Since the 2021 FDA approval of the first monoclonal antibody (MAB) therapy for Alzheimer's disease (AD), treatment has progressed from symptom management to targeting and reducing amyloid β plaque burden. While these therapies offer hope of altering the disease course, they come with risks, such as amyloid-related imaging abnormalities (ARIA), which include ARIA-E (edema and effusion) and ARIA-H (hemorrhage). This report details the case of a 64-year-old woman undergoing donanemab treatment who developed severe ARIA, characterized by extensive vasogenic edema and multiple microhemorrhages. The increasing use of MABs necessitates heightened awareness and expertise among emergency radiologists to identify findings of ARIA effectively, ensuring timely and appropriate care for patients undergoing these novel therapies.