Answer
The Boston Cerebral Amyloid Angiopathy Group has elaborated guidelines for the diagnosis of cerebral amyloid angiopathy (CAA) associated with intracranial hemorrhage (ICH). Four levels of certainty in the diagnosis of CAA are considered: definite, probable with supporting pathologic evidence, probable, and possible. The first 3 require that no other cause of hemorrhage has been identified. The levels are characterized as follows:
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Definite CAA - Full postmortem examination reveals lobar, cortical, or corticosubcortical hemorrhage and evidence of severe CAA
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Probable CAA with supporting pathologic evidence - The clinical data and pathologic tissue (evacuated hematoma or cortical biopsy specimen) demonstrate a hemorrhage with the aforementioned characteristics and some degree of vascular amyloid deposition
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Probable CAA - Clinical data and magnetic resonance imaging (MRI) findings (in the absence of a pathologic specimen) demonstrate multiple hematomas in a patient older than 60 years
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Possible CAA - This is considered if the patient is older than 60 years and clinical and MRI data reveal a single lobar, cortical, or corticosubcortical hemorrhage without another cause; multiple hemorrhages with a possible, but not definite, cause; or some hemorrhage in an atypical location
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MRI Brain GRE 3.0 TeslaTop: Multiple scattered microbleeds in multiple vascular territories in patient with hyperhomocysteinemia and methylene-tetrahydrofolate reductase mutation. Middle: Acute parenchymal hematoma with typical appearance of right occipital microbleed and left parietal chronic microhemorrhage.Bottom: Microbleeds involving multiple lobes. Chronic hemorrhage in the left parietal lobe with typical slit-like appearance.
