Evaluation of some new diagnostic modalities for deep venous thrombosis

ABSTRACT

The aim of this work is to evaluate some new diagnostic modalities; D-dimer test, Duplex imaging and MR venography; for Deep Venous Thrombosis [DVT]. Thirty patients were included in this study with clinically suspected Dm. Full history taking and thorough clinical examination together with routine, Laboratory investigation, resting ECG, Trans- thoracic Echo-Doppler Murex D-dimer test and Duplex imaging were done for all patients. MR venography was done only for the 16 cases with the clinical pretest intermediate probability for DVT. The results of the present study showed that 20 cases showed positive duplex, 7 with popliteal, 7 fern oral and 6 cases with femoral and popliteal DVT. 19 cases showed positive D-dimer test Vs 11 with negative test. The 16 cases subjected to MR venography showed results coincide with same findings as Duplex apart from 3 cases in which soleal and ilia1 DVT not detected by Duplex study. Conclusion: From the results, it was found that Duplex ultrasonography is now considered the diagnostic modality of choice in evaluation of the venous system of lower limbs. Because of its safety, accuracy, high specificity, sensitivity, and its availability, all these makes it a modality of choice. D-dimer test is specific degradation product of fibrin, in our study and other studies have shown its high sensitivity moderate specificity and high negative predictive value for suspected deep vein thrombosis. Its value varies from, one study to another according to the type of D-dimer assay used in the study. When D-dimer test combined with clinical pretest probability, its negative predictive value is markedly increased up to 100%. MR venography and Duplex sonography have been found to be identical for evaluation 01 DVT in venous system as regard of popliteal and femoral veins, but it is superior to Duplex study in evaluating venous system of the pelvis and iliac veins. Its availability, lack of operator experience and its cost limit its application. Recommendation Duplex ultrasound is the diagnostic modality of choice for DVT of lower limbs and MR venography is preferable only in selected cases. D-dimer test when combined with clinical probability is a good negative test which can reduced the need for Duplex imaging