[¹⁸ F]AV-1451 tau-PET and primary progressive aphasia

Area of Science:

• Neuroimaging
• Neurology
• Nuclear Medicine

Background:

• Primary progressive aphasia (PPA) encompasses several neurodegenerative conditions affecting language.
• Accurate differentiation of PPA variants is crucial for prognosis and management.
• Existing imaging modalities like MRI and FDG-PET have limitations in definitively distinguishing PPA subtypes.

Purpose of the Study:

• To investigate [¹⁸ F]AV-1451 tau-PET uptake patterns in logopenic, semantic, and agrammatic PPA variants.
• To identify regional tau deposition patterns independent of clinical diagnosis.
• To compare the diagnostic utility of [¹⁸ F]AV-1451 tau-PET with FDG-PET and MRI for PPA variant differentiation.

Main Methods:

• Statistical parametric mapping of [¹⁸ F]AV-1451 tau-PET in 40 PPA patients and 80 controls.
• Principal component analysis of regional tau-PET uptake to identify underlying patterns.
• Penalized multinomial regression to assess diagnostic performance of imaging modalities.

Main Results:

• Logopenic-PPA exhibited widespread neocortical [¹⁸ F]AV-1451 uptake, particularly temporoparietal.
• Semantic-PPA showed elevated uptake in anteromedial temporal lobes, while agrammatic-PPA demonstrated uptake in prefrontal white matter and subcortical gray matter.
• Principal component analysis revealed distinct dimensions of tau deposition severity and distribution differentiating PPA variants.
• Diagnostic utility of [¹⁸ F]AV-1451 tau-PET was superior to MRI and comparable to FDG-PET.

Conclusions:

• [¹⁸ F]AV-1451 tau-PET binding patterns differ significantly across PPA variants.
• This tau-PET tracer effectively distinguishes between PPA subtypes.
• [¹⁸ F]AV-1451 tau-PET shows promising clinical diagnostic utility for PPA, potentially outperforming other imaging methods.