Evaluation of supplementary diagnostic value of contrast-enhanced ultrasound for lymph node puncture biopsy

Contrast enhanced ultrasound (CEUS) is an effective way to evaluate the distribution of micro vessels in organs with little invasiveness. The qualitative evaluation and differential diagnosis of lymph node is essential for a number of clinical situations, including appropriate examination selection, oncologic staging, therapy and prognosis beyond diagnosis itself. The purpose of this study is to investigate the contribution of characterization of cervical lymphadenopathies on CEUS as an indication for lymph node puncture biopsy.

Records of 157 lymph nodes from 103 patients who had undergone CEUS examination were studied retrospectively, and enhancement patterns and characteristics were evaluated. The diagnoses obtained by means of core-needle biopsy examination or surgical removal, or patients were closely followed-up for at least 6 months. Of the lymph nodes examined, 94 were benign (48 lymphadenitis and 46 tuberculosis) and 63 were malignant (55 metastases and 8 lymphomas). The vascular characterization of lymph nodes was compared with results obtained by pathologic examination.

The study using CEUS showed 55 (54.5%) cases of "peripheral" enhancement in group A and 47 (83.9%) cases of "hilar normal or activated" in group B. Inhomogeneous "spotted or cycle-like" enhancement in the equilibrium phase was seen in 80 (79.2%) cases of group A and only 11 (19.6%) cases of group B. The specificity, sensitivity and accuracy of CEUS examination result as an indication for puncture biopsy were 80.4%, 81.2% and 80.9%, respectively.

Centripetal perfusion in the early arterial phase or inhomogeneous spotted or cycle-like enhancement in the equilibrium phase of the cervical lymph nodes during CEUS can be used as an indication for core-needle biopsy with a high degree of accuracy. Conversely, for lymph nodes with more variable appearances, surgical removal or closely followed-up of nodes may be more appropriate.