Differentiation of benign and malignant cervical lymph nodes on MRI with special emphasis on DWI

Aim and objectives: Evaluation of cervical lymph nodes with MRI, utility of DWI in differentiation of benign and malignant cervical lymph nodes.Methods: Prospective study was carried out on 71 patients of cervical lymphadenopathy in Dr. D.Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune over a period of two years. Patients were evaluated with Siemens MAGNETOM Avanto 1.5 T MRI machine. Characteristics of cervical lymph nodes on T1WI, T2WI, STIR and Diffusion weighted images with ADC values were studied. Comparison was made with histopathological reports to study accuracy of MRI DWI in differentiating benign and malignant lymph nodes. Results: Out of the total 71 cases, 41 cases were of benign lymph nodes and 30 cases were of malignant lymph nodes. Characteristics of lymph nodes were studied on MRI. Malignant lymph nodes showed diffusion restriction with corresponding low ADC values. Mean ADC value of benign lymph nodes was 1.1×10-3mm2/s (±0.9 SD) and for malignant lymph nodes was 0.7×10-3mm2/s (±0.2 SD).The suggested ADC cut off value in our study for differentiating benign from malignant lymph nodes was to be 0.93×10-3 mm2/s. Conclusion: Diffusion weighted imaging (DWI) is an important non-invasive diagnostic method for differentiation of benign and malignant cervical lymph nodes in case of head, neck cancers.