Bowel habits and gender correlate with colon length measured by CT colonography

Purpose CT colonography enables three-dimensional measurement of colon length. However, previous studies using CT colonography have not examined the association with gender, age, physique, a history of laparotomy and bowel habits, all possible contributory factors to colon length. The aim of this study is to investigate factors associated with colon length. Materials and methods We conducted a post hoc analysis based on data obtained from a previous multi-center trial including 321 patients with positive fecal immunochemical tests who underwent CT colonography. Colon length was measured using a computer-generated center line and was divided at the iliac crest level into the distal and proximal colons. Bowel habits were classified into three groups: A—daily; B—once every 2 or 3 days; and C—less than once in 3 days. Statistical comparison was made using one-way ANOVA with Bonferroni’s correction. Results A total of 295 patients were analyzed. The entire colon length (cm, mean ± standard deviation) of individual patients was 150.3 ± 18.5 cm and ranged from 109.7 to 195.9 cm. The female colon was significantly longer than the male colon (154.3 ± 18.1 cm vs. 147.1 ± 18.3 cm; p = 0.022). Colon length showed trends associated with age (p = 0.18) and a history of laparotomy (p = 0.14). According to bowel habits, the entire colon measured 147.4 ± 17.9 in group A, 154.7 ± 18.5 in group B and 158.6 ± 18.3 in group C, and significant differences were observed for “A vs. C” (p = 0.002) and “A vs. B” (p = 0.014). In subgroup analysis by colon segment, the proximal colon trended similarly to the entire colon while there were no trends for the distal colon. Conclusions This study has clearly demonstrated that bowel habits and gender both correlate with the length of the entire colon measured by CT colonography, and in particular, the proximal colon. Secondary abstract Using CT colonography, we measured the colon length in 295 patients. The entire colon length was 150.3 ± 18.5 cm on average. Females and constipated (less frequent defecation) patients have a significantly longer colon, and in particular, the proximal colon. Colon length showed trends associated with age and a history of laparotomy.

TP1.2.4The incidence, implications and risk factors for extracolonic findings at CT colonography in a bowel screening population

Aim CT virtual colonoscopy (CTC) is increasingly relied upon in bowel screening programmes. Concern remains regarding the prevalence of incidental extra-colonic findings (ECF). The present study reports on the prevalence and implications of ECF as part of a UK bowel screening programme. Methods Reports for 400 consecutive CTCs carried out as part of the Scottish Bowel Screening Programme were examined. Intra and extracolonic findings were recorded using the CT Colonography Reporting and Data System (C-RADS). Medical records pertaining to ECF follow-up were examined. Cost analysis was performed. Results 394 patients were included. 146 (37%) were males. Median age was 65 years, median follow-up was 72 months (Range 32-110). 92 (23%) patients had CTC as their primary investigation, 302 (77%) patients underwent CTC due to failed colonoscopy. Overall, 244/394 (62%) patients had ECF with only 45/394 (11%) found to have colonic pathology. 65/394 (16%) had moderately or highly significant ECF, (C-RADS E3-4). Of the 244 patients with ECF, 59 (24%) underwent further investigation, estimated cost £17,589. The majority, 37/59 (63%) were found to have benign disease after follow-up. Conclusion ECF at CTC are more frequent than colonic findings. The majority of ECF investigated are found to be benign yet a quarter of ECF are further investigated at a cost to the health service and the patient. Clinicians should be judicial when ordering and consenting patients with regards ECF and its implications if CTC is considered. Particularly when the test is part of a public funded and voluntary screening programme.

TP1.2.2CT Colonography (CTC) Should be the ‘Gold Standard’ in Suspected Colonic Malignancy: Results of a Retrospective Cohort Study

Aim Colonoscopy is the ‘gold’ standard with CT Colonography (CTC) being an alternative to investigate symptoms of colorectal cancer (CRC). Colonoscopy is invasive and can be embarrassing and distressing for patients. This retrospective cohort study aimed to investigate the validity of CTC in patients with suspected CRC. Methods We retrospectively reviewed 815 electronic patient records for those undergoing CTC in a large teaching hospital, between 2013 and 2015. Demographic data in addition to specific data on indication for CTC, endoscopic evaluation and further radiological imaging was collected until 2018. Results Mean age of the cohort was 67 (21 - 93 years). 326 (40%) patients underwent lower GI endoscopy in the three months preceding CTC, whilst 90 (11%) patients underwent endoscopy in the year following CTC. 37 patients had a CT Colonography Reporting Data System score (C-RADS) of C4 suggesting a colonic malignancy. Of these 21 (57%) were confirmed CRC, others demonstrated benign pathology (32%) or were unit or lost to follow up (11%). 56 (7%) had C-RADS of E4 suggesting significant extracolonic findings, 6 (11%) of which were renal cell carcinomas. Only 2 patients went on to develop a colorectal malignancy within our follow up period. Conclusions This large retrospective cohort study demonstrates that CTC is a reliable and valid tool. The authors propose that CTC should be the first line investigation with endoscopy reserved for use as an adjunct for diagnosis.Despite the limitations of a retrospective review, we were able to generate large patient numbers in order to establish our outcomes.