Venous system

Published on 01/04/2015 by admin

Filed under Radiology

Last modified 01/04/2015

Print this page

This article have been viewed 1440 times

Chapter 10 Venous system

Peripheral Venography

Intravenous (i.v.) peripheral venography is an invasive procedure requiring i.v. injection of contrast medium and the use of ionizing radiation. Marked limb swelling can result in failure to cannulate a vein which precludes use of the technique. False-negative results do occur. It is still considered the gold standard for diagnosis of deep venous thrombosis, but is now only rarely performed.

LOWER LIMB

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

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. This 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.

Films

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.

CENTRAL VENOGRAPHY

SUPERIOR VENA CAVOGRAPHY

Indications

1. To demonstrate occlusion or stenosis of the central veins

2. As a preliminary examination in transvenous interventional techniques

3. Congenital abnormality of the venous system, e.g. left-sided superior vena cava.

Contrast medium

LOCM 370, 60 ml.

Equipment

Rapid serial radiography unit, or preferably a C-arm with digital subtraction angiography.

Patient preparation

Technique

1. The patient is supine

2. 18G butterfly needles are inserted into the median antecubital vein of both arms

3. Hand injections of contrast medium 30 ml per side, are made simultaneously, as rapidly as possible by two operators. The injection is recorded by rapid serial radiography (see ‘Films’ below). The film sequence is commenced after about two-thirds of the contrast medium has been injected.

N.B. If the study is to demonstrate a congenital abnormality, or on the rare occasion that the opacification obtained by the above method is too poor, a 5-F catheter with side holes, introduced by the Seldinger technique, may be used.

Films/images

Images are obtained at a rate of one per second for 10 s.

Aftercare

None, unless a catheter is used.

Complications

Due to the contrast medium

Related

A Guide to Radiological Procedures