CLINICAL AND RADIOLOGICAL FINDINGS IN PATIENTS WITH PATHOLOGICALLY CONFIRMED CAA

Cerebral amyloid angiopathy (CAA) is frequently seen on pathological examination. However, the clinical and radiological features of pathologically confirmed CAA are not well known. Therefore we conducted this case series evaluating the clinical and radiological manifestation of CAA in patients with pathologically confirmed CAA. We searched the Dutch Brain Bank for patients from the Amsterdam Dementia Cohort with pathology confirmed CAA between 2005 and 2015 and available brain MRI. We included seven patients who had undergone a diagnostic work-up at our memory clinic. At pathological examination, two types of CAA were distinguished: CAA type 1 including capillary CAA (capCAA) and CAA type 2 without capCAA. We reviewed the clinical charts for symptoms of CAA, including cognitive decline, amyloid spells (operationalized as transient focal neurological deficits or atypical changes in consciousness), and intracranial haemorrhage (ICH), and we re-evaluated the brain MRI images. Three patients had CAA type 1 (CAA1) and four patients CAA type 2. All patients had a clinical dementia diagnosis. A clinical diagnosis of CAA was made in only one patient. The other clinical diagnoses were Alzheimer's disease (AD, n=5) and mixed dementia (n=1). These clinical diagnoses were pathologically confirmed, and in the AD and mixed dementia patients additional CAA pathology was established. Amyloid spells were seen in all patients with CAA type 1 and in only one patient with CAA type 2. MRI features of CAA (microbleeds (MB, n=3), cortical superficial siderosis (cSS, n=2)) were observed solely in patients with amyloid spells. Two patients with CAA type 1 had MB on MRI at presentation and one patient with type 1 showed cSS on follow-up MRI. One patient with CAA type 2 had MB, cSS and amyloid-related imaging abnormalities with edema and effusion (ARIA-E) on MRI and died of an ICH, confirmed on CT-scan. None of the lesions classified as MB on MRI could be confirmed by pathological examination (table 1). Amyloid spells are frequently seen in patients with CAA type 1. The typical radiological features of CAA (ICH, MB, and cSS) are not present in all pathology proven CAA patients and do not always correspond to pathology findings.