Microenhancement as a Biomarker for Cerebral Microbleed in Inflammatory Cerebral Amyloid Angiopathy: Insights From 3D T1 Black-Blood MR Imaging.

Objectives: Cerebral microbleeds (cMBs) are common imaging findings in conditions related to cerebral amyloid angiopathy (CAA). Blood-brain barrier (BBB) leakage is considered pivotal in their pathogenesis. This study investigates the potential role of cerebral microenhancement (cME) as an imaging biomarker on 3D T1 black-blood MRI (BB-MRI) for BBB rupture, predicting the formation of cMBs in inflammatory CAA variants.

Methods: A retrospective review was conducted on biopsy-confirmed cases of CAA-related inflammation (CAA-ri) and amyloid-beta-related angiitis (ABRA) from the UT Southwestern Medical Center's BB-MRI registry (2014-2022). Subjects underwent 3D T1 BB MRI and susceptibility-weighted imaging. The presence and progression of cMEs and cMBs were assessed.

Results: A total of 5 subjects (1 CAA-ri, 4 ABRA) were identified. Frequent cMEs on 3D T1 BB MRI scans preceded cMB formation, particularly in subjects with the ɛ4/4 genotype experiencing a refractory clinical course. Stable subjects had fewer cMEs and cMBs.

Discussion: The presence of cME before cMB suggests their potential as a biomarker for cMB formation. The findings align with the hypothesis that BBB rupture and focal inflammation are critical in cMB pathogenesis. Further validation of 3D T1 BB MRI as an assessment tool for cMB formation in inflammatory CAA based on clinicoradiologic diagnosis and noninflammatory CAA could enhance monitoring and treatment strategies.