@article {Razek1146, author = {A.A.K. Abdel Razek and A.Y. Kandeel and N. Soliman and H.M. El-shenshawy and Y. Kamel and N. Nada and A. Denewar}, title = {Role of Diffusion-Weighted Echo-Planar MR Imaging in Differentiation of Residual or Recurrent Head and Neck Tumors and Posttreatment Changes}, volume = {28}, number = {6}, pages = {1146--1152}, year = {2007}, doi = {10.3174/ajnr.A0491}, publisher = {American Journal of Neuroradiology}, abstract = {BACKGROUND AND PURPOSE: The purpose of this work was to evaluate whether diffusion-weighted MR imaging can be used in differentiating residual or recurrent head and neck tumors from postoperative or postradiation changes.MATERIALS AND METHODS: This study included 32 patients clinically suspected for recurrent head and neck tumor after surgery (n=3), radiation therapy (n=13), or both (n=16). Diffusion-weighted MR imaging was done by using a single-shot spin-echo echo-planar sequence. The apparent diffusion coefficient (ADC) value of the suspected lesion was calculated and correlated with pathologic results.RESULTS: Adequate diffusion-weighted MR images and ADC maps were obtained in 30 patients (93.8\%). The mean ADC value of residual or recurrent lesions (1.17 {\textpm} 0.33 {\texttimes} 10-3 mm2/s) was less than that of posttherapeutic changes (2.07 {\textpm} 0.25 {\texttimes} 10-3 mm2/s), and the difference was statistically significant (P \< .001). When an ADC value of 1.30 {\texttimes} 10-3 mm2/s was used as a threshold value for differentiation, the best results were obtained with an accuracy of 87\%, sensitivity of 84\%, specificity of 90\%, positive predictive value of 94\%, and negative predictive value of 76\%.CONCLUSIONS: Diffusion-weighted MR imaging with ADC measurement has promising results for differentiating residual or recurrent head and neck tumors from postoperative or postradiation changes.}, issn = {0195-6108}, URL = {https://www.ajnr.org/content/28/6/1146}, eprint = {https://www.ajnr.org/content/28/6/1146.full.pdf}, journal = {American Journal of Neuroradiology} }