For various uses of TCD in stroke refer to Alexandrov, Cerebrovascular Ultrasound in Stroke Prevention and Treatment (2004).

There are many uses of TCD:

• Diagnosis of intracranial stenosis

• Diagnosis of acute occlusion

• Monitoring of acute thrombolytic therapy

• Vasoreactivity (vascular reserve) with carotid disease

• Emboli monitoring

• Vascular monitoring during surgery

• Detection of right-to-left shunt (RLS) (most commonly patent foramen ovale)

Procedure for right-to-left shunt detection

Based on European Society of Neurosonology and Cerebral Hemodynamics consensus, 1999.

Equipment

• TCD

• two normal saline bottles 15 cm3

• two 10 cm3 syringes

• flexible tubing

• three-way stopcock

Preparation

• The patient must be in the supine position, with the arm horizontal. An intravenous catheter (#18) is inserted into an antecubital vein (connected to a 250 ml bottle of physiologic solution by means of a flexible tube to maintain venous access).

• The right middle cerebral artery is traced by means of TCD (the examination is more sensitive if bilateral monitoring is used).

Procedure

• Two 10 ml (or 20 ml) syringes are prepared: one containing 9 ml of physiologic solution and the other containing 1 ml of air. By means of a three-way stopcock, the contents of both syringes are rapidly mixed until a homogeneous solution is obtained.

• The solution is rapidly injected in bolus form with the patient at rest. Inject with the syringe pointed superiorly so the bubbles aggregate at the top and are injected first.

• The MCA is monitored for 40–60 seconds.

The procedure is repeated with Valsalva maneuver

• The efficacy of the Valsalva maneuver must be ascertained beforehand through the reduction of the systolic flow velocity on MCA by at least one-third.

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