 Transcranial doppler TCD is an established tool for monitoring flows in intracranial cerebral arteries. Its use is recommanded in the last guidelines on traumatic brain injury. The temporal bone window TBW is limited in evaluating flow in the anterior cerebral arteries ACA because of an unfavorable insonation angle. Thereby TCD could be unfit to detect a segmental lesion on the anterior cerebral arteries ACA. 