DOPPLER IMAGING

DOPPLER IMAGING – Definition, Indications, Purposes, Advantages, Types, Client Preparation, Equipment, Special Consideration, Procedure and After Care

Ultrasound technology provides information about the flow velocity of blood through cerebral vessels using non-invasive technique. A Doppler is placed externally over the vessel, where ultrasonic waves are generated and blood flow velocities are calculated

DEFINITION

Doppler imaging is a noninvasive diagnostic method to study the flow velocity of blood through cerebral vessels, specifically the circle of Willis

INDICATION

  • This procedure is used in the intensive care unit to monitor clients who have experienced cerebrovascular disorders, such as stroke, head trauma or subarachnoid hemorrhage
  • It can help detect intracranial stenosis, vasospasm and arteriovenous malfunction as well as assess collateral pathways

PURPOSE

  • To detect carotid artery disease such as atherosclerosis arterial occlusion
  • To detect vertebral artery disease such as stenosis or reversal of flow
  • To detect jugular vein disease such as thrombosis or recanalization

ADVANTAGES

  • It is a noninvasive procedure, which causes no pain
  • It is a safe procedure
  • It is relatively inexpensive
  • It has high accuracy

TYPES

  • Extracranial Doppler studies: extracranial Doppler studies are used as a routine screening. It is used monitor the intraluminal narrowing of the common and internal carotid arteries as a result of arteriosclerotic plaques or atheromata
  • Transcranial Doppler studies: transcranial Doppler studies monitor cerebral blood flow velocity through cranial windows or thinned areas of the skull. One such area, the most popular is the temporal bone

CLIENT PREPARATION

  • Prepare the client physiologically and psychologically
  • Explain the entire procedure in simple words
  • Inform the client not to move during the procedure

EQUIPMENT

  • Transcranial Doppler unit
  • Transducer with an attachment system
  • Terry cloth headband
  • Ultrasonic coupling gel
  • Tissues

SPECIAL CONSIDERATION

  • Velocity changes in the transcranial Doppler signal correlate with changes in cerebral blood flow. Parameter the most clearly reflects this changes in the mean velocity
  • Embolus appears as high-intensity transients that occur randomly during the cardiac cycle. Emboli make a distinctive clicking, chirping or plunking sound
  • Various screens can be stored on the system’s hard drive and can recall or printed
  • Before using the intracranial Doppler system, be sure to remove turban head dressing or thick dressings over the test site

PROCEDURE

  • Place the client comfortably on the examination table
  • A Doppler probe is placed externally over the vessel, where the ultrasonic waves are generated and blood flow velocities are calculated
  • As the diameter of the vessel changes, the velocity of the flow of the blood through the vessel changes
  • The Doppler probe represents the velocity of the blood flow
  • These data are amplified, a graphic and sound recording of the blood flow are produced
  • This procedure takes 15-45 minutes to complete

AFTER CARE

  • Check the vital signs
  • Document the entire procedure in nurse’s record
DOPPLER IMAGING – Definition, Indications, Purposes, Advantages, Types, Client Preparation, Equipment, Special Consideration, Procedure and After Care
DOPPLER IMAGING – Definition, Indications, Purposes, Advantages, Types, Client Preparation, Equipment, Special Consideration, Procedure and After Care

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