Venography
The process of radiography of the vein is venography. Venography has been largely replaced by Ultrasonography, because Ultrasonography is noninvasive, more readily available processing technique. Both are almost equally accurate for detecting DVT. If the patient is not satisfied or suspicious about the result of Ultrasonography results, then he/she must opt Venography for confirmation. The patient allergic to the contrast agent should not go for Venography.
If symptoms and signs suggest Pulmonary Embolism then additional imaging such as CT pulmonary angiography and ventilation/perfusion [V/Q] scanning should be performed to confirm between differential diagnosis.