LAUSR

The history of how to diagnosis cerebral amyloid angiopathy (CAA) tells the story of the disease itself. CAA is defined by histopathology—deposition of β-amyloid in the cerebrovasculature—and through the 1980s the disorder was only diagnosed in patients with available brain tissue from hematoma evacuation, biopsy, or most commonly postmortem examination. Introduction of the imaging-based Boston criteria for diagnosis of CAA in the 1990s allowed a diagnosis of probable CAA in living patients with no available brain tissue and substantially moved the field from the pathologist’s realm to the clinicians. The Boston criteria for CAA have become the basis for clinical decision-making as well as a rapidly growing body of literature investigating the disease’s clinical manifestations, phenotypic spectrum, progression, and potential for disease-modifying therapy. The history of CAA diagnostic criteria also illustrates broader issues for other major central nervous system diseases. If the brain were as accessible to direct tissue examination during life as the blood or even the liver, diagnosis and staging of brain disorders such as cerebral small-vessel or neurodegenerative disease would be relatively straightforward and the state of clinical trials would presumably be more advanced. Given the relative inaccessibility of brain tissue, however, diagnostic approaches have needed to rely on indirect but nonetheless powerful methods such as magnetic resonance imaging (MRI). The current article will review the evolution and application of the Boston criteria, how the criteria have contributed to the search for CAA biomarkers, and future directions in this still evolving field.