In the present study,we have performed a multiscale computational study involving moleculardocking, molecular dynamics, free energy calculations, and QM fragmentationcalculations to understand the binding profiles of tau tracer AV-1451and its potential use for diagnosis of AD, CTE, and PiD tauopathies.Our computational study reveals that different affinity binding sitesexist for AV-1451 in the tau fibrils associated with different tauopathies.The binding affinity of this tracer toward different tau fibrils goesin this order: PiD > AD > CTE. The gene discussed is MAPT; the disease is tauopathy.