Altered Brain Glucose Consumption in Cogan's Syndrome

Area of Science:

• Neurology
• Nuclear Medicine
• Immunology

Background:

• Cogan's syndrome (CS) is a rare autoimmune disorder affecting the eyes and inner ears.
• Potential central nervous system involvement in CS is not fully understood.
• Assessing brain glucose metabolism can reveal subclinical neurological dysfunction.

Purpose of the Study:

• To investigate alterations in cerebral metabolic rate for glucose (CMRglc) in patients with Cogan's syndrome (CS).
• To compare brain glucose metabolism across different clinical subtypes of CS and related autoimmune conditions.
• To evaluate the utility of FDG-PET/CT in assessing neurological involvement in CS.

Main Methods:

• Prospective, controlled cohort study design.
• Quantitative molecular imaging using 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT).
• Patients categorized into typical CS, atypical CS (ACS), autoimmune inner ear disease (AIED), and a control group (CG).

Main Results:

• Significant brain glucose hypometabolism was detected in all patient groups (CS, ACS, AIED) compared to controls.
• The most extensive hypometabolism was observed in the typical CS group.
• Altered CMRglc was present even in patients without neurological complaints or abnormal conventional neuroimaging.

Conclusions:

• Cogan's syndrome, in all its subforms, is associated with significantly altered cerebral metabolic rate for glucose.
• FDG-PET/CT is a valuable tool for detecting subclinical brain abnormalities in CS.
• This imaging technique aids in the comprehensive assessment of patients with Cogan's syndrome.