Interobserver assessment of metabolic patterns in progressive primary aphasia through the application of [¹⁸F]-Fluorodeoxiglucose PET/CT

Our primary objective was to evaluate interobserver variability in [18 F]-FDG PET/CT image interpretation in Primary Progressive Aphasia (PPA). The secondary objective was to determine the utility of [18 F]-FDG PET/CT in differentiating the variants of primary progressive aphasia.

Patients with a clinical diagnosis of unclassifiable PPA or some of its three variants in a neurological referral center were taken. Those who underwent PET/CT study with [¹⁸F]-FDG in the period from 2015 to 2021, obtaining a total of 23 patients who met the inclusion criteria.

The reliability between the two observers was determined for each patient, obtaining a kappa value of 0.67. As well as the Bland Altman graph, which confirms that there was a difference of 0 in 17 patients. The agreement between the two observers was good for the visual analysis. [¹⁸F]-FDG PET/CT was able to differentiate in 100% of patients the variants of PPA.

Overall, the findings of the present study are consistent with previous research on the use of [¹⁸F]-FDG PET/CT in the evaluation of PPA. The study adds to the existing literature by demonstrating the utility of [18F]-FDG PET/CT in differentiating the variants of primary progressive aphasia and by evaluating interobserver variability in image interpretation.