Barry Benson Goldberg MD, Presenter: Nothing to Disclose

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

Ji-Bin Liu MD, Abstract Co-Author: Nothing to Disclose

Mohan Aruva PhD, Abstract Co-Author: Nothing to Disclose

Kaijun Zhang MD, PhD, Abstract Co-Author: Nothing to Disclose

Traci B. Fox BS, Abstract Co-Author: Nothing to Disclose

Flemming Forsberg PhD, Abstract Co-Author: Support, Regeneron Pharmaceuticals, Inc

Mathew L. Thakur PhD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To compare lymphosonography {i.e., ultrasound imaging (US) after peritumoral injection of a reticuloendothelial system-specific US contrast agent} for the detection of sentinel lymph nodes (SLNs) in swine with naturally occurring melanoma tumors to lymphoscintigraphy using blue dye-guided surgical dissection as the gold standard. Also to correlate melanoma size with the number of draining SLNs.

Twenty-eight swine with 51 melanomas were evaluated. Sonazoid (GE Healthcare, Oslo, Norway), which is taken-up by the lymphatic system and retained in SLNs, was administered around each tumor (1 ml dose). Grayscale phase-inversion harmonic US was performed with an Elegra system (Siemens Medical, Issaquah, WA). Lymphoscintigraphy was performed with a Starcam 300 (GE Healthcare, Milwaukee, WI) after peritumoral injections of Tc99m. Peritumoral injections of blue dye were performed around each melanoma and the dye-filled lymphatic channels were used to locate SLNs surgically. The accuracy of SLN detection with the 2 imaging modes was compared using the sign rank test. Tumor size was correlated to the number of SLNs identified per tumor using linear regression analysis.

Blue dye-guided surgery identified 177 SLNs, lymphosonography identified 156 SLNs {including 4 false positives; (FPs)} and lymphoscintigraphy identified 112 "hot spots" suspected of representing SLNs (including 13 FPs). Lymphosonography failed to detect 21 SLNs while lymphoscintigraphy missed 65 SLNs. The accuracy of SLN detection was 87% for lymphosonography, which was significantly higher than the 60% achieved with lymphoscintigraphy (p<0.0001). The number of SLNs per tumor ranged from 1 to 9 (avg. 3.6). Melanoma size correlated with the number of SLNs (r=0.38; p<0.01).

Lymphosonography was statistically better than lymphoscintigraphy for the detection of SLNs in this animal model. The size of the melanoma correlated with the number of its SLNs. This research was funded by a grant from the NIH (CA100370). Sonazoid was provided by GE Healthcare, Oslo, Norway.

Lymphosonograhy has the potential to improve the detection of SLNs.

Goldberg, B, Merton, D, Liu, J, Aruva, M, Zhang, K, Fox, T, Forsberg, F, Thakur, M, et al, , et al, , Contrast-enhanced Sonographic Detection of Sentinel Lymph Nodes in Swine with Melanomas: Comparison to Nuclear Medicine with Blue Dye-guided Surgery as the Gold Standard.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5011063.html