Quantitative and qualitative analysis of contrast-enhanced ultrasound for differentiating benign and malignant superficial enlarged lymph nodes.

Background: In many clinical situations, it is critical to exclude or identify abnormally lymph nodes (LNs). The nature of superficial abnormally LNs is closely related to the stage, treatment, and prognosis of the disease. Ultrasound (US) is an important method for examining superficial LNs due to its cheap and safe characteristics. However, it is still difficult to determine the nature of some LNs with overlapping benign and malignant features in images. Contrast-enhanced ultrasound (CEUS) can be used to evaluate the microperfusion status of tissues in real time, and it can improve diagnostic accuracy to a certain extent. Therefore, in this study, we will analyze the correlation between CEUS quantitative parameters and benign and malignant superficial abnormally LNs, to evaluate the efficacy and value of CEUS in distinguishing benign and malignant superficial LNs.

Methods: This study retrospectively analyzed 120 patients of abnormal LNs who underwent US and CEUS at the China-Japan Union Hospital of Jilin University from December 2020 to August 2023. All 120 cases of abnormal LNs underwent US-guided coarse needle biopsy, and accurate pathological results were obtained, along with complete US and CEUS images. According to the pathological results, LNs were divided into benign and malignant groups, and the qualitative and quantitative parameters of US and CEUS between the two groups were analyzed. The cutoff value is determined by the receiver operating characteristic (ROC) curve of the subjects, and sensitivity, specificity, and accuracy are applied to evaluate the ability of the cutoff value to distinguish between the two groups.

Results: There were a total of 120 LNs, including 36 in the benign group and 84 in the malignant group. The results showed that malignant LNs were usually characterized by the disappearance of lymphatic hilum, round ness index (L/T) <2, irregular morphology, and the manifestation of uneven perfusion (P<0.05). The differences in the quantitative parameters peak enhancement (PE), rise time (RT), time to peak (TTP), wash-in rate (WIR), and wash-out rate (WOR) were statistically significant (P<0.05). The result showed that RT and TTP in the malignant LNs were higher than those in the benign LNs, while the PE, WIR, and WOR were lower. A comparison of the ∆ values showed that the differences in ∆PE, ∆WIR, and ∆fall time (FT) were statistically significant (P<0.05), Among them, the ∆PE and ∆WIR of malignant LNs were higher than those of benign LNs, while the ∆FT was lower than that of benign LNs.

Conclusions: Quantitative analysis of CEUS features is valuable in the diagnosis of benign and malignant LNs, and US combined with CEUS helps to improve the accuracy of identifying the nature of LNs.