title: Depiction and local staging of rectal tumors: comparison of transrectal US before and after water instillation.
abstract: OBJECTIVE
  To determine whether transrectal ultrasonography (US) with intrarectal water instillation can improve the depiction and accuracy of US in local staging of rectal tumors.
  
  
  METHODS
  Between October 1999 and February 2002, 63 patients (mean age, 56 years; age range, 23-91 years) with 63 rectal tumors were evaluated with transrectal US before and after intrarectal water instillation. Transrectal US examinations were performed with a 7-10-MHz radial transducer. Immediately after the first transrectal US examination, the rectal lumen was filled with 50-150 mL of degassed water, and a second US examination was performed. All patients underwent surgery within 1 month after transrectal US. Depiction of the tumor was compared between the two methods. The McNemar test was used to compare the accuracy between the two techniques in local staging of the tumor by using pathologic findings in the resected specimen as the standard.
  
  
  RESULTS
  The tumors ranged from 0.5 to 8.0 cm (mean, 2.8 cm) as measured at pathologic evaluation. All 63 tumors were clearly depicted at transrectal US after water instillation, while only 42 (67%) of the tumors were depicted at transrectal US before water instillation. In the 42 tumors clearly depicted at transrectal US examinations both before and after water instillation, the accuracy of transrectal US in local tumor staging was significantly higher after water instillation (85.7% [36 of 42]) than before water instillation (57.1% [24 of 42]; P <.001).
  
  
  CONCLUSIONS
  Water instillation during transrectal US examination of rectal tumors improves the depiction and local staging of the tumors.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Kangnam-Ku, Seoul 135-710, Korea.
authors.forename: Sooah
authors.initials: S
authors.lastname: Kim
authors.forename: Hyo K
authors.initials: HK
authors.lastname: Lim
authors.forename: Soon Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Dongil
authors.initials: D
authors.lastname: Choi
authors.forename: Won Jae
authors.initials: WJ
authors.lastname: Lee
authors.forename: Seong Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Min Ju
authors.initials: MJ
authors.lastname: Kim
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Lim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016099:Endoscopy, Gastrointestinal; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007322:Instillation, Drug; D007723:Korea; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology*; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology*; D014463:Ultrasonography; D036761:Ultrasound, High-Intensity Focused, Transrectal; D014867:Water / Q000008:administration & dosage
chemical_list: D014867:Water