An Experimental Study Of The New Specific Contrast Agent On Interstitial Magnetic Resonance Lymphography

Objective:This topic according to the difference of endothelial cells linking between the lymphatic capillaries and capillaries, we have developed a new type of specificity contrast agents SW2 and underwent the IMRLG examination. 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:All of the MR examinations were performed on a 3.0 GE MR.Twenty-fourhealth the New-Zealand white rabbits were randomized into two groups with 12 animals in each group.(1)The first group underwent the MRI examination,followed by subcutaneous injection each of 0.4ml(3.96 X 10-3mol/L) SW2 in the right legs. After half an hour the left legs were injection of 0.4ml (0.4998mol/l) contrast agents Gadopentetate Dimeglumine (Magnevist). And contrast scanning was performed at minutes 10,15,20,25,30,35,40.45,50,55,60 and 2,4,24 hours after injection.(2) The second group underwent the MRI examination,followed by subcutaneous injection of 0.2ml(3.96×10-3nol/L) SW2 in the right legs. At the same time the left legs were injection of 0.2ml(3.96×10-3mol/L) contrast agents Magnevist. All of animals contrast scanning was performed at minutes 10,15,20,25,30,35,40,45,50,55,60 and 2,4,24 hours after injection. Post-contrast MR images were obtained in the same imaging planes as pre-contrast images with identical scan parameters.The signal intensities of popliteal lymph node were measured on unenhanced images and enhanced ones.and the enhancing rates(E%) were calculated to draw the signal-time course curve. To compare the effects of two contrast agents,SW2 and Magnevist in magentic resonance lymphograghy. Routine and biochemical blood test were examined for the blood samples taken before and 24h after the experiment. The white rabbits'livers and kidneys were taken 4 weeks after the experiment to perform pathologic examination.Results:On enhanced images, two sets of the bilateral popliteal lymph node and lymphatic vessels showed remarkable homogeneous enhancement.After subcutaneous injection,SW2 didn't enter the blood, causing obvious homogeneous enhancement of the lymphatic vessels and popliteal lymph nodes. However, Magnevist quickly entered blood circulation to result in obvious enhancement of the anterior tibial vein and the urine. The lymphatic vessels and popliteal lymphnodes also homogeneous enhanced obviously.SW2 resulted in higher enhancement rate than Magnevist and the peak enhancement occurred at the Thirty minutes, whereas Magnevist showed the peak enhancement at the twenty minutes. There was obvious difference between them(P< 0.01). 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:The new type of specificity contrast agents SW2 remarkable homogeneous enhancement the popliteal lymph node and lymphatic vessels than Magnevist. Its duration is also longer than Magnevist. And MR lymphography could display both lymph nodes and lymphatic vessels clearly after subcutaneous injection of SW2. The new type of specificity contrast agents SW2 has specific for lymph nodes and lymphatics. The contrast agents has latency clinical value and is a good lymphatic enhancement tracer.