"One of the difficulties with Alzheimer's disease is that by the time all the clinical symptoms manifest and we can make a definitive diagnosis, too many neurons have died, making it essentially irreversible," said Jae Ho Sohn, a resident in the school's Department of Radiology and Biomedical Imaging and the study's lead researcher, in a statement.

For the study, published in Radiology, Sohn and his team fed a common type of brain scans to a machine-learning algorithm, and it learned to diagnose early-stage Alzheimer's disease about six years before a clinical diagnosis could be made. The AI's diagnostic skills could give doctors a much-needed headstart on treating the degenerative disease.

Sohn and his team focused on PET scans that monitored glucose levels across the brain, because glucose is the primary source of fuel for brain cells. Once the cells become diseased, they eventually stop using glucose, making it an important level to track. However, the changes are subtle—at least to the human eye.