F-18 FDG PET-CT in patients with recurrent glioma: Comparison with contrast enhanced MRI

AbstarctPurposeThe purpose of the study was to compare the efficacies of FDG PET-CT and contrast enhanced MRI in detection of recurrent gliomas.MethodsNinety histopathologically proven glioma patients with clinical suspicion of recurrence were evaluated. All patients underwent FDG PET-CT scan and contrast enhanced MRI. Combination of clinical follow up, repeat imaging and biopsy (when available) was taken as gold standard.ResultsBased on gold standard criteria, 59 patients were positive and 31 patients were negative for recurrence. Overall sensitivity and specificity of FDG PET-CT were 70% and 97% respectively whereas that for contrast enhanced MRI was 95% and 23%. FDG PET-CT also has higher accuracy (80%) as compared to MRI (70%). FGD PET-CT has lower sensitivity than MRI in all grades, except for Grade II gliomas where their sensitivities are comparable (95% and 90%). Very low specificity of MRI was observed in all grades of tumour (18–33%). In contrast the specificity of FDG PET-CT was high across all grades (83–100%).ConclusionFDG PET-CT is a highly specific modality for detecting recurrence in patients with gliomas and can effectively exclude post therapy changes.