title: Quantitative measurement of contrast enhancement of esophageal squamous cell carcinoma on clinical MDCT.
abstract: OBJECTIVE
  To investigate contrast-enhanced computed tomography (CECT) for discriminating esophageal squamous cell carcinoma (ESCC) from normal esophagus and evaluating outcomes within tumors after chemoradiotherapy (CRT).
  
  
  METHODS
  Sixty-four patients with surgical ESCC served as group A, and underwent thoracic contrast-enhanced scan with 16-section multidetector row CT 1 wk before surgery. Thirty-five patients with advanced ESCC receiving 4-wk CRT and showing response to CRT served as group B, and underwent CT scans similar with group A 4 wk after completion of CRT. In group A, differences in CT attenuation values (in HU) between the preoperative ESCC and background normal esophageal wall (delta CT(1)), or between different background normal esophageal walls (delta CT(2)) were compared. Furthermore, delta CT(1) between group A and B was also compared.
  
  
  RESULTS
  In group A, mean delta CT(1) was higher than delta CT(2) (23.86 ± 10.59 HU vs 6.24 ± 3.06 HU, P < 0.05). When a delta CT(1) of 10.025 HU was employed at a cut-off value to discriminate ESCC from normal esophagus, a sensitivity of 89.1% and specificity of 90.6% were achieved. Mean delta CT(1) was lower in group B than in group A (9.25 ± 10.86 vs 23.86 ± 10.59, P < 0.05), and a delta CT(1) of 15.45 HU was obtained at a cut-off value to assess the CRT changes with a sensitivity of 76.6% and specificity of 77.1%.
  
  
  CONCLUSIONS
  CECT might be a clinical technique for discriminating ESCC from normal esophagus, and evaluating outcome in the tumors treated with CRT.
authors.affiliation: Rui Li, Tian-Wu Chen, Li-Ying Wang, Li Zhou, Hang Li, Xiao-Li Chen, Chun-Ping Li, Xiao-Ming Zhang, Ru-Hui Xiao, Sichuan Key Laboratory of Medical Imaging, and Department of Radiology, Affiliated Hospital of North Sichuan Medical College, Nanchong 637000, Sichuan Province, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.forename: Tian-Wu
authors.initials: TW
authors.lastname: Chen
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.forename: Hang
authors.initials: H
authors.lastname: Li
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Chen
authors.forename: Chun-Ping
authors.initials: CP
authors.lastname: Li
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Zhang
authors.forename: Ru-Hui
authors.initials: RH
authors.lastname: Xiao