In cortical regions, [18F]PI-2620-positive clusters of 4R tauopathy cases had higher R1 (all p < 0.05) and k2 & k2a (all p < 0.0001) values when compared to 3/4R tauopathy cases, suggesting a faster tracer delivery and efflux from the target in the presence of 4R tau (Figure 2(a)). Here, MAPT is linked to tauopathy.