Diagnostic Value of Diffusion Weighted Magnetic Resonance Imaging in Evaluation of Metastatic Neck Lymph Nodes in Head and Neck Cancer: A Sample of Iranian Patient

Abstract

Objective: To evaluate the diagnostic value of DWI in assessment of metastatic neck lymph node in a sample of<br />Iranian patients with Head and Neck cancer. Methods: 25 patients with 80 neck lymph nodes were analyzed using 1.5 T<br />MRI. DWI was performed with b values of 0 and 1,000 s/mm2. Short axis diameter and ADC values (min, max and mean)<br />were calculated for metastatic and non-metastatic neck LNs and results were compared with histopathological findings.<br />The optimal ADC thresholds were analyzed using receiver coefficient characteristic (ROC) curves for discriminating<br />between metastatic and benign neck lymph nodes. Result: Histopathological findings revealed that there are 45% (n=36)<br />metastatic and 55% (n=44) non-metastatic neck LNs respectively. There was no statistically significant difference in<br />short axis diameter between the two groups (p = 0.346). However, The ADC values of metastatic neck LNs were<br />significantly lower than those of non-metastatic neck LNs (p < 0.001); 0.90 ± 0.10 × 10-3 mm2/s vs 1.06 ± 0.12 × 10-3<br />mm2/s ( ADC mean ), 0.78 ± 0.08 × 10-3 mm2/s vs 0.92 ± 0.20× 10-3 mm2/s ( ADC min ) and 1.02 ± 0.12 × 10-3 mm2/s<br />vs 1.24 ± 0.15 × 10-3 mm2/s (ADC max ). The optimal mean ADC threshold value was equal to 0.996 × 10-3 mm2/s<br />for differentiating malignant from benign lymph nodes with sensitivity, specificity and accuracy of 80.56 %, 77.27 %<br />and 71.59 % respectively. Conclusion: MR diffusion imaging and ADC values as a non-invasive technique can assess<br />metastatic neck LNs in head and neck cancer with higher sensitivity, specificity and accuracy.