title: Colorectal anatomy in adults at computed tomography colonography: normal distribution and the effect of age, sex, and body mass index.
abstract: OBJECTIVE
  Computed tomography colonography (CTC) is an accurate tool for assessing the large intestinal anatomy. Our aims were to determine the normal distribution of in vivo colorectal anatomy and to investigate the effect of age, sex, and body mass index (BMI) on colorectal length.
  
  
  METHODS
  Asymptomatic adults who underwent primary CTC examination at a single institution over an 8-month period were evaluated. The interactive three-dimensional map was used to determine total and segmental lengths and number of acute-angle flexures. The two-dimensional multiplanar display was used to measure luminal diameters. The effects of age, sex, and BMI on colorectal lengths were examined.
  
  
  RESULTS
  The study cohort consisted of 505 consecutive adults (266 women, mean age 56.6 years). Mean total colorectal length was 189.5 +/- 26.3 cm and mean number of acute-angle flexures was 10.9 +/- 2.4. Total length for older adults (> 60 years) did not significantly differ from those who were younger than 60 years ( P = 0.22), although the transverse colon was significantly longer in older adults ( P = 0.04). Women had significantly longer colons than men (193.3 cm vs. 185.4 cm, P = 0.002), whereas overweight adults (BMI > 25) had significantly shorter colons compared with those with BMI <or= 25 (187.2 cm vs. 194.5 cm, P = 0.005). Differences in total length were predominately due to differences in the transverse colon.
  
  
  CONCLUSIONS
  Our results define the normal distribution of colorectal anatomy in an asymptomatic adult cohort, and may help to facilitate both colonoscopy training efforts and design of novel endoscopic devices. The transverse colon was the major determinant in length differences according to age, sex, and BMI, and was significantly longer in older adults, women, and thinner adults, respectively.
authors: Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
authors: M A
authors: MA
authors: Khashab
authors: P J
authors: PJ
authors: Pickhardt
authors: D H
authors: DH
authors: Kim
authors: D K
authors: DK
authors: Rex
mesh_terms: D000367:Age Factors; D015992:Body Mass Index; D003106:Colon / Q000033:anatomy & histology*; D044684:Colon, Transverse; D023881:Colonography, Computed Tomographic; D003113:Colonoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016011:Normal Distribution; D012007:Rectum / Q000033:anatomy & histology*; D012737:Sex Factors