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

Document Type: Research Articles

Authors

1 Department of Radiology Technology, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

2 Ear Nose Throat (ENT) and Head and Neck Surgery Research Center, Hazrat Rasoul Akram Hospital, Tehran University of Medical Sciences, Tehran, Iran.

3 Department of Radiology, Shohada-E-Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Abstract

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

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