Abstract Details

Title Illusion Of Infarction : Amyloid-related Imaging Abnormalities Mimicking Posterior Circulation Stroke

Topic Aging, Dementia, and Behavioral Neurology

Presentation(s) P2 - Poster Session 2 (11:45 AM-12:45 PM)

Poster/Presentation
Number 12-010

Objective N/A

Background Amyloid-related imaging abnormalities (ARIA) are MRI findings associated with anti-amyloid therapy (AAT) in Alzheimer’s disease. ARIA arises from vascular inflammation and increased permeability, resulting in vasogenic edema (ARIA-E) or microhemorrhage/siderosis (ARIA-H). Most often asymptomatic, ARIA can present with acute onset headache, vision changes and gait impairment, mimicking subacute infarction on CT, posing diagnostic challenges.

Design/Methods Case report

Results A 78-year-old woman with hypertension and mild cognitive impairment due to Alzheimer’s pathology presented with 2 days of visual disturbance, reading difficulty, headache, and unsteady gait, three weeks after starting lecanemab. Pre-infusion MRI showed moderate white matter disease and two microhemorrhages; she was heterozygous for ApoE gene (3/4). On examination, she had right homonymous hemianopia (NIHSS 2) with elevated blood pressure. CT demonstrated left parieto-occipital hypodensity, and CTA revealed high-grade stenosis of a left posterior cerebral artery (PCA) branch, raising concern for subacute infarct. Aspirin and permissive hypertension were initiated. MRI instead showed left occipital, parietal, and temporal, sulcal hyperintensity and enhancement, with slight right occipital edema, and a new punctate focus of susceptibility, consistent with moderate ARIA-E and mild ARIA-H. Aspirin was discontinued, blood pressure lowered, and she received three days of IV methylprednisolone followed by prednisone taper. Hemianopia resolved within 3 days. Lecanemab was withheld. Follow-up MRI at 1 month showed decreased edema without new hemorrhage. At 2 months, neuropsychological testing revealed new visuospatial and visual learning deficits.

Conclusions

This case highlights that careful identification of vasogenic edema that crosses vascular territories is crucial to differentiate ARIA from stroke. Risk factors include ApoE4 genotype, baseline microhemorrhages, elevated blood pressure, and early treatment phase. Recognition is essential as treatment differs from ischemic stroke, involving corticosteroids, AAT cessation, and MRI surveillance. ARIA may result in lasting functional impairment. Anticoagulation is contraindicated due to bleeding risk, while safety of antiplatelet agents remains uncertain.

Authors/Disclosures
Ameya Kale, MBBS (Capital Area Health Consortium) PRESENTER	Dr. Kale has nothing to disclose.
Stephanie Lontok, MD (University of Connecticut)	Dr. Lontok has nothing to disclose.
Melisha Budhathoki, MD	Dr. Budhathoki has nothing to disclose.
Alia Tewari, MD	Dr. Tewari has nothing to disclose.
Pooja Jethwani, MBBS	Ms. Jethwani has nothing to disclose.
Priya Narwal, MD (UConn health)	Dr. Narwal has nothing to disclose.

��ɫ��

��ɫ��