SURGICAL ONCOLOGY AND RECONSTRUCTION J Oral Maxillofac Surg 71:162-177, 2013 The Use of Multiple Time Point Dynamic Positron Emission Tomography/Computed Tomography in Patients With Oral/Head and Neck Cancer Does Not Predictably Identify Metastatic Cervical Lymph Nodes Eric R. Carlson, DMD, MD,* Josh Schaefferkoetter, BS,† David Townsend, PhD,‡ J. Michael McCoy, DDS,§ Paul D. Campbell Jr, MD, and Misty Long, RT(R)(N)¶ Purpose: To determine whether the time course of 18-fluorine fluorodeoxyglucose (18F-FDG) activity in multiple consecutively obtained 18 F-FDG positron emission tomography (PET)/computed tomography (CT) scans predictably identifies metastatic cervical adenopathy in patients with oral/head and neck cancer. It is hypothesized that the activity will increase significantly over time only in those lymph nodes harboring metastatic cancer. Patients and Methods: A prospective cohort study was performed whereby patients with oral/head and neck cancer underwent consecutive imaging at 9 time points with PET/CT from 60 to 115 minutes after injection with 18 F-FDG. The primary predictor variable was the status of the lymph nodes based on dynamic PET/CT imaging. Metastatic lymph nodes were defined as those that showed an increase greater than or equal to 10% over the baseline standard uptake values. The primary outcome variable was the pathologic status of the lymph node. Results: A total of 2,237 lymph nodes were evaluated histopathologically in the 83 neck dissections that were performed in 74 patients. A total of 119 lymph nodes were noted to have hypermetabolic activity on the 90-minute (static) portion of the study and were able to be assessed by time points. When we compared the PET/CT time point (dynamic) data with the histopathologic analysis of the lymph nodes, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 60.3%, 70.5%, 66.0%, 65.2%, and 65.5%, respectively. Conclusions: The use of dynamic PET/CT imaging does not permit the ablative surgeon to depend only on the results of the PET/CT study to determine which patients will benefit from neck dissection. As such, we maintain that surgeons should continue to rely on clinical judgment and maintain a low threshold for executing neck dissection in patients with oral/head and neck cancer, including those patients with N0 neck designations. © 2013 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 71:162-177, 2013 *Professor and Chairman, Department of Oral and Maxillofacial Surgery, University of Tennessee Graduate School of Medicine and the University of Tennessee Cancer Institute, Knoxville, TN. †PhD Student, University of Tennessee Cancer Institute, Univer- sity of Tennessee Graduate School of Medicine, and Molecular Imaging and Tracer Development Program, Knoxville, TN. ‡Formerly, Director of Molecular Imaging and Tracer Develop- ment Program, Knoxville, TN; Currently, Director, Singapore Clin- ical Imaging Research Centre and Professor of Radiology, National University of Singapore, Singapore. §Professor, Departments of Pathology and Oral and Maxillofacial Surgery, University of Tennessee Graduate School of Medicine, Knoxville, TN. Assistant Professor, Department of Radiology, University of Ten- nessee Graduate School of Medicine, Knoxville, TN. ¶Chief PET/CT Research Technologist, University of Tennessee Cancer Institute, University of Tennessee Graduate School of Medicine, and Mo- lecular Imaging and Tracer Development Program, Knoxville, TN. Conflict of Interest Disclosures: The authors have honoraria with Hollingsworth, LLP and royalties from Wiley Blackwell Pub- lishing. Address correspondence and reprint requests to Dr Carlson: Department of Oral and Maxillofacial Surgery, University of Ten- nessee Medical Center, 1930 Alcoa Hwy, Ste 335, Knoxville, TN 37920; e-mail: ecarlson@mc.utmck.edu © 2013 American Association of Oral and Maxillofacial Surgeons 0278-2391/13/7101-0$36.00/0 http://dx.doi.org/10.1016/j.joms.2012.03.028 162