Differentiation of tumor-bearing from benign lymph nodes with SPIO-enhanced MR imaging / 中华放射学杂志

ABSTRACT

Objective To investigate the value of superparamagnetic iron oxide particles(SPIO) in MR imaging for differentiation of metastatic lymph nodes from normal or reactively hyperplastic lymph nodes. Methods For the time course study,10 ?mol Fe of SPIO per extremity was administered to 6 animals, and images were obtained before and 1 h to 48 h after administration. Reactively hyperplastic lymph node model was established in 6 animals by injection of egg yolk emulsion, and tumor bearing lymph node model was established in another 6 rabbits. MR images of the popliteal lymph nodes were obtained before and 12 h after subcutaneous administration of SPIO. Imaging results were analyzed and correlated with pathological findings. Results In unenhanced images, the signal intensity of tumor free and metastatic lymph nodes did not differ significantly. After administration of SPIO, a significant signal intensity loss occurred in the tumor free lymph node, and the maximal loss occurred at 12 h, and the signal intensity reduced by 49%,28%,59%, and 89% on T 1WI, T 2WI, PDWI, and T  2WI, respectively at 48 h( P =0.000). However, the signal intensity of the metastatic lymph nodes remained unchanged. Conclusion MR imaging after subcutaneous administration of SPIO help to differentiate metastatic from normal or reactively hyperplastic lymph nodes.