title: Does contrast enhancement on CT suggest tumor response for chemotherapy in small cell carcinoma of the lung?
abstract: OBJECTIVE
  The purpose of this article is to assess the correlation between contrast enhancement on CT and the tumor reduction ratio in small cell carcinoma of the lung after first-line chemotherapy.
  
  
  METHODS
  Twenty-eight patients with small cell carcinoma of lung underwent preenhancement and postenhancement CT scans before and after first-line chemotherapy, followed by second-line chemotherapy in 7 patients who had relapsed. The authors retrospectively analyzed the correlation between the tumor reduction ratio and the CT numbers of contrast enhancement in each case by multiple regression analysis using SPSS.
  
  
  RESULTS
  The mean tumor-reduction ratio was 58.2 +/- 43.2% after first-line chemotherapy, and the mean CT enhancement was 33.2 +/- 11.0 Hounsfield units (HU). The correlation coefficient between the tumor reduction ratio and the CT numbers of contrast enhancement was 0.57 (r = 0.32), and p value was < 0.002. After chemotherapy, more than 90% tumor reduction was seen in 11 patients. They revealed an average 41.9 +/- 7.6 HU tumor enhancement. Less than 50% tumor reduction was seen in 10 patients. They revealed an average 26.2 +/- 7.9 HU tumor enhancement. If these criteria of 30 HU contrast enhancement and 80% tumor reduction ratio were applied as a guide for chemotherapy response, the sensitivity, specificity, positive predictive value, and negative predictive value would be calculated as 85.7%, 84.6%, 85.7%, and 84.6%, respectively.
  
  
  CONCLUSIONS
  In small cell carcinoma of the lung, it is statistically proven that the more enhanced tumor on CT, the better response to chemotherapy. Tumor enhancement of 30 HU is a suggestive guide for chemotherapy response in patients with small cell carcinoma.
authors.affiliation: Department of Radiology, Hanyang University Kuri Hospital, 249-1 Kyomoon-dong, Kuri-shi, Kyungki-do, Republic of Korea.
authors.forename: Jung-Bin
authors.initials: JB
authors.lastname: Choi
authors.forename: Choong-Ki
authors.initials: CK
authors.lastname: Park
authors.forename: Dong Woo
authors.initials: DW
authors.lastname: Park
authors.forename: Yongsoo
authors.initials: Y
authors.lastname: Kim
authors.forename: Young-Sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Yo Won
authors.initials: YW
authors.lastname: Choi
authors.forename: Seok Chol
authors.initials: SC
authors.lastname: Jeon
mesh_terms: D000368:Aged; D018288:Carcinoma, Small Cell / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D012074:Remission Induction; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media