The Diagnostic Value of Diffusion-Weighted Imaging in Differentiating Metastatic Lymph Nodes of Head and Neck Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

Abstract

Background: Accurate lymph node staging is crucial for proper treatment planning for metastasis in patients with head and neck squamous cell carcinoma.

Purpose: Our aim was to evaluate the diagnostic performance of DWI for differentiating metastatic cervical lymph nodes from benign cervical lymph nodes in patients with head and neck squamous cell carcinoma and to identify optimal cutoff values for ADC.

Data sources: A computerized literature search was performed to identify relevant original articles in Ovid MEDLINE and EMBASE.

Study selection: Studies evaluating the diagnostic performance of DWI for differentiating metastatic cervical lymph nodes from benign cervical lymph nodes were selected.

Data analysis: Diagnostic meta-analysis was conducted with a bivariate random-effects model, and a hierarchical summary receiver operating characteristic curve was obtained. Meta-regression was also performed.

Data synthesis: Nine studies with 337 patients were included. In all studies, ADC values derived from metastatic lymph nodes were significantly lower than ADC values derived from benign lymph nodes. The median ADC cutoff value was 0.965 × 10^-3 mm²/s. The pooled sensitivity and specificity for the diagnostic performance of DWI in differentiating metastatic lymph nodes from benign lymph nodes were 90% (95% CI, 84%-94%) and 88% (95% CI, 80%-93%), respectively. In the meta-regression, sensitivity was significantly higher in the studies using a 3-mm slice thickness (93% [95% CI, 88%-98%]) than in studies using a slice thickness of >3 mm (86% [95% CI, 77%-95%], P < .01).

Limitations: A small number of studies were included in our meta-analysis.

Conclusions: DWI demonstrated high diagnostic performance for differentiating metastatic lymph nodes from benign lymph nodes in patients with head and neck squamous cell carcinoma, and the median ADC cutoff value was 0.965 × 10^-3 mm²/s. A 3-mm DWI slice thickness can provide a slight improvement in sensitivity.

Fig 1.

Flowchart depicting the literature search and study selection.

Fig 2.

Grouped bar charts indicating methodologic quality according to the QUADAS-2 criteria and expressed as the percentage of studies meeting each criterion. For each quality domain, the proportions of studies suggesting a low, high, or unclear risk of bias and/or concerns regarding applicability are illustrated in green, red, and blue, respectively.

Fig 3.

Coupled forest plots showing the diagnostic performance of each study. Vertical lines in the coupled forest plots show the pooled sensitivity and specificity.

Fig 4.

Hierarchical summary receiver operating characteristic curve with 95% confidence and prediction regions of DWI for differentiating metastatic LNs from benign LNs in patients with HNSCC. Each circle indicates 1 included study.

Fig 5.

The Deeks funnel plot showing the presence of publication bias. Numbers in circles refer to study number. ESS indicates effective sample size.