Patients with antiphospholipid syndrome (APS) are prone to thromboembolism. So far, the only predictive parameters for further complications are their number in patient's history and perhaps the titre of aPL. Derived from clinical investigation of stroke and obvious analogies between cerebrovascular ischemia (CVI) in patients with carotid artery disease (CAD) and patients with APS, a novel non-invasive method is introduced using transcranial Doppler (TCD) long-term monitoring to detect high energy ultrasonic signals (so called ‘microemboli’) in the cerebral vasculature. In patients with CAD, these microemboli proved to correlate with past and impending symptoms of CVI permitting therapeutic stratification by their detectability. In SLE and APS, this technique enabled identification of very similar signals in cerebral bloodstream of APS patients. Microemboli were highly associated with the history of CVI and the titre of aPL. Detection of microemboli offers new possibilities in risk estimation, therapeutic stratification and in studying pathophysiology of APS.