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Transcranial Doppler (TCD) is a noninvasive ultrasonic technique that measures linear cerebral blood flow velocity (CBFV) and pulsatility index (PI) in the proximal portions of large intracranial arteries and represents physician stethoscope to the brain.

TCD ultrasonography also has a unique ability to detect emboli while they appear in cerebral vessels.


The demand for noninvasive, low risk, low-cost assessment of cerebral vessels will increase given multiple national public awareness campaigns. TCD ultrasonography currently is the diagnostic and monitoring technique of choice in both the outpatient and inpatient setting. There are several reasons why TCD examinations needed, among them:

  • The aging population will undoubtedly result in an increased incidence of chronic diseases, including coronary artery disease, heart failure, and stroke (by the year 2025 in the USA we’ll have 24.5% of all population will be 60+ years old)

  • Hospital/Private Practice can offer better treatment and more appropriate clinical care and further diagnostic testing for patients if TCD examinations can provide information about the presence or absence of CVD

  • Managed Care Contracts and Insurance careers could save money if they will utilize less expensive tests, like TCD ultrasonography vs. Neuroimaging modalities without jeopardizing the quality of health care and would save money on DRG’s and capitated contracts (HMO’s)

  • The use of TCD at hospital admission allows identification of patients with brain hypoperfusion due to the stroke, vasospasm after SAH/TBI and intracranial hypertension

  • In such high-risk patients, early TCD goal-directed therapy can restore normal cerebral perfusion and will help in reducing the extent of secondary brain injury

  • TCD represents an effective tool to monitor the effects of treatment and interventions

  • TCD test results contribute to the pharmacological management, further diagnostic testing and/or interventional treatment

  • Clinical value of TCD for Critical Care: Detect a Change from Baseline/Normal Values Early in the Course of Illness and Before Irreversible Damage Occurs

TCD is used principally in the evaluation and management of patients with CVD and onset (acute or subacute) of cerebral ischemia. Conventional and digital subtraction angiography (DSA), where available, constitutes the “reference standard” for evaluating patency and degree of stenosis in intracranial vessels. TCD studies have proven helpful in diagnosing and monitoring response to therapies and endovascular interventions for disordered cerebral circulation, and in determining prognosis for individual patients. In general, TCD is most useful when the clinical question pertains to large-vessel intracranial arteries. However, in some settings, TCD can detect indirect effects suggestive of proximal hemodynamic or distal obstructive lesions. It is well documented that TCD provides additional information that could not be obtained with neuroimaging modalities, like MRI/MRA or CT/CTA. Even DSA could be inconclusive if all relevant vessels are not fully imaged.  Based on the current experience it is possible to organize and provide the TCD service that could be performing all range of TCD studies, starting from the comprehensive TCD evaluation of patients with acute stroke and traumatic brain injury in Emergency Department, throughout the hospital wards, TCD monitoring in OR, ICUs, angiography suits, and finishing with TCD confirmation of brain death. 

TCD examinations could be utilized in outpatient settings, like neurology or cardiology outpatient clinics.

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