Color Doppler Ultrasound And Infrared Thermal Imaging Technology Evaluate Lower Limbs Of Deep Vein Thrombosis

Part One Study on modeling of acute deep venous thrombosis in rabbitsObjective To establish a model of deep venous thrombosis(DVT) in rabbits for evaluating its feasibility and stability, and meanwhile for detecting imaging features of DVT with the application of CDU, contrast-enhanced ultrasound and infrared thermography.Methods Examining the posterior limbs of rabbit by CDU and infrared thermography before operation, then to make records of normal femoral vein Doppler flow maps and thermography. Animal models of venous thrombosis were made by blocking venous return flow with a vascular clamp temporarily, injuring the vascular wall, and injecting thrombin in the distal vein. Then fixed the hip and knee joints of the experimental sides in the flectional position with plaster, and control legs treated with sham surgery. 48h later the femoral veins on both sides were examined by CDU, contrast-enhanced ultrasound, infrared thermography and pathological test.Results 48h later all the rabbits survived, the CDU showed that both femoral veins were virtually anechoic, however the experimental side couldn't be compressed and no flow was detected, the control side was just the reverse. The thermography showed that the temperature of the experimental side was higher than that of the control. The contrast-enhanced ultrasound showed that there was no microbubble or filling defect in the experimental side.Finally the animals were sacrificed and the femoral veins of both sides were taken out of for pathological examination. The experimental side was filled with acute venous thrombosis which had not adhesion on the wall, but no thrombosis occurred in the control side.Conclusions The modeling method of DVT in rabbits is simple and reliable. It's also valuable for detecting thrombosis by using the technique of CDU, contrast-enhanced ultrasound and infrared thermography. Part Two Value of color doppler ultrasound in Venous Thrombosis of the Lower LimbsObjective To study the features of CDU in patients with DVT and evaluate its use . Methods Review the findings of CDU of 80 cases with DVT retrospectively and summarize the imaging features.Results The imaging features of DVT were that hypoecho or hyperechoic masses were seen in the lumen. The probe can not be pressurized lumen occlusion. Thin blood flow or no blood flow was observed in Color Doppler. Slow velocity was detected or the velocity was not changed with deep breath in Pulse Doppler. DVT typically occurred in the old who at the age of 60-80 years, the most common site of venous thrombosis was the left lower limb. The CDU could decide the staging system of venous thrombosis by detecting vascular diameter, lumen echo, wall thickness and function of valve.Conclusions CDU is the first choice to detect and follow up DVT for its sensibility and reliability. Part Three Value of Infrared Thermography in Clinical Patients with Suspect DVTObjective At present the CDU is the first choice to detect DVT for its non-invasion, radiationless,high-resolution and repetition. However it always takes a long time to examine both lower limbs, so it does not satisfy the need for screening plenty of clinical patients with suspect DVT. According to the result that we have learnt the imaging features of DVT in infrared thermography (see also from part one), and now for further study we will discuss its value in clinical patients with suspect DVT comparing with the CDU .Methods The 98 patients with suspect DVT accepted examinations respectively by the CDU and infrared thermography which were operated by two doctors, they didn't know the other's processes and results. Make sure that the double blind test carried through almost at the same time (within 0.5h). Finally compared results of infrared thermography with those of CDU by rank sum test, to evaluate the sensitivity, specificity, false positive rate, false negative rate and diagnose accordance rate of infrared thermography.Results There were 58 patients with DVT detected by the CDU, and 62 by infrared thermography. The sensitivity, specificity, false positive rate, false negative rate and diagnose accordance rate of infrared thermography was 79.3%, 60%, 20.6%, 40% and 71.4% respectively. It about took 5-10min by the infrared thermography on each patient.Conclusions It proved that the technique of infrared thermography had qualitative diagnosis value. We expect that it can apply in screening plenty of clinical patients with suspect DVT and following up efficacy.