Microbleeds in Postmortem Brains of Patients With Alzheimer Disease A T2*-weighted Gradient-Echo 7.0 T Magnetic Resonance Imaging Study

This study aims to determine the distribution and to quantify microbleeds (MBs) in postmortem brains of patients with Alzheimer disease (AD) on T-2*-weighted gradient-echo 7.0T magnetic resonance imaging. Twenty-eight AD brains were compared with 5 controls. The AD brains were subdivided further: 18 without and 10 with additional severe cerebral amyloid angiopathy (AD-CAA). The distribution and the number of cortical focal signal intensity losses, representing MBs, were assessed on coronal sections at the frontal, the central, and the occipital level of a cerebral hemisphere. MBs prevailed in the central sections (P = 0.005) of AD brains without CAA, whereas in AD-CAA brains, they were more frequent in all coronal sections (P <= 0.002). They prevailed in the deep cortical layers of the AD brains and of the controls (P <= 0.03). They were significantly increased in all cortical layers of the AD-CAA brains (P <= 0.04), compared with the controls. MBs prevalence in brains of AD patients had a different topographic distribution according to the absence or presence of severe CAA.