Evaluating Different Quantitative Shear Wave Parameters of Ultrasound Elastography in the Diagnosis of Lymph Node Malignancies: A Systematic Review and Meta-Analysis

SIMPLE SUMMARY: Ultrasound (US) imaging is a safe, convenient imaging method for identifying malignant lymph nodes. Shear wave elastography (SWE), as a type of US elastography offers the mechanical information of tissue by sensing shear wave propagation in lymph nodes. Malignant lymph nodes can show increased stiffness at the lesion margin and adjacent tissue on the SWE image. However, the diagnostic accuracies of various SWE parameters that quantify tissue stiffness, such as maximum stiffness, mean stiffness, minimum stiffness, and standard deviation, are yet to be demonstrated. We included sixteen eligible studies to evaluate the pooled diagnostic accuracy of different SWE parameters. SWE has demonstrated promise as an imaging modality in diagnosing and differentiating malignancy from benign lymph nodes. Its incorporation into standard US allows for a better evaluation of the target region or lymph node and might reduce the need for invasive procedures or exposure to ionising radiation without compromising on diagnostic accuracy. ABSTRACT: Shear wave elastography (SWE) has shown promise in distinguishing lymph node malignancies. However, the diagnostic accuracies of various SWE parameters that quantify tissue stiffness are yet to be demonstrated. To evaluate the pooled diagnostic accuracy of different SWE parameters for differentiating lymph node malignancies, we conducted a systematic screening of four databases using the PRISMA guidelines. Lymph node biopsy was adopted as the reference standard. E(max) (maximum stiffness), E(mean) (mean stiffness), E(min) (minimum stiffness), and E(sd) (standard deviation) SWE parameters were subjected to separate meta-analyses. A sub-group analysis comparing the use of E(max) in cervical (including thyroid) and axillary lymph node malignancies was also conducted. Sixteen studies were included in this meta-analysis. E(max) and E(sd) demonstrated the highest pooled sensitivity (0.78 (95% CI: 0.69–0.87); 0.78 (95% CI: 0.68–0.87)), while E(mean) demonstrated the highest pooled specificity (0.93 (95% CI: 0.88–0.98)). From the sub-group analysis, the diagnostic performance did not differ significantly in cervical and axillary LN malignancies. In conclusion, SWE is a promising adjunct imaging technique to conventional ultrasonography in the diagnosis of lymph node malignancy. SWE parameters of E(max) and E(sd) have been identified as better choices of parameters for screening clinical purposes.