Barry B. Goldberg MD, Abstract Co-Author: Nothing to Disclose

Daniel Arthur Merton, Abstract Co-Author: Nothing to Disclose

Ji-Bin Liu MD, Presenter: Research Grant, General Electric Company Research Grant, GluMetrics, Inc

Adam Berger MD, Abstract Co-Author: Nothing to Disclose

Agnieszka Witkiewicz MD, Abstract Co-Author: Nothing to Disclose

John Robery Eisenbrey PhD, Abstract Co-Author: Nothing to Disclose

Flemming Forsberg PhD, Abstract Co-Author: Equipment support, Toshiba Corporation Equipment support, Siemens AG Research collaboration, General Electric Company Research collaboration, Ultrasonix Medical Corporation Research collaboration, Toshiba Corporation Advisory Board, Siemens AG Advisory Board, Toshiba Corporation

To investigate the use of CEUS for detection of secondary lymph nodes (2LNs) in a melanoma swine model compared to surgery and pathology.

Twenty-seven swine were studied. 1 mL of Sonazoid (GE Healthcare, Oslo, Norway) was administered around the melanoma and CEUS was used to localize CE sentinel lymph nodes (SLNs). Sonazoid (dose 0.2-0.5 ml) was then injected under US-guidence into the SLNs to detect CE efferent lymphatic channels and 2LNs. After peritumoral injection of blue dye a surgeon who was blinded to the CEUS results performed a radical LN resection (RLNR). Pathology was used to identify metastases within resected LNs. Clustered conditional logistic regression analysis tested the benefit of CEUS directed 2LN resection over RLNR calculated as an odds ratio (OR) using pathology as the gold standard. The detection of metastases in the 2LNs identified with CEUS or RLNR was compared using McNemar’s test.

268 2LNs were resected; 59 contained metastases. CEUS detected 92 2LNs, 248 were identified by RLNR and 68 were identified by both methods. Metastases were detected in 21% (51/248) and 40% (37/92) of the 2LNs identified by RLNR and CEUS respectively. Thus, 2LNs detected by CEUS were nearly 5X more likely to contain metastases than 2LNs removed by RLNR (OR=4.8, p<0.0001). Metastases in 2LNs were detected in 78% (21/27) of the swine. RLNR correctly determined that 21 swine had 2LN metastases but 6 swine were incorrectly assumed to have 2LN metastases. CEUS correctly predicted 20 swine had 2LN metastases and 2 swine as not having metastases (accuracy: 82%; 22/27). No statistically significant difference was found in the number of swine diagnosed correctly based on CEUS compared to RLNR (p= 0.56). When the decision to remove a 2LN or not was assessed on a per 2LN basis there was a statistically significant difference between decisions based on CEUS relative to RLNR (p < 0.0001). Twenty-two metastatic 2LNs were not detected with CEUS. CEUS identified 19 2LNs after the surgeon completed RLNR of which 42% (8/19) contained metastases.

2LNs can be detected using CEUS after injection of Sonazoid into SLNs. 2LNs detected with CEUS are significantly more likely to contain metastases than those removed by RLNR.

This study using a swine with naturally-occuring melanoma tumors suggests that contrast-enhanced ultrasound imaging has the potential to improve lymph node surgery.

Goldberg, B, Merton, D, Liu, J, Berger, A, Witkiewicz, A, Eisenbrey, J, Forsberg, F, Detection of Secondary Lymph Nodes with Contrast-Enhanced Ultrasound Imaging (CEUS).  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12027573.html