Highlights•In vivo visualization of tau deposits has become possibly by PET radiotracers.•The tau tracer [18F]PI-2620 has high affinity to 4R-tau in 4-repeat tauopathies.•PCA identified 13 cerebral regions based on tau-PET SUVr z-scores in PSP and CBS.•Tau-PET topology correlates with symptomatology in 4-repeat tauopathies.•A precise knowledge of clinical signs is necessary when interpreting tau-PET.