Value of Diffusion-Weighted and Perfusion-Weighted MR Imaging in Differentiation of Recurrent Tongue Carcinoma from Post-Treatment Changes

Background: Tongue carcinoma is characterized by high recurrence rate. Thus, post-treatment follow-up imaging is critically important. Advanced Magnetic Resonance Imaging (MRI) techniques can be employed for this purpose due to the limited accuracy of conventional MRI. Aim of Study: Evaluation of the value of Diffusion Weight-ed (DW) and perfusion weighted MRI implementation in the post-treatment follow-up of tongue carcinoma. Patients and Methods: This study was conducted on 23 patients on post-treatment follow-up of tongue carcinoma. They underwent DW-MRI and Dynamic Contrast Enhanced (DCE) perfusion T1-weighted MRI to differentiate between recurrent tumor and post-treatment changes. Apparent Diffu-sion Coefficient (ADC) was estimated, perfusion MR quali-tative and semiquantitative assessment was performed. Re-sulting data were compared to histopathologic characterization (n=18) and further clinical and radiological follow-up (n=5) which were considered as the reference standards. Results: The mean ADC value of recurrent tongue carci-noma (1.029±0.207 X 10–3mm2/s) was significantly lower (p < 0.001) than the mean ADC value of post-treatment changes (1.425±0.238 X 10–3mm2/s). The ADC threshold used for differentiating recurrent tumor from post-treatment changes was 1.175 X 10–3mm2/s with Area Under the Curve (AUC) of 0.938 and diagnostic accuracy of 82.6%. Among the DCE perfusion weighted MR parameters, the wash in rate and Area Under Gadolinium Curve (AUGC) displayed the highest diagnostic accuracy (73.9%) with thresholds of 18.65a.u/s and 126826.7m.M.s respectively. The combined use of both DW-MRI and perfusion weighted MRI showed the highest diagnostic accuracy. Conclusion: The DW MRI is a non-invasive technique providing accurate post-treatment follow-up assessment of tongue carcinoma. The perfusion weighted MRI provides lower diagnostic accuracy than DWI. The combined use of both techniques provides superior differentiation of tumor recurrence from post-treatment changes.