Positron emission tomography in Rasmussen's encephalitis

Area of Science:

• Neurology
• Nuclear Medicine

Background:

• Rasmussen's encephalitis is a rare, chronic inflammatory neurological disease affecting one cerebral hemisphere.
• Early diagnosis and understanding disease progression are crucial for managing Rasmussen's encephalitis.

Observation:

• An 11-year-old male with Rasmussen's encephalitis underwent fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) to identify seizure focus.
• PET revealed significant hypermetabolism in the left cerebral hemisphere and basal ganglia, with reduced activity in the right hemisphere and crossed cerebellar diaschisis.

Findings:

• The heterogeneous metabolic distribution indicated varying stages of ictal and postictal activity.
• Serial PET scans demonstrated disease progression, with the hypermetabolic region expanding over two years.
• This pattern of progression is characteristic but infrequently documented in serial reports.

Implications:

• Complex PET findings highlight the necessity of integrating clinical history, seizure details, and electroencephalography for accurate interpretation.
• FDG-PET can be instrumental in determining surgical eligibility for patients with Rasmussen's encephalitis and dominant hemisphere involvement.