Spontaneous and Drug-Induced Amyloid-Related Imaging Abnormalities: Overlaps, Divergences, and Clinical Implications Across a Continuum Between Alzheimer’s Disease and Cerebral Amyloid Angiopathy

BACKGROUND: Amyloid-related imaging abnormalities (ARIA) have gained significance in the context of anti-amyloid therapies (AATs), exhibiting clinical and radiological manifestations that overlap with Cerebral Amyloid Angiopathy-related inflammation (CAA-ri). This review aims to elucidate the similarities and differences between spontaneous (sARIA) and drug-induced ARIA (dARIA). METHODS: We conducted a narrative review comparing sARIA and dARIA, focusing on their underlying mechanisms, clinical presentations, and implications for diagnosis and treatment. RESULTS: Both sARIA and dARIA are characterized by similar pathophysiological mechanisms involving amyloid deposits and neuroinflammation. Notably, ARIA can manifest as ARIA-E (edema) or ARIA-H (hemorrhage), with varying incidence rates in clinical trials. The review highlights that while sARIA occurs independently from treatment, dARIA is associated with AAT and can lead to significant symptomatic presentations. CONCLUSIONS: Understanding the continuum between sARIA and dARIA is crucial for improving diagnostic criteria, risk stratification, and therapeutic approaches. The proposed unified framework emphasizes the need for consensus in managing these conditions and advancing future research in amyloid-related diseases.