UPmémoires

English

Introduction:

Lymph node (LN) metastases is an important prognostic factor in Head and Neck cancer especially squamous cell carcinoma (HNSCC) as this significantly worsens the treatment outcome. Several studies have highlighted the value of diffusion-weighted imaging (DWI) by MRI as a non-invasive technique for differentiating between benign and malignant LNs. We aimed to evaluate the performance of ADC values as a basis for diagnosis of LN metastasis in head and neck carcinoma patients.

Materials and methods:

This was a retrospective study of histological results from neck dissection in 38 patients with head and neck neoplasia who previously received MRI with DWI between July 2016 and August 2021. The mean ADC values were measured and compared with histological proven LNs using standardized coefficient. The same comparison was performed, at 3T, with the Wilcoxon test. Receiver operating characteristic (ROC) curves analysis were performed to determine the ADC cutoff value.

Results:

A total of 53 lymph nodes—32 benign and 21 metastatic—were included. The mean ADC values of metastatic (0,98.10-3mm2/s) LNs were significantly different from those of non-metastatic LNs (1,23.10-3mm2/s) (p=0,019). This difference was mostly found at 3T (p=0,038), but not at 1,5T (p=0,6). An ADC cutoff value was 1,025.10-3mm2/s with 83,3% sensitivity, 64,3% specificity, 66,7% positive predictive value, and 81,8% negative predictive value.

Conclusion:

ADC measurement is useful in differentiating reactive and metastatic cervical LNs in Head and Neck Cancer patients, especially at 3T. However, ADC threshold value should be use with caution because of the poor statistic parameters.

Keywords : Head and neck cancer, lymph node, diffusion-weighted imaging, apparent diffusion coefficient.