CT colonography for longitudinal in-vivo assessment of colonic lengthening in middle-age and older adults.

BACKGROUND

Although a general trend for longer colons among older adults has been observed, longitudinal demonstration of intra-patient elongation is lacking. We assessed colonic length at serial CT colonography (CTC), which allows for precise length measurement over time.

METHODS

Longitudinal CTC evaluation (mean time interval, 12.8 years; range, 11.6-16.6 years) in 100 asymptomatic adults (mean age, 54.2 years at index study; 50 men, 50 women) were analyzed using a dedicated software system (V3D Colon, Viatronix). Segmental and total colonic lengths were obtained at interactive 2D and 3D review utilizing the automated luminal centerline.

RESULTS

Mean total colonic length increased from 198.1 cm at index CTC to 205.7 cm at follow-up (p < 0.001), corresponding to an annual increase of 0.6 ± 1.2 cm/year. The corresponding median colonic length increased from 191.5 cm to 202.0 cm. Intraperitoneal segments suspended by a mesentery accounted for 80% (6.1 cm) of the average overall 7.6 cm elongation, including a mean increase of 2.1 cm in the sigmoid colon and 4.0 cm in the transverse colon. There was no significant net length change for the extraperitoneal segments (rectum and retroperitoneal colon). Women had a longer colon at initial CTC on average (202.1 cm vs. 194.0 cm) but mean length was similar at final CTC (205.4 cm vs. 206.1 cm) given the increased rate of interval elongation in men (0.88 cm/year in men vs. 0.31 cm/year in women).

CONCLUSION

Longitudinal CTC showed a mean age-related increase in colonic length of greater than 7 cm per decade in middle-age and older adults. The intraperitoneal colonic segments (transverse > sigmoid) accounted for most of this elongation, whereas the more fixed extraperitoneal segments showed no significant net length increase.