Accuracy of Diffusion Weighted MRI in Prediction of Metastasis to Cervical Lymph Nodes in Oral Cancer Patients at a Tertiary Care Center in Jaipur.

Abstract

Aim:- To find out Sensitivity, Specificity, Accuracy, Positive and Negative predictive value of Diffusion weighted MRI in the prediction of metastasis in enlarged cervical lymph nodes in oral cancer patients on the basis of diffusion restriction and ADC values.

Material & methods: 70 patients with biopsy proven oral cancer with enlarged neck nodes were included in this study and underwent clinical and MRI examination. MRI was performed on PHILIPS INGENIA 3 TESLA MRI. Diffusion-weighted MR images were obtained at b factors of 0, 500, and 1,000 sec/mm². Prediction of metastasis to cervical lymph nodes was done on the basis of diffusion restriction and ADC values. All patients underwent Neck dissection and the final diagnosis was made by histopathology. Statistical analysis was applied to find out the sensitivity, specificity, PPV, NPV and diagnostic accuracy. P-value < 0.05 was taken as significant.

Results: Cervical lymph node metastasis was found in 38 out of 70 cases (54.28%) with the most frequent involvement of level I lymph nodes (52.86%). The mean ADCs value for malignant and benign lymph nodes was 0.87±0.21x10^-3 mm²/s and 1.31+/-0.20 x10^-3 mm²/s respectively.  Sensitivity, specificity, accuracy, PPV and NPV of Diffusion Weighted MRI in predicting cervical lymph nodal metastasis was 97.36%, 90.62%, 94.28%, 92.5% and 96.66% respectively when compared histopathologically.

Conclusion: Benign or malignant cervical lymph nodes can be differentiated on diffusion-weighted imaging of MRI on the basis of diffusion restriction and their ADC values concluding that diffusion imaging could be considered an important supportive tool for detecting malignancy in enlarged cervical lymph nodes.

Keywords: Apparent diffusion coefficient, Diffusion Weighted MRI, Oral Cancer