Cortical microinfarcts in patients with multiple lobar microbleeds on 3 T MRI

The pathogenesis of cortical microinfarcts (CMIs) is considered to be heterogeneous including cerebral small vessel disease (SVD) such as hypertensive vasculopathy (HV) and cerebral amyloid angiopathy (CAA). Recent advances in MRI have enabled the detection of CMIs in vivo. To investigate the characteristics of CMIs in advanced cerebral SVD, we performed a retrospective analysis of 85 patients with cognitive impairment who had multiple lobar cerebral microbleeds (CMBs) on 3 T MRI. Among them, 41 (48.2%) patients were classified into the strictly lobar CMB group (i.e. probable-CAA group), and 44 (51.8%) patients were classified into the non-lobar with lobar CMBs group (i.e. mix-CMBs group). The relationship between CMIs and CMBs, cortical superficial siderosis (cSS) and white matter hyperintensity was evaluated. Nine of the 41 (22.0%) patients with probable-CAA had a total of 19 CMIs, while 12 of the 44 (27.3%) patients with mix-CMBs had a total of 38 CMIs. In the probable-CAA group, the presence of CMIs was significantly associated with the presence of cSS (p < 0.001). In addition, a close spatial association between CMIs and cSS was observed. On the contrary, in the mix-CMB group, the presence of CMIs was significantly associated with the number of lobar CMBs in the frontal lobe (p = 0.034). Our results suggest that CMIs in the probable-CAA may be attributable to more severe CAA, while CMIs in the mix-CMBs indicate an advanced HV, especially when observed with more numerous lobar CMBs.