Deep venous thrombosis (DVT) is a venous reflux disorder caused by abnormal blood coagulation
in the deep vein, which usually occurs in the lower extremities. DVT is common in patients
with limb immobilization (such as after major orthopedic surgery), severe trauma, tumor, coma
or long-term bedridden patients. After thrombosis, venous valve function is often destroyed,
causing lower limb swelling, ulcers and other congestive diseases, affecting the quality of
life of patients; thrombus shedding is also easy to cause pulmonary embolism, serious cases
can lead to sudden death.
In the process of thrombosis, the components of thrombus are different in different stages.
in the acute stage of thrombosis, the consumption of blood fibroses is less, mainly in the
thrombolytic therapy of activating plasminogen; in the subacute and chronic phase of
thrombosis, the consumption of fibrinolytic enzyme is more, anticoagulant therapy is needed
to prolong the clotting time. Therefore, defining the staging of thrombus is the key to make
a reasonable treatment plan and improve the therapeutic effect of DVT. The guidelines
recommend that for patients with moderate or high likelihood of DVT, if two consecutive
ultrasound examinations are negative, further X-ray venography, CT venography or magnetic
resonance venous thrombosis direct imaging are recommended. Among them, magnetic resonance
thrombus direct imaging depends on the content of methemoglobin in the body and will not
produce radiation to the human body. it can not only accurately judge the thrombus in the
pelvic and inferior vena cava, but also show the details of the changes in the vein wall or
lumen. Therefore, magnetic resonance thrombus direct imaging has a certain potential in the
differential diagnosis of acute, subacute and old thrombus. In this study, we will use
magnetic resonance thrombus direct imaging to stage and judge the efficacy of drug treatment,
in order to provide help for clinic.