[Pelvic lymph node groups in computed tomography. Topographic atlas]

This atlas was prepared to facilitate the diagnosis of lymph mode enlargement in the pelvic region and to improve topographic diagnosis. Fifty computed tomographies were performed after lymphography using centimetric pelvic slices in order to select eight levels for reference. A statistical analysis was conducted to establish a diagram of the mean number of lymph nodes on the right and left side for each level. A table was established indicating the mean number and standard deviation for each group of nodes for the 8 different levels. In addition, a control slice (chosen among 50) accounts for the morphology of the iliac vessels, of the lymph nodes and psoas muscle most frequently encountered at each level. The distribution of the groups of nodes shows why interpretation can be difficult, particularly at vessel bifucations and confluents. Precise morphology based on effective opacification, especially in the pelvic area, is required for positive and especially topographic diagnosis. Finally, the description of the medial border of the psoas muscle and its close relations with certain groups of lymph nodes can cause some problems because of the similar densities. The atlas is of great help here.