title: Individually optimized contrast-enhanced 4D-CT for radiotherapy simulation in pancreatic ductal adenocarcinoma.
abstract: OBJECTIVE
  To develop an individually optimized contrast-enhanced (CE) 4D-computed tomography (CT) for radiotherapy simulation in pancreatic ductal adenocarcinomas (PDA).
  
  
  METHODS
  Ten PDA patients were enrolled. Each underwent three CT scans: a 4D-CT immediately following a CE 3D-CT and an individually optimized CE 4D-CT using test injection. Three physicians contoured the tumor and pancreatic tissues. Image quality scores, tumor volume, motion, tumor-to-pancreas contrast, and contrast-to-noise ratio (CNR) were compared in the three CTs. Interobserver variations were also evaluated in contouring the tumor using simultaneous truth and performance level estimation.
  
  
  RESULTS
  Average image quality scores for CE 3D-CT and CE 4D-CT were comparable (4.0 and 3.8, respectively; P = 0.082), and both were significantly better than that for 4D-CT (2.6, P < 0.001). Tumor-to-pancreas contrast results were comparable in CE 3D-CT and CE 4D-CT (15.5 and 16.7 Hounsfield units (HU), respectively; P = 0.21), and the latter was significantly higher than in 4D-CT (9.2 HU, P = 0.001). Image noise in CE 3D-CT (12.5 HU) was significantly lower than in CE 4D-CT (22.1 HU, P = 0.013) and 4D-CT (19.4 HU, P = 0.009). CNRs were comparable in CE 3D-CT and CE 4D-CT (1.4 and 0.8, respectively; P = 0.42), and both were significantly better in 4D-CT (0.6, P = 0.008 and 0.014). Mean tumor volumes were significantly smaller in CE 3D-CT (29.8 cm3, P = 0.03) and CE 4D-CT (22.8 cm3, P = 0.01) than in 4D-CT (42.0 cm3). Mean tumor motion was comparable in 4D-CT and CE 4D-CT (7.2 and 6.2 mm, P = 0.17). Interobserver variations were comparable in CE 3D-CT and CE 4D-CT (Jaccard index 66.0% and 61.9%, respectively) and were worse for 4D-CT (55.6%) than CE 3D-CT.
  
  
  CONCLUSIONS
  CE 4D-CT demonstrated characteristics comparable to CE 3D-CT, with high potential for simultaneously delineating the tumor and quantifying tumor motion with a single scan.
authors: Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 and Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors: Wookjin
authors: W
authors: Choi
authors: Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors: Ming
authors: M
authors: Xue
authors: Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors: Barton F
authors: BF
authors: Lane
authors: Department of Radiation Oncology, Kyungpook National University School of Medicine, Daegu 41944, South Korea.
authors: Min Kyu
authors: MK
authors: Kang
authors: Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors: Kruti
authors: K
authors: Patel
authors: Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors: William F
authors: WF
authors: Regine
authors: Philips Healthcare, Highland Heights, Ohio 44143.
authors: Paul
authors: P
authors: Klahr
authors: Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors: Jiahui
authors: J
authors: Wang
authors: Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors: Shifeng
authors: S
authors: Chen
authors: Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors: Warren
authors: W
authors: D'Souza
authors: Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 and Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201.
authors: Wei
authors: W
authors: Lu
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000532:radiotherapy*; D003287:Contrast Media; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D009068:Movement; D015588:Observer Variation; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000532:radiotherapy*; D057285:Precision Medicine; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D047368:Tumor Burden / Q000528:radiation effects
chemical_list: D003287:Contrast Media