Phlebography is a subspecialty of angiography and is an invasive imaging procedure used to visualize the veins. In this procedure, a contrast agent containing iodine is injected into the vein area to be examined, and parallel radiographs are taken to document the flow of the contrast agent over time. Since the administration of contrast medium and the puncture of the corresponding vein is an invasive method, the patient must be informed in detail about the risks and side effects. X-ray radiation is also a burden, so it makes sense to prefer noninvasive procedures such as Doppler sonography (ultrasound examination).
Indications (areas of application)
- Varicosis – varicose veins; when the great or small saphenous vein is affected, the clinical picture is called truncal varicosis
- Before venous surgery to document the status of the veins and varicose veins.
- Recurrent varicose veins (repeated varicose veins)
- Phlebothrombosis – venous thrombosis
- Unclear findings in sonography (ultrasound).
- Suspicion of pulmonary embolism – pulmonary vessel occlusion, which can be caused by a carried thrombosis from the legs.
- Before thrombectomy – surgical removal of a thrombus.
- Before thrombolysis – drug dissolution of a thrombus.
- Postthrombotic syndrome – clinical picture after expired thrombosis.
- Suspicion of recurrence
- Course or status control after extensive phlebothrombosis.
The procedure
Phlebography can be performed in a variety of ways, resulting in several procedures. In the following, the ascending phlebography according to Hach is described. This is the method of choice today and is used primarily for thrombosis diagnosis (diagnosis of a blood clot occluding the deep veins, for example). During the examination, the patient is placed on an examination table tilted at a 45 degree angle. At the same time, the patient supports himself with his arms so that his legs are in a comfortable hanging position. A warm foot bath may be used in preparation so that the veins of the foot are well exposed. A tourniquet is now placed supramalleolary (above the ankle). Approximately 50-100 ml of contrast medium is then injected via a foot vein. In arm phlebography, the contrast medium is injected analogously into a dorsal hand vein or into the cubital vein. The contrast medium enters the deep venous system directly through the tourniquet. This process can be accelerated by manual compression. Since the venous valves are of particular interest in this examination, it is important to show them in a closed state on the X-ray. This is the only way to assess a damaged venous valve or reflux (backflow of blood). For this purpose, the patient is asked to perform the so-called Valsalva press test without tensing the muscles of the extremities. The abdominal squeeze increases venous pressure in the veins. If the venous valves are intact, they close and prevent the blood from flowing back to the lower extremities. If, for example, a truncal varicosis is present, the contrast medium flows back from the deep veins into the superficial veins. Thus, the point of insufficiency can be precisely localized. X-rays are taken in two planes as target images of the vascular region and over time. Phlebography is divided into several phases:
- Empty phase – The contrast medium has not yet reached the lumen of the veins to be examined.
- Antegrade filling phase – The veins are visualized by the flow of contrast medium.
- Washout phase – In this phase, the concentration of the contrast agent decreases, and alternating careful Valsalva maneuvers and manual compression allow the finest structures to be visualized.
Other variants of phlebography are presented in the following section: Cavography involves imaging the superior or inferior vena cava. Here, the contrast medium is administered either through the veins of both arms (superior vena cava) or through the femoral vein (inferior vena cava). This procedure is rarely used nowadays, as the examination is usually replaced by computed tomography. Another method is retrograde phlebography, in which the contrast medium is injected directly into the femoral vein (great femoral vein).In this case, truncal varicosis can be diagnosed if the contrast medium flows retrogradely (i.e., back) through the damaged venous valves into the lower legs. Since the invasiveness of puncturing the femoral vein is very high, the method is rarely used. Varicography is a form of phlebography in which diluted contrast medium is applied to smaller varices (varicose veins). This method is also rarely indicated. If phlebography does not yield satisfactory findings, other measures such as CT phlebography (computed tomographic examination of the veins with intravenous administration of contrast medium) or MRI phlebography (magnetic resonance phlebography with or without contrast medium) may be performed.
