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The reflected ultrasound is received by the probe, transformed into an electric impulse as voltage, and sent to the engine for signal processing and conversion to an image on the screen. The depth reached by the ultrasound beam is dependent on the frequency of the probe used. The higher the frequency, the lesser the depth reached. [9]
Unlike arterial ultrasonography, venous ultrasonography is carried out with the probe in a transversal position, (perpendicular to the vein axis), displaying cross-sections of the veins. [4] All collateral veins are better detected this way, including perforator veins , but of most importance is the detection of venous thrombosis .
A duplex ultrasound (doppler ultrasonography and b-mode) can detect venous obstruction or valvular incompetence as the cause, and is used for planning venous ablation procedures, but it is not necessary in suspected venous insufficiency where surgical intervention is not indicated. [10] [6]
Venous ulcer is defined by the American Venous Forum as "a full-thickness defect of skin, most frequently in the ankle region, that fails to heal spontaneously and is sustained by chronic venous disease, based on venous duplex ultrasound testing." [1] Venous ulcers are wounds that are thought to occur due to improper functioning of venous ...
On duplex ultrasound, demonstration of echogenic material within the portal vein, complete or partial absence of colour flow in the portal vein, presence of collateral vessels around the portal vein or gall bladder that bypass the portal vein. [9] Portal vein thrombosis grading after Yerdel et al
Ultrasonography of deep venous thrombosis; Ultrasonography of chronic venous insufficiency of the legs; Duplex evaluation is usually done prior to any invasive testing or surgical procedure. [8] Ultrasound duplex scanning can provide additional information that may guide therapeutic decisions.
Patients are usually fitted with Class 3 (30-40mmHg) graduated compression stockings and/or bandages for up to 12 hours weeks. Duplex ultrasound is used during follow-up to assess the success of treatment, if there is a need for additional sclerotherapy or any deep vein thrombosis that has formed as an EHIT secondary to procedure.
Diagnosis can be made using ultrasound or laparoscopy testing. The condition can also be diagnosed with a venogram, CT scan, or an MRI. Ultrasound is the diagnostic tool most commonly used. [8] Some research has suggested that transvaginal duplex ultrasound is the best test for pelvic venous reflux. [11]