Clin Exp Otorhinolaryngol.  2017 Mar;10(1):109-114. 10.21053/ceo.2015.01284.

Evaluation of Neck Lymph Node Metastasis on Contrast-Enhanced Ultrasound: An Animal Study

• Cui Z
• Gao Y
• Wang W
• Zhu Z
• Zhang Y
• Ma Z

• KMID: 2376417
• DOI: http://doi.org/10.21053/ceo.2015.01284

Abstract

OBJECTIVES
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.
CONCLUSION
CEUS can play a role in discriminating metastatic from hyperplastic lymph nodes in head and neck carcinoma.

Keyword

Ultrasonography; Head and Neck Neoplasms; Lymph Node Metastasis

MeSH Terms

Administration, Intravenous
Animals*
Egg Yolk
Head
Head and Neck Neoplasms
Inflammation
Lymph Nodes*
Models, Animal
Neck*
Neoplasm Metastasis*
Rabbits
Tongue
Ultrasonography*

Figure

• 

  Fig. 1. Conventional ultrasonography before injection of Sonovue (Bracco, Milan, Italy). (A) Hyperplastic group and (B) metastasis group. Both group showed an oval shaped smooth bordered low echogenicity, but whether the lymph nodes were hyperplastic or malignant cannot be evaluated.

• 

  Fig. 2. The ultrasonic appearance of a lymph node in the hyperplastic group after the injection of Sonovue (Bracco, Milan, Italy). Contrast enhanced sonogram showed intense and homogenous enhancement of lymph node echogenicity, and the enhancement starts from the central area of the lymph node (centrifugal enhancement). (A) Five seconds after the injection and (B) 10 seconds after the injection.

• 

  Fig. 3. The ultrasonic appearance of a lymph node in the metastasis group after the injection of Sonovue (Bracco, Milan, Italy). Contrast enhanced sonogram showed heterogeneous enhancement of lymph node echogenicity, and the enhancement started from both the central and peripheral area of the lymph node (diffuse enhancement). (A) Three seconds after the injection and (B) 10 seconds after the injection.

• 

  Fig. 4. The ultrasonic appearance of another lymph node in the metastasis group after the injection of Sonovue (Bracco, Milan, Italy). Contrast enhanced sonogram showed heterogeneous enhancement of lymph node echogenicity, and the enhancement started from the peripheral area of the lymph node (centripetal enhancement). (A) Three seconds after the injection and (B) 10 seconds after the injection.

• 

  Fig. 5. Lymph node metastasis of poorly differentiated squamous cell carcinoma with partial necrosis (H&E, ×200).

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