Dignitätsbeurteilung von abdominellen Lymphadenopathien im Power-Doppler-Ultraschall

AIMS: Recent studies report higher accuracy of power Doppler sonography than for computertomography and magnet resonance imaging in the differentiation of benign from malignant peripheral superficial lymphadenopathy. To our knowledge a study of abdominal lymph nodes in power Doppler sonography has not been done so far. This study was undertaken to find out, if power Doppler sonography can differentiate benign from malignant abdominal lymph nodes on the basis of defined vascular patterns. METHOD: We evaluated retrospectively 88 coloured pictures of abdominal lymph nodes (39 benign lymph nodes, 24 malignant lymphomas, 25 lymph node metastasis) done in the power-Doppler-modus. The goal was, to find out, if benign and malignant abdominal lymph nodes can be differentiated in power Doppler sonography on the basis of 9 defined vascular patterns. The pictures were also evaluated by three other investigators on the basis the same 9 defined vascular patterns. We compared their results to assess the interobserver-variance. RESULTS: Three vascular patterns showed a significantly higher appearance in malignant than in benign lymph nodes (p< 0,05): aberrant vessel (p=0,025, positive predictive value 77%, specifity 87%, sensitivity 34%), avascular focus (p=0,001, positive predictive value 86%, specifity 92%, sensitivity 38%) and subcapsular vessel (p=0,001, positive predictive value 100%, specifity 100%, sensitivity 24%). Hiliar vessel showed a significantly higher appearance in benign lymph nodes (p=0,038, positive predictive value 66,7%, specifity 87,8%, sensitivity 30,8%). Hypervascularisation showed a higher appearance in malignant lymphoma than in lymph node metastasis (p=0,049). The results of the interobserver variance were different for each vascular pattern. They showed a high accordance between the investigators for longitudinal vessel and hypervascularity, a moderate accordance for hilar vessel, aberrant vessel und avascularity and a low or no accordance for the other vascular patterns respectively. CONCLUSION: There are three vascular patterns (avascular focus, aberrant vessel, subcapsular vessel) in power Doppler sonography, which are typical for malignant abdominal lymphadenopathy. The presence of one of these vascular patterns means with a high specifity (87-100%), that an abdominal lymph node is malignant. One vascular pattern (hiliar vessel) is typical for bengin lymphadenopathy.