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

Objective:SW2 is a new specific lymphatic contrast agent which is used in interstitial magnetic resonance lymphography. When injected subcutaneously through toe web of hind legs, SW2 could image lymphatics and lymph nodes efficiently. This study aims to explore the application value of the cervical lymphatic imaging in interstitial magnetic resonance lymphography using submucosal injection of Dextran-DTPA-Gd.Methods:The 0.2mL Dextran-DTPA-Gd (3.96mmol/L) was injected into the submucosa of the bilateral lingual margins in 12 New Zealand rabbits, and then massaged the injection site 30 seconds. MR images were obtained before injection and 10,15,20,25, 30,35,40,50,90minutes after injection by the 3D TOF CE-MRA sequence. The signal intensities of cervical lymph node were measured, the enhancing rates(E%) were calculated and the signal enhancing rates-time curve was drawn. The data was analyzed using SPSS 11.5 software package. Blood chemistry and blood routine were measured, and histopathologic examination of liver and kidneys was done before and 4w after the experiment.ResultsrThe cervical lymph nodes, the first and second lymphatics were strengthened significantly after injecting SW2, but the blood vessels were not enhanced at the same time. The enhancing rates of cervical lymph node reached the peak(344%) 20min.,and could get the best strengthening effect between 20min to 50min..After injecting 4h the contrast agent was excharged and the signal strength of the lymph nodes and lymphatics returned to nomal levels.There were obvious difference of the enhancing rates of cervical nodes in different time(P＜0.05). 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 in a week.Conclusion:The new type of specificity contrast agents SW2 could remarkable homogeneous enhancement the popliteal lymph node and lymphatic vessels.Its durationg is long. And MR lymphography could display both lymph nodes and lymphatic vessels clearly after subcutaneous injection of SW2.The contrast agent was specific for lymph nodes and lymphatics. The contrast agents has latency clinical value and is a good lymphatic enhancement tracer.