It's known as the long goodbye, but Alzheimer's disease takes a similarly long time to diagnose. Confirmation of whether a person truly had the disease is not possible until an autopsy of brain tissue is conducted. An international coalition of experts from France to Japan is trying to change that, calling for the use of new imaging techniques to scan the brain while the patient is still alive, and examination of cerebrospinal fluid, recently found to carry markers that signal the disease. Earlier diagnosis can mean better treatment.