[Lymph node diagnosis with imaging methods. An overview with special reference to recent developments in the area of MR contrast media].

The main problem in current lymph node imaging is the lack of reliable criteria for differential diagnosis between benign and malignant nodes, the main criterion being size. To reliably opacify all lymph nodes in the body, an intravenous contrast agent is therefore necessary. Two new contrast agents for MRI seem promising: lymphotropic iron oxides and Gadolinium DTPA-PGM. After intravenous administration these agents accumulate in phagocytic cells of normal lymph nodes but are excluded from nodes in which phagocytic activity is replaced. While iron oxides are already in clinical studies, GD-DTPA-PGM is in preclinical studies. Both agents seem to significantly improve the differential diagnosis between benign and malignant lymph nodes irrespective of size.