DIGITAL SUBTRACTION ANGIOGRAPHY – Definition, Purpose, Indications, Factors Interference, Special Instructions, Client Preparation, Procedure, After Care and Disadvantages
Digital subtraction angiography (DSA) is a newer method of visualization of vascular structures. Less contrast medium is required, when compared with cerebral angiography. The image produced is made more distinct by the elimination of surrounding and interfering anatomical structures
DEFINITION
Digital subtraction angiography is a computer-based imaging method for visualization of extracranial, intracranial and vascular system by passing a catheter to certain veins and arteries
PURPOSE
- To identify the cause of transient ischemic attacks
- To assess intracranial tumors
- Preoperative and postoperative evaluation for vascular surgery
INDICATIONS
- Transient ischemic attacks
- Serial follow-up for clients with known carotid stenosis
- Intracranial tumors
- Postoperative aneurysm
- Extracranial and intracranial bypass procedure follow-up
- Dural venous sinuses
FACTORS INTERFERENCE
- This examination is very sensitive and even slight physical movements may cause poor imaging
- The art of swallowing results in unsatisfactory images
SPECIAL INSTRUCTIONS
- If an arterial pressure was performed, the affected extremity should be kept straight for 12-24 hours and the client must lie flat
- Do not raise the head of the bed because this can cause a strain the femoral puncture site
- Sudden onset of pain, numbness or tingling, greater degree of coolness and absent is informed to physician immediately
CLIENT PREPARATIONS
- Prepare the client physiologically and psychologically
- Explain the entire procedure thoroughly in simple words
- Instruct the client to make plenty of fluids to keep well hydrated
- No solid food for 2 hours before the procedure
- Inform the client that the entire procedure may take 30-45 minutes
- Obtain informed consent from the client
PROCEDURE
- Place the client comfortably on the treatment table
- Radiographic dye is injected into either the venous or the arterial circulation, but significantly less dye is necessary for arterial angiography
- X-ray film taken before and after dye injection is superimposed on each other all matching imaging are subtracted
- Thus, only the dye enhanced cerebral vessels are left for study and evaluation
- Digital subtraction angiography eliminates the shadows and distortions of bone or other material that sometimes block the viewing of the cerebral vessels
- After completion of the procedure, the catheter is removed
- Pressure is applied to the puncture site for several minutes and sterile dressing is applied
AFTER CARE
- Place the client comfortably on the bed
- Monitor vital signs and neurological status
- Check the catheter site for hemorrhage or hematoma formation
- Instruct the client to increase the fluid intake during the first 24 hours
- Observe for allergic reactions such as nausea, vomiting and urticaria
- Record the procedure in the nurse’s record
DISADVANTAGES
- The major disadvantage of digital subtraction angiography involves the client’s ability to remain motionless during the entire procedure. Even swallowing interferes significantly with the imaging process. This study cannot be done for uncooperative and children
