Ultrasonography.  2020 Jan;39(1):60-69. 10.14366/usg.19010.

Evaluation of lymph node metastasis in a rabbit tumor model: correlations between contrast-enhanced ultrasound and pathologic findings

• Ha SW
• Lee HJ
• Cho AS
• Hwang SI
• Lee HJ

• KMID: 2501431
• DOI: http://doi.org/10.14366/usg.19010

Abstract

Purpose
The purpose of this study was to evaluate the ability of contrast-enhanced ultrasonography (CEUS) with microbubbles to detect metastatic lymph nodes (LNs) for treatment planning and prognosis.
Methods
For the metastatic LN model, ground VX2 tumor tissues were injected subcutaneously in 12 rabbits, just below the right hind limb. The rabbits were classified into three groups based on the LN area: group A (n=4, >1.9 cm2 ), group B (n=4, 1-1.9 cm2 ), and group C (n=4, <1 cm2 ). The LNs were monitored on CEUS for 10 seconds after injecting 2.5 mL of microbubbles. The percent area of metastatic LNs was calculated on pathologic images and compared with CEUS images.
Results
In group A, the mean percent area of metastasis was 40.7%±19.4%. In all cases of metastasis, round-shaped perfusion defects were clearly observed in CEUS images. The metastatic areas were strongly correlated with pathologic findings. The mean percent area in group B was 21.5%±14.4%. The CEUS findings showed multiple nodular perfusion defects, clearly revealing the metastatic areas. In group B, the CEUS and pathologic findings were concordant for three of the four cases. The mean percent area in group C was 9.1%±6.4%. However, in this group, CEUS only detected a small perfusion defect in one case.
Conclusion
CEUS has the potential to depict characteristic imaging features of metastatic LNs but still has limitations in early detection.

Keyword

Lymph nodes; Lymphatic metastasis; Microbubbles; Ultrasonography; Diagnostic imaging