A Harmonized Visual Reading Framework for Tau PET Staging in Alzheimer Disease.

A harmonized 5-class visual tau PET framework across 18F-MK-6240 and 18F-flortaucipir achieves excellent interrater agreement (κ = 0.77–0.85) and detects more early tau positivity.

• Why it matters: Binary, regulatory-approved visual reading emphasizes advanced disease, leaving early tau burden and patient stratification less consistently captured across tracers.
• What they did: In a prospective multicenter HEAD study (n = 681; ages 50–90; 9 North America/Europe sites), blinded clinicians visually staged tau into negative, low, moderate, high, and atypical using 18F-MK-6240 (n = 681), 18F-flortaucipir (n = 644), 18F-RO948 (n = 150), and 18F-PI-2620 (n = 149), with Aβ PET and MRI.
• The result: Compared with the regulatory-approved 18F-flortaucipir binary framework, the harmonized approach identified more tau-positive cognitively unimpaired participants (PR = 1.89; P = .001 for 18F-flortaucipir; PR = 2.73; P < .001 for 18F-MK-6240) and more mild cognitive impairment cases (PR = 1.23; P < .001; PR = 1.42; P < .001), while tau classes tracked stepwise worsening in cognition, Aβ burden, and plasma p-tau217.

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