Purpose: To perform a systematic review and meta-analysis of literature comparing average apparent diffusion coefficient (ADC) for differentiating lymphomatous, metastatic, and non-malignant cervical lymphadenopathy.
Methods: We performed a comprehensive literature search of Ovid MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science Core Collection. Studies comparing average ADC of lymphomatous, metastatic, and non-malignant neck lymph nodes were included. The standardized mean difference and 95% confidence interval (CI) was calculated using random-effects models. In subgroup analysis of those studies applying ADC threshold for differentiation of cervical lymphadenopathy, pooled diagnostic odds ratio (DOR) and summary receiver operating characteristics (sROC) area under the curve (AUC) were determined.
Results: A total of 27 studies with 1165 patients were included, pooling data from 225 lymphomatous, 1162 metastatic, and 1333 non-malignant cervical lymph nodes. The average ADC values were lower in lymphomatous compared to metastatic nodes, and in metastatic compared to non-malignant nodes with a standardized mean difference of - 1.36 (95% CI: - 1.71 to - 1.01, p < 0.0001) and - 1.61 (95% CI: - 2.19 to - 1.04, p < 0.0001), respectively. In subgroup analysis, applying ADC threshold could differentiate lymphomatous from metastatic lymphadenopathy with DOR of 52.07 (95% CI 25.45-106.54) and sROC AUC of 0.936 (95% CI 0.896-0.979) and differentiate metastatic from non-malignant nodes with DOR of 39.45 (95% CI 16.92-92.18) and sROC AUC of 0.929 (95% CI 0.873-0.966).
Conclusions: Quantitative assessment of ADC can help with differentiation of suspicious cervical lymph nodes, particularly in those patients without prior history of malignancy or unknown primary cancer site.
Keywords: Apparent diffusion coefficient; Cervical lymphadenopathy; Lymphoma; Metastasis.