Flexible Sigmoidoscopy and CT Colonography Screening: Patients' Experience with and Factors for Undergoing Screening-Insight from the Proteus Colon Trial

Purpose To compare the acceptability of computed tomographic (CT) colonography and flexible sigmoidoscopy (FS) screening and the factors predicting CT colonographic screening participation, targeting participants in a randomized screening trial. Materials and Methods Eligible individuals aged 58 years (n = 1984) living in Turin, Italy, were randomly assigned to be invited to screening for colorectal cancer with FS or CT colonography. After individuals who had died or moved away (n = 28) were excluded, 264 of 976 (27.0%) underwent screening with FS and 298 of 980 (30.4%) underwent CT colonography. All attendees and a sample of CT colonography nonattendees (n = 299) were contacted for a telephone interview 3-6 months after invitation for screening, and screening experience and factors affecting participation were investigated. Odds ratios (ORs) were computed by means of multivariable logistic regression. Results For the telephone interviews, 239 of 264 (90.6%) FS attendees, 237 of 298 (79.5%) CT colonography attendees, and 182 of 299 (60.9%) CT colonography nonattendees responded. The percentage of attendees who would recommend the test to friends or relatives was 99.1% among FS and 93.3% among CT colonography attendees. Discomfort associated with bowel preparation was higher among CT colonography than FS attendees (OR, 2.77; 95% confidence interval [CI]: 1.47, 5.24). CT colonography nonattendees were less likely to be men (OR, 0.36; 95% CI: 0.18, 0.71), retired (OR, 0.31; 95% CI: 0.13, 0.75), to report regular physical activity (OR, 0.37; 95% CI: 0.20, 0.70), or to have read the information leaflet (OR, 0.18; 95% CI: 0.08, 0.41). They were more likely to mention screening-related anxiety (mild: OR, 6.30; 95% CI: 2.48, 15.97; moderate or severe: OR, 3.63; 95% CI: 1.87, 7.04), erroneous beliefs about screening (OR, 32.15; 95% CI: 6.26, 165.19), or having undergone a recent fecal occult blood test (OR, 13.69; 95% CI: 3.66, 51.29). Conclusion CT colonography and FS screening are well accepted, but further reducing the discomfort from bowel preparation may increase CT colonography screening acceptability. Negative attitudes, erroneous beliefs about screening, and organizational barriers are limiting screening uptake; all these factors are modifiable and therefore potentially susceptible to interventions. (©) RSNA, 2017 Online supplemental material is available for this article

CT colonography: Preliminary assessment of a double-read paradigm that uses computer-aided detection as the first reader

Purpose: To compare diagnostic performance and time efficiency of double-reading first-reader computer-aided detection (CAD) (DR FR CAD) followed by radiologist interpretation with that of an unassisted read using segmentally un-blinded colonoscopy as reference standard. Materials and Methods: The local ethical committee approved this study. Written consent to use examinations was obtained from patients. Three experienced radiologists searched for polyps 6 mm or larger in 155 computed tomographic (CT) colonographic studies (57 containing 10 masses and 79 polyps >= 6 mm). Reading was randomized to either unassisted read or DR FR CAD. Data sets were reread 6 weeks later by using the opposite paradigm. DR FR CAD consists of evaluation of CAD prompts, followed by fast two-dimensional review for mass detection. CAD sensitivity was calculated. Readers' diagnoses and reviewing times with and without CAD were compared by using McNemar and Student t tests, respectively. Association between missed polyps and lesion characteristics was explored with multiple regression analysis. Results: With mean rate of 19 (standard deviation, 14; median, 15; range, 4-127) false-positive results per patient, CAD sensitivity was 90% for lesions 6 mm or larger. Readers' sensitivity and specificity for lesions 6 mm or larger were 74% (95% confidence interval [CI]: 65%, 84%) and 93% (95% CI: 89%, 97%), respectively, for the unassisted read and 77% (95% CI: 67%, 85%) and 90% (95% CI: 85%, 95%), respectively, for DR FR CAD (P = .343 and P = .189, respectively). Overall unassisted and DR FR CAD reviewing times were similar (243 vs 239 seconds; P = .623); DR FR CAD was faster when the number of CAD marks per patient was 20 or fewer (187 vs 220 seconds, P < .01). Odds ratio of missing a polyp with CAD decreased as polyp size increased (0.6) and for polyps visible on both prone and supine scans (0.12); it increased for flat lesions (9.1). Conclusion: DR FR CAD paradigm had similar performance compared with unassisted interpretation but better time efficiency when 20 or fewer CAD prompts per patient were generated. (C) RSNA, 201

TRIALS STUDY PROTOCOL Open Access

Population screening for colorectal cancer by flexible sigmoidoscopy or CT colonography: study protocol for a multicenter randomized tria

Adverse events of computed tomography colonography: an Italian National Survey

AIM: To retrospectively study the frequency and magnitude of complications associated with computed tomography (CT) colonography in clinical practice. METHODS: A questionnaire on complications of CT colonography was sent to Italian public radiology departments identified as practicing CT colonography with a reasonable level of training. The frequency of complications and possible risk factors were retrospectively determined. Responses were collated and row frequencies determined. A multivariate analysis of the factors causing adverse events was also performed. RESULTS: 40,121 examinations were performed in13 centers during the study period. No deaths were reported. Bowel perforations occurred in 0.02% (7 exams). All perforations were asymptomatic and occurred in patients undergoing manual insufflation. Five perforations (71%) occurred in procedures performed following a recent colonoscopy. There was no significant difference between perforations associated with rectal balloon (0.017%) and those that were not (0.02%). Complications related to vasovagal reaction (either with or without spasmolytic) occurred in 0.16% (63 exams). All vasovagal reactions resolved in less than 3h, without any sequelae. CONCLUSIONS: Perforation rate at CT colonography in Italy is comparable with elsewhere in the world, occurring regardless of the experience of radiology centers. Although the risk is very small, it may not be negligible when compared with the risk of diagnostic colonoscopy