P3‐401: EXAMINING THE ABILITY OF A TAU SPATIAL SPREAD METRIC TO INDICATE DISEASE PROGRESSION COMPARED TO AN INTENSITY‐BASED APPROACH. (1st July 2006) - McCullough, Austin A.; Gordon, Brian A.; Christensen, Jon; Dincer, Aylin; Keefe, Sarah; Flores, Shaney; Hornbeck, Russ C.; Bateman, Randall J.; Morris, John C.; Ances, Beau M.; Benzinger, Tammie L.S.