Post-Chemotherapy Canine Lymphomatous Lymph Node Observations on B-Mode and Strain Elastographic Ultrasound

Abstract

Simple Summary Canine multicentric lymphoma is a common hematopoietic neoplasm in dogs that initially responds well to treatment but often relapses due to chemotherapy resistance. Evaluating treatment response is crucial. Ultrasound can differentiate between benign and malignant lymph nodes, but its use post chemotherapy is limited. This study compared ultrasound parameters of lymphomatous lymph nodes during the first three weeks post treatment with normal lymph nodes from healthy dogs. Ultrasound, including B-mode and elastography, was performed pre-treatment and weekly for three weeks post treatment. Lymphomatous lymph nodes were categorized into partial response and stable disease groups. Ultrasound scores, combining B-mode and elastography parameters, were significantly higher in lymphomatous lymph nodes than normal lymph nodes. Lymphomatous lymph nodes at pre-treatment had higher values than post-treatment. Ultrasound scores significantly differed among healthy, partial response, and stable disease groups. Therefore, ultrasound can be effectively used in conjunction with the conventional method to evaluate treatment response. Abstract Canine multicentric lymphoma (CML) is a prevalent hematopoietic neoplasm that initially responds well to treatment but often relapses due to chemotherapy resistance. Evaluation of treatment response is essential for effective management. Ultrasound (US) can differentiate between benign and lymphomatous lymph nodes (LLNs). However, its utility in monitoring LLNs post chemotherapy is limited. This study aimed to compare US parameters of LLNs during the first 3 weeks post treatment and evaluate their diagnostic performance compared with the conventional method for assessing treatment response. This study included 95 LLNs from 15 dogs with CML and 60 normal lymph nodes (NLNs) from 15 healthy dogs. US, including B-mode and elastography, was performed pre-treatment and weekly for 3 weeks post treatment, and compared with the results of NLNs. LLNs were categorized into partial response and stable disease groups using the conventional method. US scores were established by combining B-mode and elastography parameters. The results showed significantly higher values of LLNs in the short-to-long axis ratio, elastographic scales, and blue-to-green color histogram compared with NLNs. Additionally, LLNs at pre-treatment had significantly higher values than LLNs post treatment. US scores significantly differed among the healthy, partial response, and stable disease groups. In conclusion, B-mode US, elastography, and US scores demonstrated changes during chemotherapy consistent with the conventional method and can be used in conjunction with the conventional method to evaluate the treatment response of CML.