Lymph node metastases of cutaneous melanoma: Diagnosis by B-scan and colorDoppler sonography

Background: Sonography is a sensitive, noninvasive method that can be used to detect regional lymph node metastases. Color Doppler sonography (CDS) ca n supply further information on lymph node perfusion. Objective: We evaluated the usefulness of CDS for differentiating between b enign lymphadenopathies and lymph node metastases of cutaneous melanoma. Methods: In a prospective study, reactive inflammatory lymph nodes (rLN) an d lymph node metastases of cutaneous melanoma (mLN) were examined by sonogr aphy and CDS. Lymph node echogenicity and shape (length/depth ratio) were d etermined by sonography. The vascularization pattern of the lymph nodes was established with CDS. We recorded the Doppler frequency spectra at the hil l of the lymph nodes and then calculated the resistance and pulsatility ind ices (RI, PT). Results: The echogenicity of the lymph node centers had a sensitivity of 96 % and a specificity of 100%. The shape differed highly significantly betwee n the two groups (P < .001). The criterion length/depth ratio < 2 had a sen sitivity of 85% and specificity of 86%. Hilus vessels could be detected in 14 of 22 rLN (64%). These vessels, however, were not present in any of the metastases. The RI and the PI in detectable lymph node vessels differed bet ween the two groups (RI: P < .05; PI: not significant), but because of the overlap between the two groups, these indices were of no diagnostic value. In the presence of 2 or more of the following 3 criteria: length/depth rati o < 2, hypoechoic center, and the absence of hilus vessels, diagnosis of me tastasis of malignant melanoma had a sensitivity of 100% and a specificity of 96%. Conclusion: CDS improves the diagnostic accuracy of conventional sonography . The measurement of Doppler curves in lymph node vessels and the calculati on of pulsatility and resistance indices, on the other hand, is time-consum ing and seems to be of no diagnostic value.