[citation needed] The risk of deep vein thrombosis can be estimated by Wells score.

[2] Serial follow-up the ultrasound exam is not necessary after an initially complete, normal study in individuals with DVT symptoms who have suspected pulmonary embolism and nondiagnostic ventilation/perfusion scans .

Nevertheless, when the examiner needs to show the head thrombus in a printout, the probe will be presented parallel to the vein axis.

[4] A very recently formed thrombus is not very solid, it will have a low echogenicity, and will be seen as a black area in the gray-scale image and will be hardly visible.

[10][11][12] Doppler ultrasonography of venous blood flow that correlates with respiration can be diagnostic of the absence of deep vein thrombosis.