Doppler-device Not known Quantification Cerebral microemboli during carotid artery endarterectomy and angioplasty with stenting Right to left shunt in cryptogenic stroke: TCD vs. TEE Author

Patent foramen ovale is frequently associated with embolic cerebrovascular accidents. The diagnosis of patent foramen ovale (PFO) is easier since the advent of transesophageal echocardiography but is invasive and does not allow to detect extracardiac RLS. Contrast transcranial Doppler ultrasound enables the detection of the passage of a contrast material injected into a peripheral vein to the cerebral circulation across an orifice which is most often a patent foramen ovale. It is subject to recent research to investigate the value of TCD in RLS diagnosis in contrast to other techniques. There is controversity about the optimal patient position for the detection of right-to-left shunt (RLS).