Gray-scale contrast-enhanced ultrasonography in detecting sentinel lymph nodes: an animal study.
OBJECTIVE
To investigate the usefulness of gray-scale contrast-enhanced ultrasonography for detecting sentinel lymph nodes.


METHODS
Contrast-enhanced ultrasonography was performed in five normal dogs (four female and one male) after subcutaneous administration of a sonographic contrast agent (Sonovue, Bracco, Milan, Italy). Four distinct regions in each animal were examined. After contrast-enhanced ultrasonography, 0.8 ml of blue dye was injected into the same location as Sonovue and the sentinel lymph nodes were detected by surgical dissection. The findings of contrast-enhanced ultrasonography were compared with those of the blue dye.


RESULTS
Twenty-one sentinel lymph nodes were detected by contrast-enhanced ultrasonography while 23 were identified by blue dye with surgical dissection. Compared with the blue dye, the detection rate of enhanced ultrasonography for the sentinel lymph nodes is 91.3% (21/23). Two patterns of enhancement in the sentinel lymph nodes were observed: complete enhancement (5 sentinel lymph nodes) and partial enhancement (16 sentinel lymph nodes). The lymphatic channels were demonstrated as hyperechoic linear structures leading from the injection site and could be readily followed to their sentinel lymph nodes. Histopathologic examination showed proliferation of lymphatic follicles or lymphatic sinus in partial enhanced sentinel lymph nodes while normal lymphatic tissue was demonstrated in completely enhanced sentinel lymph nodes.


CONCLUSIONS
Sonovue combined with gray-scale contrast-enhanced ultrasonography may provide a feasible method for detecting sentinel lymph nodes.
Department of Ultrasound, Chinese People's Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China. wangyuexiang1999@sina.com
Yuexiang
Y
Wang
Zhigang
Z
Cheng
Junlai
J
Li
Jie
J
Tang
D000465:Algorithms; D000818:Animals; D003287:Contrast Media; D004285:Dogs; D005260:Female; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008297:Male; D010743:Phospholipids; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy; D013459:Sulfur Hexafluoride; D014463:Ultrasonography / Q000379:methods*
D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride