The 3D Ultrasound: New Strategy in the Diagnosis of Deep Venous Thrombosis (DVT) and of the Residual Vein Obstruction (RVO)

Introduction, Objectives, and/or Purpose: Clinical trials evidenced that the presence of ultrasound identified residual venous obstruction (RVO) on follow-up scanning may be associated with an elevate risk of recurrence, thus providing a potential tool to help in the determination of the optimal duration of anticoagulation therapy. The major problem is the criteria for determining re-canalization of a thrombosed vein. Ultrasound criteria for quantifying residual venous thrombosis are not widely used. This quantification is allowed by using 3D ultrasound.

Methods: Patients with first episode of documented idiopathic and provoked DVT were eligible for the study. C-US of the affected leg was performed and images were obtained with trasversal sections (the study was performed in orthostasis). For the quantification of the grade of thrombosis we have to do a trasversal study, evaluating each frame (for example every 2 millimeters) and we define the region of interest in the affected vein. The next step is to select free vascular area, where is possible the ematic circulation. At the end of the process, the program shows a percentual value of the thrombus. Patients were followed every months for a year.

Results: We evaluate 50 patients affected by DVT with 3D ultrasound. The range of occlusion goes from 30% to the 100%. Patients underwent follow-up after 1, 3, 6 and 12 months. 40 patients had a progressive reduction of thrombosis during follow – up. 5 patients had recurrence of the pathology, with an increased occlusion. 5 patients showed a reduction of the grade of thrombosis after 6 and 12 months.

Conclusion(s): Our results suggest that 3D ultrasound is very important and useful for evaluating the features of a DVT and RVO of the lower limb.
We acknowledge that the results of our study need to be evaluated with some caution, but this ability is important in driving a management strategy for the prevention of recurrences and the selection of a DVT patient population that may benefit from a shirt period of anticoagulation.