Isolated calf venous thrombosis: diagnosis with compression US

[Venous echo Doppler: a future standard test in the diagnosis of thrombosis of the lower limbs?]

Duplex ultrasound imaging provides both an ultrasound picture of the tissue being explored and the sound of the flow speed in a particular area. Colour Doppler imaging gives colour codes for the different flow rates. Venous pathology is always investigated, with ultrasound, on both sides, at the iliac and caval, femoral, and foreleg levels. For the latter, excellent equipment and patient position are required. Ultrasound criteria of deep venous thrombosis (DVT) are the incompressibility of the vein being investigated, and detection of the thrombosis with the ultrasound probe. Doppler criteria are asymmetric spontaneous flows, the loss of their respiratory rhythm, and the lack of flow induced by contraction of muscle. The colour Doppler draws provides the contours of a partial or floating thrombus. Compared with phlebography, ultrasound imaging has a sensitivity and specificity of 96%. Colour Doppler imaging is even more accurate: both sensitivity and specificity increase to 100%. The limitations of ultrasound are: its dependence on the investigator, the difficulty of making the diagnosis of recurring DVT when there already are previous sequellae, obesity, intra-abdominal gas, skin lesions or inflammatory oedema. Phlebography remains necessary in 5% of cases. The advantages of this technique are its non invasiveness, excellent diagnostic performance, low cost, and the possibility of diagnosing another cause, whether responsible for the clinical signs or not. It is indicated for the diagnosis of DVT, routine screening in patients at risk, and the early and late follow-up of patients. Today, ultrasound imaging should always be carried out before other investigations.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasound evaluation of deep venous thrombosis

Ultrasonography has achieved the role of the contemporary diagnostic tool for the assessment of DVT. Routine use of venography to assess for lower extremity clot is very difficult to justify. Long-term follow-up of patients has provided sufficient documentation that ultrasonography can successfully supplant the venogram. Only with regard to calf vein thrombosis is there still uncertainty about the need to occasionally rely on venography. Radiologists must become cognizant of the capabilities of ultrasonography and facile in its interpretation. Performance of this test should be available in every institution. The nonradiological literature is replete with articles documenting the use of venous ultrasonography and encouraging its routine use for venous clot evaluation.