Value of acoustic radiation force impulse imaging in the differential diagnosis of the superficial lymphadenopathy

Abstract

Objective To investigate the application value of virtual touch tissue image technology (VTI) and virtual touch tissue quantification technique (VTQ) in the differential diagnosis of benign and malignant superficial lymph nodes. Methods Fifty superficial lymph nodes were obtained, including 23 for nonspecific inflammatory, 2 for tuberculosis, 5 for lymphoma and 20 for metastasis. All lymph nodes were confirmed by biopsy pathology or follow-up after anti-inflammatory treatments and scanned by ultrasound, VTI and VTQ before resections or treatments. Receiver operating characteristic curve of ultrasound, VTI and VTQ was made to determine the optional cut-off point in the differential diagnosis of benign and malignant superficial lymph nodes and calculate the sensitivity, specificity, accuracy, positive predictive value and negative predictive value. Final diagnosis was defined as the golden standard. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value were calculated by the combined application of ultrasound with VTI and VTQ technology. Results Nine (evaluation value) was taken as the critical value which was scanned by both two-dimensional ultrasound and color Doppler. The ROC curve indicated that the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of conventional two-dimensional ultrasound of benign and malignant lymph nodes were 76.0%, 84.0%, 80.0%, 82.6%, and 77.8%. Taking three (critical value) as the cut-off point, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of VTI in the diagnosis of benign and malignant lymph nodes were 88.0%, 64.0%, 76.0%, 71.0% and 84.2%. Taking 2.755 m/s (shear wave velocity) as the cut-off value, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of VTQ in the differentiation of benign and malignant superficial lymph nodes were 80%, 92.0%, 86.0%, 90.9% and 82.1%. Defined traditional ultrasound +VTI+VTQ series as using conventional ultrasound, VTI, VTQ simultaneously, superficial lymph nodes could be diagnosed with malignant or benign if each method confirmed the same diagnosis. Defined traditional ultrasound +VTI+VTQ parallel as using conventional ultrasound, VTI, VTQ simultaneously, superficial lymph nodes could be diagnosed with malignant if any one method indicated malignancy, otherwise benign. Specificity of 'traditional ultrasound +VTI+VTQ series method’ was consistent with VTQ, which was 92.0%, while the sensitivity and accuracy decreased significantly, which was 64.0% and 78.0%, respectively; the sensitivity and negative predictive value increased significantly by using traditional ultrasound +VTI+VTQ parallel when compared with ultrasound, VTI or VTQ, almost near 100%, but declined significantly in specificity and accuracy, which was 64.0% and 82.0%, respectively. Conclusions Traditional ultrasound, VTI and VTQ have certain clinical value for differential diagnosis of benign and malignant superficial lymph nodes. Combined application of ultrasound, VTI and VTQ can improve the accuracy in the diagnosis of benign and malignant lymph nodes effectively. Key words: Elasticity imaging techniques; Lymph nodes; Diagnosis, differential