Diagnosis of a Non-Invasive Ultrasound of the Lower Extremity
Duplex ultrasound is a combined ultrasound of two different types:
- B-mode (or brightness mode) ultrasound
- Doppler flow detection ultrasound, either as pulsed or continuous ultrasound waves
Regular ultrasound renders images of structures within the leg and Doppler ultrasound, using the same scanning transducer, reflects high frequency sound waves off of red blood cells in motion. Duplex ultrasound is used for identifying
- Blood clots in the deep veins of the legs
- Circulation impairment: Such as arterial obstruction or venous stasis
- Venous insufficiency (impaired venous valves): Which can lead to stasis
- Arterial abnormalities: Such as occlusion, eripheral arterial disease, aneurysms, or stenosis
Deep Vein Thrombosis (DVT) Diagnosis and Testing
The most common symptom of deep vein thrombosis is swelling (edema) of the leg. It is usually unilateral, but may be bilateral. A tape measure is used to document the circumference of the calf or thigh and compare it to the non-involved leg.
Pain and warmth are frequently associated symptoms. DVT can be suspected on clinical grounds if these signs and symptoms occur, along with tenderness upon squeezing the leg. For establishing the diagnosis, ultrasound is the diagnostic modality of choice.
Peripheral Venous Disease (PVD) Diagnosis and Testing
PVD of the lower leg is the most common vascular disorder. It encompasses venous dilation/varicosities and venous reflux/venous valve insufficiency.
Complications of PVD aid in its clinical diagnosis and include acute and chronic ulcerations, local infection, and sepsis. Diagnosis is based on clinical signs and symptoms and ultrasound.
Peripheral Artery Disease (PAD) Diagnosis and Testing
Claudication is a symptom that presents as muscle pain with activity, indicating that the extra oxygen demand of muscle actions is not being met. PAD is the accumulation of plaques that can narrow or block the arterial blood supply, leading to claudication, ischemia, or necrosis.
Symptoms are often similar to those of deep vein thrombosis or thrombophlebitis, and ultrasound is used to differentiate PAD from DVT. Diagnosis via duplex ultrasound can identify arterial disease, from the femoral artery, popliteal, and lower branches up to and including the higher aortoiliac vessels.
Blood work to assess coagulation, glucose, liver function, blood count, etc., are not particularly useful in diagnosing vascular disease, but can serve as a clue for its underlying cause.