Change of sonographic findings on cervical lymph nodes before and after preoperative radiotherapy

The aim of this study was to assess the changes in the power Doppler sonographic findings in patients with oral cancer undergoing chemotherapy and radiotherapy. We performed US examinations on 187 cervical lymph nodes (71 metastatic and 116 reactive nodes) excised from 52 patients before and after preoperative therapy. On Power Doppler images, we calculated the vascular index (VI) and evaluated the vascular pattern. We also assessed the diagnostic power using receiver operating characteristic (ROC) curve analysis. Irradiation caused an increase of the VI and better visualization of the vessels within the lymph node in the reactive nodes; however, in the metastatic nodes, the VI was not significantly different between that before and after irradiation. When the reader observed the images before irradiation, the area under an ROC curve (Az values) observed by B-mode sonography were closely similar to those obtained by B-mode plus power Doppler sonography. With both images before and after irradiation, the Az value obtained by B-mode plus power Doppler sonography was higher than that by B-mode sonography alone. After irradiation, the enhanced Doppler signals contributed to a better visualization of the vessels and a better detection of any vascular abnormalities.