Vein Scan - Purpose, Procedure, Principle, Benefits, and Risks

What Is a Vein Scan?

A vein scan or a venous ultrasound is a specialized diagnostic test that is used to visualize the venous system of the body. This noninvasive test makes use of ultrasound to see and evaluate the veins and also the blood flow within them. A vein scan is most commonly performed in the lower extremities to look for blood clots or any obstruction in the vein. When a Doppler technique is added to this ultrasound, the movement of blood (speed and volume) within the vessels can also be evaluated. Hence this technique is also known as a venous duplex scan (duplex: two-mode, doppler, and B-mode ultrasound).

What Is the Purpose of a Vein Scan?

1. The vein scan procedure can be used throughout the body to check for any blood clots or obstructions in the veins. However, they have found more specific usage in the lower extremities.

2. A venous ultrasound is considered a first-line imaging modality in a condition known as deep vein thrombosis (DVT). DVT is a condition where blood clots are present in the veins of the legs. Patients would usually present with severe pain and non-specific swelling. It is vital to diagnose DVT; if untreated, there is a possibility of the clot getting dislodged and entering the circulatory system. From the circulatory system, they could reach the lungs resulting in a critical situation called pulmonary embolism. Hence, prompt diagnosis and timely intervention are of utmost importance in DVT.

3. This procedure is used to determine the cause of the varicose vein. The varicose vein is an enlarged superficial vein that is most often seen in the legs. Prolonged standing and increased walking are considered contributing factors to the varicose vein.

4. A vein scan can be used to identify the precise location of the vein for the placement of the needle or a catheter, thereby minimizing the damage to the adjacent nerve or vessel.

5. It is of great value in a coronary bypass procedure to map out the veins of legs or arms from where a vein graft can be taken.

6. It can also be used to examine the effectiveness of a graft used in dialysis and also the dialysis fistula, which is usually created.

7. It is used in a condition called May-Thurner syndrome, where the veins in the pelvis are affected. It is a congenital condition where the left iliac vein is compressed by an artery, thereby preventing proper blood flow and resulting in swelling in one leg.

8. In pediatric patients, it can be used to evaluate congenital malformations such as arteriovenous malformation and fistula.

9. To check for blood clots, obstruction, or narrowing of the vessel.

10. Tumors or any congenital abnormalities.

11. Increased or reduced blood flow in the veins.

12. To diagnose vascular diseases.

13. To monitor a vein recanalization procedure where a vein was reconstructed.

14. To monitor vein thrombectomy where a clot was removed.

How Should the Patients Prepare for a Vein Scan?

• Patients should wear comfortable clothes.

• They should remove all the jewelry and valuables before the procedure.

• Fasting for six to eight hours will be required only in case of an abdomen venous ultrasound.

• In other vein scan procedures, patients have no dietary restrictions.

What Is the Principle Used in a Vein Scan?

Ultrasound works on the principle of sound waves. The transducer sends high-frequency sound waves which are inaudible to the human ear, which upon striking certain structures within the body, bounce back as echoes. These echoes are then captured back again by the transducer and transmitted to the computer, where they are displayed as real-time images. The computer processes the image based on the amplitude, frequency, and time taken by the waves to return to the transducer. A duplex venous scan works on the same principle, just with the added effect of the Doppler technique. In Doppler, the movement of the blood results in an altered pitch of the reflected waves, which are then processed by the computer as images.

What Happens in the Vein Scan?

• Patients need to wear hospital gowns.

• Depending on the site to be examined, the patient may be asked to lie flat on the table or may be asked to stand or sit with legs hanging down.

• The radiologist would apply a clear gel on the site of examination.

• A small apparatus known as a transducer will be moved back and forth over the skin.

• While the transducer is moving, the radiologist may have to apply firm pressure to control the blood flow.

• The transducer would then transmit the echoed sound waves to the computer, where they would be converted into pictures or images.

• These images would be displayed in real-time on a screen for better assessment by the radiologist.

• In a Doppler study, the same transducer is used. The patients might hear a “whooshing” sound which is normal and made by the movement of the blood.

• Once the desired images are obtained, the gel will be cleaned, and patients will be asked to wait in the waiting room.

• The entire procedure may take roughly 30 to 45 minutes.

What Are the Instructions After a Vein Scan?

• Vein scan is a relatively simple and painless technique. Patients can carry on with their routine activities immediately.

What Parameters Are Assessed in a Vein Scan?

• Superficial or deep blood clots.

• Veins have one-way valves to prevent the backflow of blood. The valvular competency will be assessed.

• Quality of flow of blood (speed and volume).

• Compressibility of the veins.

What Are the Benefits and Risks of a Vein Scan Procedure?

Benefits:

• Noninvasive and painless as compared to venography, yet with an accurate diagnostic capability.

• Widely available and easy to use.

• Cost-effective.

• Quick and well tolerated by the patients.

• Safe as no radiation is used in this procedure.

• Best imaging modality for soft tissue such as veins.

Risks:

• Ultrasound has no known harmful effects.

• Some patients might feel faint or dizzy during the examination.

What Are the Limitations of a Vein Scan Procedure?

• Calf veins are small, and they are located deep below the skin; hence a vein scan may not prove very vital in calf veins.

Conclusion:

Though ultrasound is a simple procedure, it is a vital tool to assess soft tissues such as veins. A vein scan is considered the first choice diagnostic aid in patients suffering from chronic leg pain. It is a valuable noninvasive tool to detect a blood clot or any obstruction in the veins. A blood clot in the circulatory system could prove fatal; hence, early diagnosis is of utmost importance for a successful treatment and better prognosis for the patient.