Background and Purpose: Cerebral microbleed (CMB) in the lobar region is regarded as an image marker for cerebral amyloid angiopathy (CAA), but it is sometimes encountered in patients with intracerebral hemorrhage (ICH) owing to hypertension or other small vessel disease (SVD). Recently, enlarged perivascular space (EPVS) in white matter and deep region was suggested to be another potential marker for SVD. Knowledge of CMB location and EPVS in patients with ICH in relation to amyloid deposition might help us understand its heterogeneous pathophysiology.
Methods: Fifty-seven primary, spontaneous ICH patients underwent magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) to analyze the CMB, the EPVS in basal ganglia (BG) and centrum semiovale (CSO), and the overall white matter hyperintensity (WMH). 11C-Pittsburgh Compound B (PiB) positron emission tomography was also performed to measure the global amyloid deposition and was quantified as standardized uptake value ratio (SUVR) using cerebellum as the reference.
Results: Twenty-six patients with lobar ICH and 31 patients with deep ICH were included. Positive PiB scan (SUVR >1.13) was found in 37% of patients (11 lobar ICH, 10 deep ICH). Presence of lobar CMB was found in 65% of patients irrespective of PiB scan status (p=0.084), but PiB (+) had higher number of lobar CMB (14.6 ± 16.9 vs. 5.4± 10.1, p=0.014) compared with PiB (-) patients. In PiB (-) patients, the number of lobar CMB is positively correlated with the number of deep CMB (p<0.001, r=0.773). The presence of lobar CMB in PiB (-) patients is also associated with severe EPVS in BG (70% vs. 31%, p=0.042), but not in CSO (p=0.073).
Conclusions: Lobar CMB can be found in more than half of ICH patients irrespective of PiB scan status, but higher number of lobar CMB is seen in PiB (+) ICH patients. In PiB (-) patients, the presence of lobar CMB is associated with higher deep CMB number and EPVS in BG, suggesting the contribution of hypertensive angiopathy instead of amyloid angiopathy.