title: Detection of rectal cancer and response to concurrent chemoradiotherapy by proton magnetic resonance spectroscopy.
abstract: BACKGROUND
  To diagnose rectal cancer and monitor treatment response after preoperative concurrent chemoradiotherapy (CCRT) in rectal cancer patients using proton-1 magnetic resonance spectroscopy ((1)H-MRS).
  
  
  METHODS
  We enrolled 134 rectal cancer patients before treatment, of whom 34 underwent preoperative CCRT and follow-up MR spectroscopy before surgery. (1)H-MRS was performed using a six-channel phased-array coil at 3.0 T. We evaluated the presence of a choline peak at 3.2 ppm, and lipid peaks at 0.9 and 1.3 ppm, and glutamine and glutamate peaks at 2.1-2.3 and 2.7 ppm seen at two TEs (40 and 135 ms). We divided MR spectra patterns into two groups (A and B).
  
  
  RESULTS
  A choline peak at 3.2 ppm seen in both TEs was characteristic for rectal cancer before treatment. Of 103 patients, 55 (53%) showed an elevated choline peak before treatment (type A). Type A spectra were seen in 68% of patients (23/34) before preoperative CCRT. After CCRT, the choline peak disappeared, resulting in only the lipid peak at 1.3 ppm (type B) in 97% of patients (33/34).
  
  
  CONCLUSIONS
  We optimized a localized in vivo(1)H-MRS method for detection of rectal adenocarcinoma and monitoring treatment response after preoperative CCRT. The method appears to be a promising and feasible noninvasive modality.
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul, South Korea.
authors.forename: Min Ju
authors.initials: MJ
authors.lastname: Kim
authors.forename: Soon Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Seung Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Ho Kyung
authors.initials: HK
authors.lastname: Chun
authors.forename: Seong Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Hyo Keun
authors.initials: HK
authors.lastname: Lim
authors.forename: Seong Hyeon
authors.initials: SH
authors.lastname: Yun
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry / Q000175:diagnosis* / Q000628:therapy; D000328:Adult; D000368:Aged; D059248:Chemoradiotherapy; D002794:Choline / Q000032:analysis; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000628:therapy
chemical_list: D002794:Choline