**7. Conclusion**

TCD is a non-invasive ultrasound technique that allows for the assessment of cerebral blood flow velocity in real-time. It has emerged as an important diagnostic tool in the evaluation of cerebrovascular diseases such as aSAH and ischemic stroke. TCD can detect cerebral blood flow changes that can help guide clinical management and improve patient outcomes. TCD has been used to diagnose and monitor changes in cerebral blood flow velocity in stroke patients, and to detect vasospasm and DCI in aSAH patients. TCD can also guide treatment decisions in these patients. Further research is needed to determine the full extent of the utility of TCD in these conditions.
