Venous Thrombosis/Deep Venous Thrombosis(DVT), Lower Extremities, Duplex Ultrasound


  • Leg pain of questionable aetiology
  • Tight, unilateral, swollen leg
  • Heaviness in the leg, or painful leg
  • Discolouration of the leg
  • Painful, red lump which may indicate a superficial venous thrombosis (SVT) to ascertain if the SVT has extended into the deep venous system
  • Question of pulmonary embolism
  • Surveillance of known DVT

Contraindications and limitations:

  • Extreme leg girth (obesity or extreme oedema)
  • Site trauma such as open wounds in the scanning area
  • Casts or dressings that cannot be removed
  • Patients that cannot be adequately positioned.

Patient preparation:

  • Eat breakfast, lunch or a snack within 3 hours prior to attending the ultrasound appointment.
  • Be well hydrated. Please ensure 500ml-1500ml of water has been consumed prior to the ultrasound, unless underlying medical condition require you to reduce your fluid intake. Please note: Coffee and tea are dehydrating; these drinks are not included in the 500-1500mls of water. WHY? Being hydrated increases the blood volumes which allows for improved visualisation of the veins plus, low blood sugar levels and dehydration can be associated with a vasovagal response (light headiness, or fainting), whilst standing. Nutrition and hydration can help reduce the risk of this occurring.
  • On the day of the ultrasound, refrain from applying oils or moisturisers to the lower limb


What to wear:

Loose-fitting clothes, for example; elasticated skirt/pants/shorts and a loose-fitting top.

Ultrasound study technique:

Ultrasound is a non-invasive diagnostic study. The patient will lie on a bed, with the head of the bed slightly elevated for comfort. The leg will be rotated slightly laterally, if the patient can tolerate this, with a pillow supporting the leg and hip joint. Ultrasound gel will be applied to the leg. An ultrasound probe will be run over the leg from the groin to the ankle. Moderate pressure, with the scanner head, will be applied to the limb, segmentally, to compress the veins. After the compressibility of the veins is determined, colour Doppler and spectral Doppler will be applied, to assess the blood flow. The sonographer may also assess the veins with the patient in the erect (standing) or sitting position. Images will be obtained, and the results documented on a worksheet.

NOTE: During the examination of the common femoral vein, in the groin, if there is ultrasound evidence or suspicion, of a more proximal thrombus, for example; thickened vein wall, the presence of occlusive or non-occlusive thrombus, or the loss of normal phasic, venous blood flow, the ultrasonographer may extend the ultrasound to the abdominal veins and IVC.

Ultrasound study time:

  • 20-30 minutes per leg.
  • Plus, an additional 20-30 minutes, if the assessment of the abdominal veins, is required (see note above)


A worksheet can be available, if requested. A formal written report will be available within 24 to 48 hours, following the ultrasound examination, Monday to Friday. If the ultrasound findings demonstrate pathology, which may require urgent attention, the referring Doctor will be notified ASAP following the completion of the ultrasound.