Projection difference index in lymphographic diagnosis of lymph node metastases

The Projection Difference Index (Px%) of Wiljasalo for lymphographic diagnosis based on the hypothesis that normal nodes are flat while metastatic nodes are globular or grape-like was investigated in a material of 220 removed lymph nodes. The transverse diameters were measured on films exposed in four projections. The metastatic lymph nodes as a rule deviated from the globular or grape-like shape and doubt is therefore expressed about the diagnostic value of the Px%.