes associated with cranial radiation using Magnetic Resonance (MR) imaging.
• To correlate these changes with radiation parameters and compare them to a control group.

Main Methods:

• Review of MR scans from 95 patients treated with conventional external beam radiation for central nervous system tumors.
• Analysis of T2-weighted spin-echo images for white-matter abnormalities.
• Comparison with 180 age-matched controls with non-irradiated intracranial lesions.

Main Results:

• Radiation-related lesions appeared as symmetric, high-signal foci in the periventricular white matter.
• Sparing of the posterior fossa, basal ganglia, and internal capsules was observed.
• Changes mimicked ischemia in patients over 20 years old and were more prevalent (p < .005).

Conclusions:

• Cerebral white-matter changes mimicking deep white-matter infarction are frequent after therapeutic radiation.
• Radiation effects are variable, more pronounced in older patients.
• Neuropathologic consequences include demyelination, microvascular occlusion, and blood-brain barrier breakdown.