In Vivo Imaging of Blood-Brain Barrier Leakage Using a Contrast Agent in Patients With Cerebral Amyloid Angiopathy

BACKGROUND AND OBJECTIVES: Blood-brain barrier (BBB) leakage may be an early step in the pathophysiology of cerebral amyloid angiopathy (CAA), possibly preceding hemorrhages. This exploratory study measured BBB leakage in vivo at the level of the leptomeningeal and small parenchymal vessels in patients with probable CAA. We hypothesized that BBB leakage from leptomeningeal and cortical small vessels would be higher in patients with CAA compared with controls and that leakage would be associated with hemorrhagic manifestations of CAA, that is, cortical superficial siderosis (cSS) and lobar cerebral microbleeds (CMBs). METHODS: Patients with probable CAA without previous intracerebral hemorrhage and non-CAA patients with mild cognitive impairment from the memory clinic were recruited in this prospective observational exploratory study. Participants underwent 3T brain MRI with injection of a gadolinium-based contrast agent (Dotarem). Leakage from leptomeningeal vessels was assessed on postcontrast vs precontrast T2-fluid-attenuated inversion recovery as either focal or sulcal CSF enhancements. Dynamic contrast-enhanced scans were analyzed to quantify permeability-surface area product (PS): a measure of leakage from parenchymal small vessels. RESULTS: > 0.67). DISCUSSION: Leakage of gadolinium-based contrast agent through the BBB can be measured in vivo in CAA from the leptomeningeal vessels, and findings point to likely leakage from cortical small vessels as well. Leakage from leptomeningeal vessels was associated with cSS. Studies with follow-up data need to determine whether these measures could serve as a predictive biomarker in CAA.