The value of diffusion-weighted MRI (DW-MRI) as a tool to differentiate between various tumors and inflammatory diseases in the head and neck region

Abstract

Objective: To retrospectively determine whether diffusion-weighted magnetic resonance imaging (DW-MRI) can help in differentiating between various tumors and inflammatory lesions in the head and neck. Materials/ methods: After obtaining ethics committee approval, a search was made in the radiology records for patients with diffusion-weighted MR imaging for inflammatory, benign and malignant lesions in the head and neck region, which were confirmed either by histopathology or by follow up for at least one year. Seventy-two patients were included in this study. The lesions were grouped into malignant lesions, comprising primary carcinomas (n=17), metastasis (n=12) and lymphoma (n=12), benign tumors (n=24), inflammation (n=4) and miscellaneous benign lesions (n=3). Diffusion was assessed qualitatively by visual analysis and quantitatively by measuring the apparent diffusion coefficient (ADC) values. Results: Benign lesions had higher ADC values than malignant lesions: The mean value for benign tumors was 1.46 x 10-3 mm 2 /sec and for inflammatory lesions 1.51 x 10-3 mm 2 /sec. Lymphomas showed a mean value of 0.56 x 10-3 mm 2 /sec. The values for carcinoma and metastasis were similar with 0.84 x 10-3 mm 2 /sec and 0.81 x 10-3 mm 2 /sec respectively. According to receiver operating characteristic (ROC) analysis, values higher than 1.03 x 10-3 mm 2 /sec were ideal for differentiation between benign lesions and malignant tumors with a sensitivity of 88% and specificity of 79%. Lymphomas had significantly lower ADC values than all other entities. Conclusion: DW-MRI can help in differentiation of inflammatory and benign lesions from malignant lesions of the head and neck.