Amyloid-related imaging abnormalities (ARIA) are MRI findings that emerged as a major safety issue in anti-amyloid monoclonal antibody trials for Alzheimer's disease.[1][2] ARIA is usually divided into ARIA-E, which reflects vasogenic edema or sulcal effusions, and ARIA-H, which includes microhemorrhages and superficial siderosis.[1:1][3]
ARIA-E appears as parenchymal edema or sulcal effusion on MRI and is the subtype most strongly associated with symptomatic presentations such as headache, confusion, visual symptoms, or focal neurologic complaints.[1:2][2:1] The edema is typically vasogenic in nature, reflecting increased vascular permeability rather than true inflammatory changes.
Imaging characteristics include:
ARIA-H refers to hemosiderin-related findings including microhemorrhages and superficial siderosis. It is often asymptomatic but clinically important because it reflects vascular fragility and may alter risk-benefit decisions for continued anti-amyloid treatment.[1:4][3:2]
Imaging features include:
The leading model is that vascular amyloid burden, vessel-wall injury, and therapy-driven amyloid mobilization interact to increase vascular permeability and hemorrhagic risk.[1:5][2:2][4:1] This is why ARIA is often discussed along a continuum with cerebral amyloid angiopathy.[4:2]
Proposed mechanisms include:
Most cases are detected on protocol MRI rather than by symptoms.[1:9][3:6] Standard monitoring includes:
Management typically follows a severity-based protocol:
Corticosteroids (e.g., dexamethasone, methylprednisolone) are sometimes used in symptomatic cases to reduce edema and inflammation.[4:6]
Patients presenting with symptoms may require:
ARIA represents one of the central constraints on anti-amyloid treatment deployment:
ARIA matters across pages about lecanemab, donanemab, aducanumab, and broader amyloid immunotherapy vaccines for Alzheimer's disease, because it is one of the central constraints on anti-amyloid treatment deployment.
This section highlights recent publications relevant to this disease.
Antibody-based nanoparticles in Alzheimer's disease: Innovations in diagnosis and therapy. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Amyloid-related imaging abnormalities (ARIA) in Alzheimer's immunotherapy: a framework and challenges for global surveillance strategies. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Regulatory, clinical, and post-marketing challenges of lecanemab for Alzheimer's disease: insights from real-world data. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
The TREM2 agonistic antibody AL002 in early Alzheimer's disease: a phase 2 randomized trial. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Relationship between APOE Genotype Status and Imaging Features in Patients with Alzheimer Disease Being Considered for Antiamyloid β Therapy. ↩︎