The application of grayscale quantitative analysis in the differential diagnosis of necrosis between cervical lymph node metastases in nasopharyngeal carcinoma and tuberculous lymphadenitis.

OBJECTIVE: To investigate the diagnostic value of ultrasound grayscale difference in differentiating necrotic cervical lymph node metastases from nasopharyngeal carcinoma (NPC) and cervical tuberculous lymphadenitis (CTL), and to provide an objective imaging index for clinical differential diagnosis. MATERIALS AND METHODS: A retrospective study in 2023 enrolled 115 patients with necrotic cervical lymphadenopathy, including 27 with NPC and 88 with CTL. All patients underwent conventional ultrasound, contrast-enhanced ultrasound (CEUS), and ultrasound-guided biopsy. The grayscale difference of necrotic areas was measured by RadiAnt DICOM Viewer. SPSS 25.0 was used for statistical analysis, including univariate and multivariate regression for indicator screening, and receiver operating characteristic (ROC) curves for evaluating diagnostic efficacy. RESULTS: The ultrasound grayscale difference was 48.07 ± 11.73 in the NPC group, significantly higher than 20.33 ± 9.31 in the CTL group (p<0.001). The area under the ROC curve (AUC) of grayscale difference was 0.97, with a cutoff value of 31.5, yielding a sensitivity of 96.3% and specificity of 90.9%. The multivariate regression model achieved an AUC of 0.97, with sensitivity of 95.5% and specificity of 92.6%. Age and gender differed significantly between groups (p<0.05), while lymph node diameters showed no significant difference (p>0.05). CONCLUSION: Ultrasound grayscale difference has high diagnostic value in distinguishing necrotic cervical lymph node metastases of NPC from CTL, and can serve as a reliable quantitative imaging indicator. The multivariate regression model further improves diagnostic accuracy and supports clinical decision-making.