Micro-MRI improves the accuracy of clinical diagnosis in cerebral small vessel disease.

Even with postmortem pathological examination, only limited information is provided of the foci of clinical information. Cerebral small vessel disease, which is associated with ageing, dementia and stroke, highlights the difficulty in arriving at a definitive diagnosis of the lesions detected on radiological examination. We performed a radiological-pathological comparative study using MRI to examine small cerebral lesions. Four patients with small vessel disease lesions detected on MRI were studied. Exact pathological findings of MRI-detected lesions were revealed. The ischaemic lesion after 17 days from onset showed positivity for peroxiredoxin, cluster of differentiation 204 and glial fibrillary acidic protein, indicating sterile inflammation and neuroprotective reaction. Cortical microinfarcts beneath the cortical superficial siderosis were associated with inflammation from the superficial layer in a patient with cerebral amyloid angiopathy; in this patient, a bilinear track-like appearance of the cortical superficial siderosis on the MRI was compatible with iron deposition on the pia matter and within cortical layers II-III. An MRI-detected cerebral microbleed was revealed to be heterogeneous. An MRI-detected cerebral microbleed was revealed to be a venous angioma. Furthermore, a neuropathologically confirmed embolic cerebral microbleed was firstly detected using this method. Our results suggest that MRI-detected lobar cerebral microbleeds can be caused by non-cerebral amyloid angiopathy aetiologies, such as microembolism and venous angioma. Venous angioma and embolic microbleeds may mimic cerebral amyloid angiopathy markers on MRI. To clarify the clinical importance of these lesions, we should investigate their rate and frequency in a large cohort of healthy individuals and patients with cardiac risk factors. Thus, we provide evidence that micro-MRI improves the clinical diagnosis of small vessel diseases.