Background In a subset of patients with cerebral amyloid angiopathy (CAA) vascular inflammation is also present. Two pathologic subtypes have been described: one with perivascular inflammation (CAA-related inflammation or CAA-RI), and the second with a vasculitic transmural inflammatory infiltrate (Aβ-related angiitis or ABRA).
Objectives To investigated the role of imaging in differentiating CAA with and without inflammation.
Methods 54 patients had pathological evidence of CAA with or without inflammation at the Mayo Clinic (Rochester, MN) over 25 years. All available pathologic specimens were re-reviewed by one neuropathologist (CG). Neuroimaging findings (brain CT and/or MRI) at the time of diagnosis were available in all patients. All neuroradiologic findings were reviewed by a neuroradiologist (JM) who was blinded to the histologic diagnosis. Clinical data were also collected.
Results The Table shows the radiologic findings at presentation of the 27 patients with CAA without inflammation, 22 with ABRA and 5 with CAA-RI. Strictly leptomeningeal disease and leptomeningeal process with infiltrative white matter were significantly more frequent radiological presentations in patients with ABRA and CAA-RI compared to those with CAA (10/27, 37% versus 1/27, 3.7%, p=0.005; and 11/27, 40.7% versus 1/27, 3.7%, p=0.002, respectively), while lobar hemorrhage was more frequent in patients with CAA (18/27, 66.7% versus 2/27, 7.4%, p<0.0001). Globally, leptomeningeal involvement at presentation was present in 77.8% (21/27) of patients with ABRA + CAA-RI and in only in 7.4% (2/27) of patients with CAA (p<0.0001).
Conclusions Leptomeningeal enhancement at MRI may enable differentiation between CAA with and without inflammation. Leptomeningeal enhancement associated with lobar infiltrative white matter T2 hyperintensity's also helps differentiate these entities from the more common infiltrating low-grade gliomas.
Disclosure of Interest None declared