Venous system

Methods of imaging the venous system

• 1.

  Contrast venography

• 2.

  Ultrasound (US)

• 3.

  Impedance plethysmography

• 4.

  Radionuclide imaging

• 5.

  Computed tomography (CT)

• 6.

  Magnetic resonance imaging (MRI).

Method

Intravenous venography.

Indications

• 1.

  Deep venous thrombosis

• 2.

  To demonstrate incompetent perforating veins (Doppler ultrasound is preferable)

• 3.

  Oedema of unknown cause

• 4.

  Congenital abnormality of the venous system.

Contraindications

Local sepsis.

Contrast medium

Low osmolar contrast material (LOCM) 240.

Equipment

• 1.

  Fluoroscopy unit with spot film device

• 2.

  Tilting radiography table.

Patient preparation

The leg should be elevated overnight to lessen oedema if leg swelling is severe.

Technique

• 1.

  The patient is supine and tilted 40° head up, to delay the transit time of the contrast medium.

• 2.

  A tourniquet is applied tightly just above the ankle to occlude the superficial venous system. The compression may also occlude the anterior tibial veins, and so their absence should not automatically be interpreted as due to venous thrombosis.

• 3.

  A 19G butterfly needle (smaller if necessary) is inserted into a vein on the dorsum of the foot. If the needle is too near the ankle, the contrast medium may bypass the deep veins and so give the impression of deep venous occlusion.

• 4.

  40 ml of contrast medium is injected by hand. The first series of spot films is then taken.

• 5.

  A further 20 ml bolus is injected quickly whilst the patient performs a Valsalva manoeuvre to delay the transit of contrast medium into the upper thigh and pelvic veins. The patient is tilted quickly into a slightly head down position and the Valsalva manoeuvre is relaxed. Alternatively, if the patient is unable to comply, direct manual pressure over the femoral vein whilst the table is being tilted into the head-down position will achieve the same effect. Films are taken 2–3 s after releasing pressure.

• 6.

  At the end of the procedure the needle should be flushed with 0.9% saline to lessen the chance of phlebitis due to contrast medium.

Images

Collimated to include all veins:

• 1.

  Anterior posterior (AP) of calf

• 2.

  Both obliques of calf (foot internally and externally rotated)

• 3.

  AP of popliteal, common femoral and iliac veins.

Aftercare

The limb should be exercised.

Complications

Method

Intravenous venography.

Indications

• 1.

  Oedema

• 2.

  To demonstrate the site of venous occlusion or stenosis

• 3.

  Superior vena cava obstruction.

Contrast medium

LOCM 300 mg I ml ^–1 .

Equipment

Fluoroscopy unit with spot film device.

Patient preparation

None.

Technique

For i.v. venography:

• 1.

  The patient is supine

• 2.

  An 18G butterfly needle is inserted into the median cubital vein at the elbow. The cephalic vein is not used, as this bypasses the axillary vein

• 3.

  Spot films are taken of the region of interest during a hand injection of 30 ml of contrast medium. Alternatively a digital subtraction angiographic run can be performed at 1 frame sec ⁻¹ .

Aftercare

None.

Complications