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

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 VX 2 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 cm 2 ), group B (n=4, 1-1.9 cm 2 ), and group C (n=4, <1 cm 2 ). 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.

Diagnosing sentinel lymph node metastasis of T1/T2 breast cancer with conventional ultrasound combined with double contrast-enhanced ultrasound: a preliminary study

“…The results indicated that the enhancement of nonmetastatic SLNs tended to be type I with homogeneous enhancement, while that of metastatic SLNs tended to be type II or III with heterogeneous enhancement. The reason for this finding may be that lymph node metastasis is mainly caused by tumor cells entering lymph nodes through LCs, which leads to the destruction of the normal structure of lymph nodes ( 23 ). In this case, the contrast agent cannot flow into the tissue after entering LCs, thus forming filling defects.…”

Lymph node metastasis in oral squamous cell carcinoma: Where we are and where we are going

“…77 Consequently, in the burgeoning era of tumour immunotherapy, it is crucial to establish effective in vivo models such as mice, 97 zebrafish, 98 or rabbits. 99 Regarding in vitro research, the limitations of 2D cell culture models have driven the development of 3D models, which better mimic the natural tissue's cellular microenvironment. Spheroids, organoids, and 3D bioprinting are commonly used methods for creating 3D models, with substantial potential for studying LNM.…”

“…Recent research posits that the lymph node is more than a passive staging area during metastasis; it is a crucial site for initiating systemic immunosuppression 77 . Consequently, in the burgeoning era of tumour immunotherapy, it is crucial to establish effective in vivo models such as mice, 97 zebrafish, 98 or rabbits 99 . Regarding in vitro research, the limitations of 2D cell culture models have driven the development of 3D models, which better mimic the natural tissue's cellular microenvironment.…”

Clinical applications of Doppler ultrasonography for thyroid disease: consensus statement by the Korean Society of Thyroid Radiology

“…Additionally, contrast-enhanced US (CEUS) refers to the application of US contrast agents in medical US. CEUS can provide anatomic information with gray-scale US and physiologic information through the SDUS, CDUS, and PDUS techniques, making it indispensable in the assessment of vascular pathology [15][16][17][18][19][20][21]. The presence of a microbubble US contrast agent in the vasculature enhances the backscattering of US waves, resulting in a marked amplification of flow signals and providing information on the microvasculature [12,21,22].…”

“…The emerging modality of SMI can reveal more vascular details than CDUS or PDUS [ 33 - 35 ]. However, the populations in previous studies had a wide range of prevalence of papillary thyroid carcinomas (63.3%-90.6%) [ 16 , 44 - 46 ]. The parameters of SDUS, including PI and RI, may be important in differentiating benign from malignant thyroid nodules [ 28 , 29 , 31 , 38 , 39 ].…”