Study Of The Dextran-DTPA-Gd At Rabbit Popliteal Fossa Lymph Node Metastasis From Thigh Transplanted Tumor With Interstitial Magnetic Resonance Lymphography

Objective:Ccording to the difference of endothelial cells linking between the lymphatic capillaries and capillaries, we have developed a new type of specificity contrast agents Dextran-DTPA-Gd, and to investigate the developing situation of the interstitial magnetic resonance lymphoid contrast agent Dextran-DTPA-Gd through the rabbit popliteal fossa lymph node metastasis from thigh VX2transplanted tumor injection to show targeting enhanced metastatic lymph nodes and lymphatics.In order to evaluate the posibility of targeted for lymph node and to study the head and neck lymphatic pathway. To further understand the metastatic pattern of head and neck cancer provide a new method.Methods:VX2tumor was transplanted to the right hind limb quadriceps of12healthy New Zealand rabbits and the left side as a contrast.8rabbits has homonymy popliteal lymph node metastasis after1month through3.0GE MRI and they were later injected with lymphatic targeting contrast agent Dextran-DTPA-Gd0.4ml (3.96×10-3mol/L) through bilateral hindlimb toe web respectively. Enhanced MR images were obtained with interval10,15,20,25,30,35,40,45,50,55,60min,2h,4h,24h. The signal intensities before and after enhancing were measured to calculate the enhancing rates (E%) of popliteal lymph node and draw popliteal lymph node signal intensity-time curves to observe the development of cancer metastasis lymph nodes and lymphatics and to compare the differences of interval sides. Routine and biochemical blood test were examined for the blood samples taken before and24h after the experiment. The white rabbits’livers and kidneys were taken24h after the experiment to perform pathologic examination.Results:Ten minutes after injected into the rabbit’s bilateral hindlimb toe web, we can see part of the hind lymphatic and popliteal lymph nodes were strengthened without blood vessels developing. The signal on the left reached a peak after35min with E%to315%, while the right side reached a peak with E%to285%after45min and would be undifferentiated with the surrounding tissues after24h. Statistical analysis was made to popliteal lymph node enhancement rate. It was considered statistically significant as long as P<0.05. At the same time, the tumor-side opliteal lymph node signal intensity was lower than the normal side, and it took a longer time to reach the peak. It manifested as coarse and irregular shape, lymphatic vessels tortuous dilated, lymphatic chain incomplete and newborn lymphatic capillaries seen around lymph nodes as a result of tumor infection. The routine and biochemical blood test, pathologic examination were normal. All of the animals in each group have no adverse reactions after subcutaneous injection and after interstitial MR lymphography.Conclusion:Dextran-DTPA-Gd is specific to lymphoid tissue development. It can well display regional lymphatic drainage out of shape and accurately distinguish the morphology between normal and cancer cells metastasis lymph nodes. It can targeting developing metastasis lymph nodes and lymphatic of rabbit lower limbs popliteal clearly.