title: Change of maximum standardized uptake value slope in dynamic triphasic [18F]-fluorodeoxyglucose positron emission tomography/computed tomography distinguishes malignancy from postradiation inflammation in head-and-neck squamous cell carcinoma: a prospective trial.
abstract: OBJECTIVE
  To evaluate dynamic [(18)F]-fluorodeoxyglucose (FDG) uptake methodology as a post-radiation therapy (RT) response assessment tool, potentially enabling accurate tumor and therapy-related inflammation differentiation, improving the posttherapy value of FDG-positron emission tomography/computed tomography (FDG-PET/CT).
  
  
  METHODS
  We prospectively enrolled head-and-neck squamous cell carcinoma patients who completed RT, with scheduled 3-month post-RT FDG-PET/CT. Patients underwent our standard whole-body PET/CT scan at 90 minutes, with the addition of head-and-neck PET/CT scans at 60 and 120 minutes. Maximum standardized uptake values (SUV(max)) of regions of interest were measured at 60, 90, and 120 minutes. The SUV(max) slope between 60 and 120 minutes and change of SUV(max) slope before and after 90 minutes were calculated. Data were analyzed by primary site and nodal site disease status using the Cox regression model and Wilcoxon rank sum test. Outcomes were based on pathologic and clinical follow-up.
  
  
  RESULTS
  A total of 84 patients were enrolled, with 79 primary and 43 nodal evaluable sites. Twenty-eight sites were interpreted as positive or equivocal (18 primary, 8 nodal, 2 distant) on 3-month 90-minute FDG-PET/CT. Median follow-up was 13.3 months. All measured SUV endpoints predicted recurrence. Change of SUV(max) slope after 90 minutes more accurately identified nonrecurrence in positive or equivocal sites than our current standard of SUV(max) ≥2.5 (P=.02).
  
  
  CONCLUSIONS
  The positive predictive value of post-RT FDG-PET/CT may significantly improve using novel second derivative analysis of dynamic triphasic FDG-PET/CT SUV(max) slope, accurately distinguishing tumor from inflammation on positive and equivocal scans.
authors: Department of Radiation Oncology, University of Iowa, Iowa City, Iowa. Electronic address: carryn-anderson@uiowa.edu.
authors: Carryn M
authors: CM
authors: Anderson
authors: Department of Radiation Oncology, University of Iowa, Iowa City, Iowa.
authors: Tangel
authors: T
authors: Chang
authors: Department of Nuclear Medicine, University of Iowa, Iowa City, Iowa.
authors: Michael M
authors: MM
authors: Graham
authors: Department of Radiation Oncology, University of Iowa, Iowa City, Iowa.
authors: Michael D
authors: MD
authors: Marquardt
authors: Department of Biostatistics, University of Iowa, Iowa City, Iowa.
authors: Anna
authors: A
authors: Button
authors: Department of Biostatistics, University of Iowa, Iowa City, Iowa.
authors: Brian J
authors: BJ
authors: Smith
authors: Department of Nuclear Medicine, University of Iowa, Iowa City, Iowa.
authors: Yusuf
authors: Y
authors: Menda
authors: Department of Radiation Oncology, University of Iowa, Iowa City, Iowa.
authors: Wenqing
authors: W
authors: Sun
authors: Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa.
authors: Nitin A
authors: NA
authors: Pagedar
authors: Department of Radiation Oncology, University of Iowa, Iowa City, Iowa.
authors: John M
authors: JM
authors: Buatti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000532:radiotherapy / Q000556:secondary; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000532:radiotherapy; D006801:Humans; D033162:Incidental Findings; D007249:Inflammation / Q000000981:diagnostic imaging* / Q000378:metabolism; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008482:Mediastinum; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000378:metabolism; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D050397:Radiotherapy, Intensity-Modulated; D012044:Regression Analysis; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging / Q000378:metabolism; D018709:Statistics, Nonparametric; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18