title: Evaluation of Neck Lymph Node Metastasis on Contrast-Enhanced Ultrasound: An Animal Study.
abstract: OBJECTIVE
  To assess the performance of contrast-enhanced ultrasound (CEUS) intended to differentiate hyperplastic from malignant neck lymph nodes in an animal model.
  
  
  METHODS
  Twenty-four New Zealand rabbits were randomly divided into two groups: neck lymph node metastasis group (12 rabbits) and reactive hyperplastic lymph node group (12 rabbits). Tongue VX2 carcinoma with cervical lymph node metastasis was induced in 12 rabbits by injecting VX2 carcinoma suspension into the left tongue submucosa. Hyperplastic neck lymph nodes were induced by injecting egg yolk in the submandibular region of the rabbits in hyperplastic group. CEUS were performed in both groups before and after intravenous administration of SonoVue. The site, number, echogenicity, longitudinal and transverse nodal dimensions, patterns of enhancement of the neck lymph nodes were observed and recorded.
  
  
  RESULTS
  In both groups only one lymph node was found in the left (tumor) side of the neck. CEUS found 12 of 12 metastatic lymph nodes in metastasis group, and diagnosed 11 of 12 lymph nodes as metastatic. Histopathologic analysis revealed metastatic lesions in all 12 rabbits, each with one lymph node, and all 12 lymph nodes in hyperplastic group is inflammation lymph nodes. All 12 cases in the hyperplastic group showed centripetal homogeneous enhancement while in the metastasis group one case showed centripetal homogeneous enhancement, three cases showed centrifugal heterogeneous enhancement, and eight cases showed diffused heterogeneous enhancement. Only one lymph node was dissected on the left side of the neck in each rabbit in both groups.
  
  
  CONCLUSIONS
  CEUS can play a role in discriminating metastatic from hyperplastic lymph nodes in head and neck carcinoma.
authors.affiliation: Department of Ultrasound Diagnosis, East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Cui
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Zhenghua
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Zhaoxin
authors.initials: Z
authors.lastname: Ma
keywords: Head and Neck Neoplasms; Lymph Node Metastasis; Ultrasonography