Table 1.

Evolution of the Boston diagnostic criteria for CAA-related cerebral hemorrhage [82-84]

	Boston 1.0	Boston 1.5	Boston 2.0
Definite CAA	The complete autopsy results confirmed that lobar, cortical or subcortical hemorrhage was found with severe vascular Aβ deposition on the premise of excluding other etiological diagnosis.	No change	No change
Probable CAA with supporting pathology	Clinical symptoms and pathological tissue or cortical biopsy confirmed that on the premise of excluding other etiological diagnosis, cerebral lobe, cortical or subcortical cerebral hemorrhage with a certain degree of vascular Aβ deposition.	No change	No change
Probable CAA	Clinical symptoms and MRI/CT confirmed that multiple cerebral hemorrhage (including cerebellar hemorrhage) limited to lobar, cortical or subcortical, age ≥55 years old, other diagnoses were excluded.	Clinical symptoms and MRI/CT confirmed that (strictly) multiple hemorrhage (including cerebellar hemorrhage) limited to lobar, cortical or subcortical or single lobar, cortical or subcortical cerebral hemorrhage and focal/diffuse cSS, age ≥55 years old, other diagnoses were excluded.	1. Main diagnostic criteria:
				1) Age ≥50 years old. Clinical manifestations: ICH, TFNE, cognitive impairment
				2) Imaging findings: there were more than 2 foci of frontal hemorrhage on T2*GRE: cerebral hemorrhage, CMBs and cSS, without any other deep lesions, and other diagnoses were excluded.
			2. Supporting evidence: severe CSO-PVS, multifocal hyperintensity distribution of frontal white matter
Possible CAA	Clinical symptoms and MRI/CT confirmed: multiple cerebral hemorrhage (including cerebellar hemorrhage) in single lobe, cortex or subcortex, age ≥55 years old, other diagnosis was excluded.	Clinical symptoms and MRI/CT confirmed multiple hemorrhage in a single lobe, cortex or subcortex (including cerebellar hemorrhage), focal/diffuse cSS, age ≥55 years old, excluding other diagnoses.	Deleted

CAA, cerebral amyloid angiopathy; Aβ, amyloid β; MRI, magnetic resonance imaging; CT, computed tomography; cSS, cortical superficial siderosis; ICH, intracerebral hemorrhage; TFNEs, transient focal neurological episodes; T2*GRE, T2*-weighted gradient recalled echo; CMBs, cerebral microbleeds; CSO-PVS, perivascular space in centrum semiovale.