Introduction: Arterial wall enhancement detected on vessel wall MRI (vwMRI) has been associated with increased stroke risk in the setting of intracranial atherosclerosis. Other pathologies affect the vessel wall, including cerebral amyloid angiopathy (CAA). CAA is secondary to Aβ vessel wall deposition resulting in microvessel leakage, microbleeds and ischemic stroke. Our goal was to determine if vwMRI could detect vessel wall inflammation and leptomeningeal contrast leakage in CAA, and if these are associated with recent infarction.
Methods: In this retrospective study, 28 vwMRI scans in 23 patients demonstrated probable CAA from 2015-16. Probable CAA was diagnosed by peripherally located microhemorrhages detected on susceptibility-weighted imaging. Vessel wall and leptomeningeal enhancement was determined using a validated pre and post contrast flow-suppressed T1-weighted sequence. Recent infarcts were detected by DTI trace (20 direction B2000). A mixed effects logistic regression model was used to determine the association of vessel wall or leptomeningeal enhancement with recent infarct in CAA patients, accounting for up to 3 scans per patient.
Results: In the 28 vwMRI scans, ischemic stroke was detected in 17 (61%), leptomeningeal enhancement in 13 (46%), and vessel wall enhancement in 14 (50%). The figure shows a representative patient with a recent infarct and biopsy-proven CAA with vessel wall enhancement (arrow) detected on vwMRI. Vessel wall enhancement was associated with recent infarct with an odds ratio (OR) = 10.8, p= 0.012. Leptomeningeal enhancement was associated with recent infarct with an OR = 3.8, p= 0.11.
Conclusions: Both vessel wall and leptomeningeal enhancement are present in CAA, though vessel wall enhancement is more associated with recent infarction. Larger, prospective studies may be needed to determine future stroke risk and additional risk factors predicting ischemic stroke in CAA.