Leg VenographyThis is a featured page


Introduction

A leg venogram is a radiographic study of the deep veins of the legs and Inferior vena cava following the administration of a contrast medium.
NB:This procedure, once commonly performed in radiology departments, has now been completely replaced by ultrasound imaging.(compression technique and colour Doppler flow) . Duplex sonography (US) has become the imaging modality of choice, because of its simplicity and high sensitivity and specificity, especially in the femoropopliteal region.
Ultrasound should always be the imaging modality of choice, as there are no needles, no radiation, no IV contrast and when performed by a Sonographer is a highly sensitive test. There may be limitations in visulalising the calf veins due to oedema and obesity.

Indications

  • Deep vein thrombosis (DVT) is a common medical condition with a wide range of manifestations that range from an asymptomatic state to a classic symptomatic DVT, with important sequelae of pulmonary embolism, chronic venous insufficiency, and postphlebitic syndrome.
  • (DVT) is a common clinical problem that complicates many medical and surgical disorders It can cause morbidity in itself due to acute pain and swelling of the affected limb, and it may also cause structural damage to the valves of the deep veins that results in the postphlebitic syndrome.
  • If not recognized, deep venous thrombi can extend and embolize to the pulmonary arterial circulation. Pulmonary embolism can cause sudden death or, if nonfatal, result in shortness of breath and chest discomfort
  • Clinical examination is insensitive, and objective tests are required for the diagnosis
  • Leg venography is performed almost exclusively to exclude deep vein thrombosis (DVT)
    • DVT is a difficult Diagnosis to make on the basis of clinical findings alone
      • Up to half of patients with signs and symptoms suggestive of DVT do not actually have DVT
      • Conversly, many patients who do have DVT will not manifest the typical symptoms of leg swelling and calf pain
http://www.thaivir.org/thai/download/ContrastVenographyPG.pdf
  • Symptoms of lower extremity DVT will usually present in one of two ways.
  • The first is with symptoms of calf-popliteal vein DVT. Most patients with acute DVT will initially develop symptoms of pain and swelling in the calf of one leg
  • The symptoms tend to increase with ambulation and improve with rest. There may be associated increased warmth, redness, and tenderness of the calf area.
  • On average, a patient's symptoms will persist for about 7 days during that time, symptoms usually worsen.
  • The pain and swelling may become more severe and progress proximally up the leg to the popliteal fossa and medial thigh

Contraindications
  • non-consent by patient to procedure
  • contrast or iodine allergy
  • pregnancy (pregnancy test compulsory for women of child-bearing age in some centres)
  • impaired renal function (check creatinine if recent test available). A creatanine level greater than 180 micromols/litre is a contraindication
  • bleeding disorders, blood thinning medications , anticoagulants (heparin, warfrin, aspirin)[ check INR if available]
  • morbid obesity can mitigate against successful foot vein access
  • diabetic patients on metformin
  • severe asthma

Anatomy



leg veins
leg veinswww.health.com
The superficial veins consist of the long and short saphenous trunks and their tributaries. Multiple arcades (commonly three) join the greater and lesser saphenous systems. Other superficial veins may bypass the saphenous veins to drain more proximallly into the gluteal veins or the veins of the lower abdomen. The perforating veins penetrate through the deep fascia to connect the deep veins with the superficial veins. They are present from foot to groin.( more common in the calf)

  • Lower extremity venous anatomy can be broadly divided into three components:
  • Superficial veins
  • Deep veins
  • Perforating veins
  • The superficial system includes the small (SSV) & greater saphenous veins (GSV)
  • The greater saphenous vein continues along the medial aspect of the thigh and drains into the common femoral vein (CFV) at the saphenofemoral junction (SFJ).
  • The deep system is more complex that the superficial system
  • Common femoral vein
  • Femoral vein (prevoiusly known as Superficial femoral vein often duplicated)
  • Deep femoral vein( drains thigh previously known as profunda femoris vein)
  • Popliteal vein
  • Three paired veins drain the calf
    • – The anterior tibial veins ATV (lateral)
    • – The peroneal veins PV(medial and deep)
    • – And the posterior tibial veins PTV(Medial)
These veins run parallel to the tibial arteries of the same names

The muscular veins (venous sinuses of the calf muscles which dont have valves)
  • Medial and lateral gastrocnemius veins
  • Medial and lateral soleal veins

  • The tibial veins drain into the popliteal vein which inturn forms the femoral vein (FV) at the adductor canal.
  • The deep femoral vein (DFV) drains the thigh muscles and joins with the FV to form the CFV
  • The superficial and deep systems are joined by a series of perforating veins
  • Venous blood flows from the superficial to the deep system, aided by the presence of bicuspid valves in the veins of both systems, in a normal competent system.

quoted from •SCVIR Syllabus “Venous Interventions” in
Chap:Diagnosis of Deep Venous Thrombosis (p190)
by Jeanne M. Laberg, M.D. & Peter W. Callen, M.D
.

Preparation

  • patient identification (3 Cs- correct patient, correct side, correct procedure)
  • Patient should be wearing a hospital gown; pants,socks and shoes removed
  • consent form
  • no diet restrictions (some centres suggest fast from solids for 4 - 6 hours prior to procedure)
  • collect relevant previous imaging for ease of access prior to procedure
  • Radiologist may require a bucket of hot water to place patient foot in to encourage dilation of peripheral foot veins
  • low level sedation may be required for extremely anxious patients
  • If the patient's lower limb is very oedematus/swollen, elevation of the limb prior to the procedure for 8 hours may assist in needle access to the leg veins
  • 'Emla' local anaesthetic cream can be applied to the dorsum of the patient's foot 90 minutes prior to the procedure to reduce the pain associated with the needle insertion.

Tray Setup

1 21 guage 3/4 inch butterfly needle
3 25 ml syringes
1 drawing up canula
1 swab
1 tape
1 20 ml normal saline in 25 ml syringe
2 tourniquet


Radiographic Technique
Preparation
  • Leg venography can be performed 'blind' using serial exposures on a 35 x 43 cm (17 x 14 inch) cassette. This is an effective technique that was performed for many years prior to Ultrasound imaging for DVT. A preferable technique is to use fluoroscopy and spot film imaging (DSI). The advantage of using fluoroscopy is that you can take spot film at the point of maximum opacification of the venous anatomy.
  • If you are using a plain film technique, check whether your protocol requires preliminary/scout films
  • There is considerable advantage in using an X-ray machine with a tilting table (some would consider it essential)
  • If the X-ray table/fluoroscopy unit has a removable footplate, this must be in place for the acquisition sequences.
  • If you are using a fluoroscopy unit, ensure that the image intensifier can travel low enough to image the patient's ankle. A block may need to be placed under the unaffected leg to ensure that the patient's ankle can be included on the initial images.
  • The patient is positioned supine on the X-ray/fluoroscopy table with a block under the unaffected leg to ensure that the affected leg is not weightbearing.
  • The table is tilted feet down 30 - 45 degrees
  • If you are using a fluoroscopy unit, select the maximum field size
  • If you are using a plain film technique, it is very useful to have a second radiographer changing the exposure facts as you image up the patient's leg
  • Tourniquets are positioned above the knee and ankle on the side of interest. When these tourniquets are tightened, the contrast will be blocked from entering the superficial veins forcing it into the deep veins.
  • Non-ionic contrast medium should be drawn up ready to use. It is preferable to have the contrast warmed for ease of injection (reduces viscosity of contrast). Contrast should not be warmed above body temperature.
  • warn the patient that they may experience a flushing sensation and/or a metallic taste in their mouth

Vein Cannulation
  • The radiologist will clean the dorsum of the patient's foot with antiseptic skin prep solution.
  • The ankle tourniquet is tightened and the radiologist will place a 19 or 21 gauge butterfly needle into a vein on the dorsum of the foot. A 5ml syringe filled with saline will be used to check the needle tip is in position (exclude extravisation)
  • a warm flannel applied to the dorsum of the patient's foot can induce peripheral venous dilation
  • the median vein relative to the great toe frequently provides a suitable vein for injection
  • The dorsum of your foot is a very sensitive site to have a needle inserted. Warn the patient that it is an uncomfortable experience.
  • Successful cannulation of a vein on the dorsum of the foot can be very difficult. The following can techniques can improve success rates
    • tilt the X-ray table head up
    • soak a flannel in warm-hot water and place on the dorsum of the patient's foot (Do not burn patient!)
    • tapping with fingers on a vein of interest
    • place foot in a bucket of hot water (do not burn patient)
    • ensure the ankle tourniquet is tight
  • When the dorsal foot vein is successfully cannulated, ensure the ankle and knee tourniquets are tight.

Butterfly Needlebutterfly needle
Imaging
  • If you are using a non-fluoroscopic technique ("plain film") it is prudent to have all of the cassettes in the X-ray room with you (protected from scatter radiation). Alternatively, a second radiographer can be running in and out of the room supplying you with cassettes (this technique avoids accidental radiation fog of images)
  • 50 mls of non-ionic contrast medium (diluted with 25mls normal saline to make 75 mls total) is injected into the dorsal foot vein and AP and both oblique views of the lower leg veins are taken. These images should include the patient's ankle joint. A lateral view may also be taken.
  • The ankle torniquet must be tight for the initial imaging of the calf veins. The tourniquet will occlude the superficial but not the deep veins. The contrast material injected into the superficial vein in the foot will be forced by the tourniquet to be directed into the deep veins from the superficial veins through perforating veins
  • The ankle tourniquet can be removed after all 75 mls of contrast/saline is injected
  • The knee tourniquet is removed and AP imaging centred on the patients knee and femur are taken. (release tourniquet just before exposing the knee)
  • The final image(s) is centred on the patient's hip on the side of interest. The patients leg is raised and calf squeezed to facilitate improved flow of contrast medium into the patient's inferior vena cava. The patient should be instructed to hold their breath (+ valsalva manoeuvre) for the IVC image.
  • A subtraction technique can be used with digital fluoroscopy
  • If you are using a fluoroscopy unit, the Radiologist may be imaging and the radiographer may be injecting. If you are injecting, check the injection site continuously to ensure that there is no extravisation of contrast into the soft tissues of the patient's foot.


Technique Tips
  • All adjacent images should overlap (no missed anatomy)
  • It is very easy to image too quickly when using a plain film technique- don't change cassettes so quickly that you beat the contrast bolus up the leg
  • repeat injection and imaging may be required (ie a second run)
  • Don't use too low a kVp- you want to be able to penetrate the contrast-filled veins
  • If the patient is unsteady, it may be prudent to apply a buckyband or other support around the patients chest/abdomen
  • If the patient is post hip surgery, examine the affected leg first
  • some radiologists prefer 50 mls of non-ionic contrast (370 mg/ml) diluted with 25 mls to make a total of 75 mls. This is injected through three 25ml syringes.
  • In an adult patient with normal renal function, total contrast media injected should be less that 200 mls of 370 mg/ml.

Images

venogram venogram
venogram venogram
venogram venogram
Note the flow void simulating a narrowing of the femoral vein
venogram venogram
venogram venogram


Pathology

  • A vein containing thrombus will either appear as an occluded vein or may have a 'train track' appearance cause by the contrast running around the thrombus

DVT
source: Mosby 2003 in www.elcamino.edu/faculty/mcolunga/RT%20255/Venography%20&%20Lymphography.ppt

This venogram image demonstrates extensive DVT of the deep veins. Note numerous filling defects.


Aftercare
  • Patient should be observed for 1 hour to ensure no adverse reaction to contrast media or bleeding from injection site
  • increase fluid intake

Complications

  • Venogram induced DVT
  • contrast allergic reaction (anaphylaxis)
  • extravisation of contrast media
  • nausea/vomiting
  • pulmonary embolus
  • injection site local infection

...back to the Wikiradiography home page
... back to the Applied Radiography home page




AndyC
AndyC
Latest page update: made by AndyC , Feb 7 2010, 8:37 PM EST (about this update About This Update AndyC Moved from: Radiography - AndyC

No content added or deleted.

- complete history)
More Info: links to this page
There are no threads for this page.  Be the first to start a new thread.

Related Content

  (what's this?Related ContentThanks to keyword tags, links to related pages and threads are added to the bottom of your pages. Up to 15 links are shown, determined by matching tags and by how recently the content was updated; keeping the most current at the top. Share your feedback on WikiFoundry Central.)