Changes in lymph node size induced by lymphography

Although the contraction of normal lymph nodes after lymphography has been measured the enlargment caused by lymphography has not. In this study the lengths and widths of 25 radiologically normal nodes were measured in five patients who had a second lymphogram carried out when these nodes were still outlined by contrast medium from the first lymphogram. If the mean length after the second lymphogram is taken as 100% then the mean length 24 h earlier measured 82%, and if the mean volume after the second lymphogram is taken as 100% then the mean volume 24 h earlier was 49%. These substantial increases are similar to the reductions which have been reported in some previous papers and are probably due to distension of lymph node sinuses by oily contrast medium. It is obviously important that changes in lymph node size which are induced by lymphography itself be taken into account when follow-up films and repeat lymphograms are used to assess the response of lymph nodes to treatment.