New method of sentinel node detection using a combination of contrast-enhanced ultrasound and dye guidance: an animal study.
OBJECTIVE
To determine whether a combination of contrast-enhanced ultrasound-guided methods and dye-guided methods can identify sentinel lymph nodes in animals.


METHODS
Seven pigs were put under general anesthesia and injected subcutaneously in the neck: three with 2 ml saline and four with 2 ml fluid comprising 0.4 ml 5% patent blue violet solution and 1.6 ml of hydroxyethylated starch (Salinhes) solution (PB + HS). The regional lymph nodes were observed by ultrasound; blue-stained regional lymph nodes found after the skin was cut were situated as ultrasound had shown they would be.


RESULTS
The regional lymph nodes of the pigs given saline were unchanged, but in the pigs receiving PB + HS, the echo level in the lymph nodes nearest the injection site was altered, producing a clear contrast with the surrounding tissues. The area of the relevant regional lymph node in each PB + HS-injected pig increased significantly (t-test, P < 0.01; from 25.7, 39.6, 9.36, 70.2 mm(2), and mean, 36.2 mm(2); to 50.7, 65.5, 21.1, 98.3 mm(2), and mean, 58.9 mm(2), respectively). These enlarged regional lymph nodes were easily found by contrast-enhanced ultrasonography. When excised under ultrasound guidance, all were stained blue, indicating that they were sentinel lymph nodes.


CONCLUSIONS
These results suggest that this combination of contrast-enhanced ultrasound-guided and dye-guided methods warrants use as a quick, simple procedure for detecting sentinel lymph nodes.
Department of Clinical Laboratory Medicine, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. kiyoka@jichi.ac.jp.
Kiyoka
K
Omoto
Department of Surgery, Jichi Medical University, Tochigi, Japan.
Yasuo
Y
Hozumi
Department of Surgery, Jichi Medical University, Tochigi, Japan.
Yoshito
Y
Nihei
Department of Surgery, Jichi Medical University, Tochigi, Japan.
Yawara
Y
Omoto
Department of Surgery, Jichi Medical University, Tochigi, Japan.
Hirobumi
H
Mizunuma
Department of Surgery, Jichi Medical University, Tochigi, Japan.
Hideo
H
Nagai
Department of Clinical Laboratory Medicine, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan.
Harumi
H
Koibuchi
Department of Clinical Laboratory Medicine, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan.
Yasutomo
Y
Fujii
Department of Clinical Laboratory Medicine, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan.
Nobuyuki
N
Taniguchi
Department of Clinical Laboratory Medicine, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan.
Kouichi
K
Itoh
animal model; contrast-enhanced ultrasound-guided method; dye-guided method; hydroxyethylated starch (Salinhes); sentinel lymph node; ultrasonography