Research Article High b-Value Diffusion MRI to Differentiate Recurrent Tumors from Posttreatment Changes in Head and Neck Squamous Cell Carcinoma: A Single Center Prospective Study Angela Acampora, 1 Gaetana Manzo, 2 Giacomo Fenza, 2 Giuseppina Busto, 3 Antonietta Serino, 2 and Andrea Manto 2 1 Department of Advanced Biomedical Sciences, Section of Radiology, University of Naples “Federico II”, Via Sergio Pansini 5, 80131 Naples, Italy 2 Department of Neuroradiology, Umberto I Hospital, Viale San Francesco 2, 84014 Nocera Inferiore, Italy 3 Department of Onco-Hematology, DEA Nocera-Pagani, Umberto I Hospital, Viale San Francesco 2, 84014 Nocera Inferiore, Italy Correspondence should be addressed to Andrea Manto; and.manto@libero.it Received 8 March 2016; Revised 30 April 2016; Accepted 12 May 2016 Academic Editor: Sotirios Bisdas Copyright © 2016 Angela Acampora et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Recently DW-MR Imaging has shown promising results in distinguishing between recurrent tumors and posttreatment changes in Head and Neck Squamous Cell Carcinoma (HNSSC). Aim of this study was to evaluate the diagnostic performances of DWI at high b-value (b = 2000 s/mm 2 ) compared to standard b-value (b = 1000 s/mm 2 ) and ADC ratio values (ADC ratio = ADC 2000 /ADC 1000 ×100) to diferentiate recurrent tumors from posttreatment changes afer treatment of HSNCC. 20 patients (16 M, 4 F) underwent MR Imaging between 2 and 16 months (mean 7) afer treatment. Besides morphological sequences, we performed single-shot echo- planar DWI at b = 1000 s/mm 2 and b = 2000 s/mm 2 , and corresponding ADC maps were generated (ADC 1000 and ADC 2000 , resp.). By considering contrast-enhanced T1-weighted images as references, ROIs were drawn in order to evaluate mean ADC 1000 , ADC 2000 , and ADC ratio . Te mean ADC 1000 and ADC 2000 in recurrent tumors were signifcantly lower than those in posttreatment changes ( = 0.001 and  = 0.016, resp.). Moreover, the mean ADC ratio between the two groups showed a statistically signifcant diference ( = 0.002). Sensitivity, specifcity, and accuracy of ADC ratio were 82.0%, 100%, and 90%, respectively, by considering an optimal cutof value of 65.5%. ADC ratio is a promising value to diferentiate between recurrent tumors and posttreatment changes in HNSCC and may be more useful than ADC 1000 and ADC 2000 . 1. Introduction Squamous cell carcinoma represents almost 90% of the head and neck tumors (HNSCC) and it shows diferent biological behaviors according to location [1]. Imaging techniques are commonly required in order to defne tumor’s locoregional extension [2]. Moreover MRI is increasingly becoming the preferred examination method as it provides additional information on tumor extension, muscles and lymph nodes involvement, and skull base and intracranial invasion. Te role of MRI can therefore modify the clinical staging and consequently therapeutical approach, which is multidisciplinary with surgery, radiation therapy, and/or chemotherapy. In these patients, however, even if treatment improves survival and quality of life, on the other hand, it can delay detection of residual or recurrent tumor in post- treatment follow-ups as surgery can modify anatomy and radiochemotherapy can result in edema, infammation, fbro- sis, and, sometimes, necrosis [3–5]. Conventional MR Imaging gives sometimes wrong infor- mation as postcontrast enhancement of a benign lesion may mimic a residual or a recurrent tumor, leading to an increased number of false positives and unnecessary surgical approaches. On the contrary, a recurrent tumor may not show enhancement afer the administration of contrast medium. Recently, DW (difusion-weighted) MR Imaging has shown promising results. DWI is based on the Brownian Hindawi Publishing Corporation BioMed Research International Volume 2016, Article ID 2865169, 9 pages http://dx.doi.org/10.1155/2016/2865169