CT colonography: implementation, indications, and technical performance - a follow-up national survey.

BACKGROUND: Computed tomography colonography (CTC) is an accepted complement or alternative to optical colonoscopy (OC) but its implementation is incompletely analyzed, and technical performance varies between centers. PURPOSE: To evaluate implementation, indications, and technical performance of CTC in Sweden and to evaluate compliance to international guidelines. MATERIAL AND METHODS: A structured, self-assessed questionnaire regarding implementation and technical performance of CTC was sent to all eligible radiology departments in Sweden. Eighty-six out of 89 departments replied. Comparisons were made with similar national surveys from 2004 and 2009. RESULTS: The number of centers performing CTC gradually increased from 23 in 2004 to 77 in 2016. In parallel, centers performing barium enema (BE) examinations have decreased from 89 in 2004 to 13 in 2016. Main reasons stated for still performing BE were lack of resources regarding CTC/OC. Main reasons for not performing CTC were lack of suitable software, lack of machine/reading time, and lack of experience. The majority of centers follow international CTC guidelines. An important exception is fecal tagging, which was implemented in only 63% of the centers. Incomplete OC remains a major indication for CTC, while preoperative CTC in colorectal cancer and follow-up after diverticulitis have emerged as new indications. CONCLUSION: CTC today is well implemented in routine healthcare but still lacking in capacity. Indications have expanded over time, and most departments perform "state of the art" CTC, although fecal tagging is incompletely implemented.

ACR Appropriateness Criteria colorectal cancer screening.

Colorectal cancer is the third leading cause of cancer deaths in the United States. Most colorectal cancers can be prevented by detecting and removing the precursor adenomatous polyp. Individual risk factors for the development of colorectal cancer will influence the particular choice of screening tool. CT colonography (CTC) is the primary imaging test for colorectal cancer screening in average-risk individuals, whereas the double-contrast barium enema (DCBE) is now considered to be a test that may be appropriate, particularly in settings where CTC is unavailable. Single-contrast barium enema has a lower performance profile and is indicated for screening only when CTC and DCBE are not available. CTC is also the preferred test for colon evaluation following an incomplete colonoscopy. Imaging tests including CTC and DCBE are not indicated for colorectal cancer screening in high-risk patients with polyposis syndromes or inflammatory bowel disease. This paper presents the updated colorectal cancer imaging test ratings and is the result of evidence-based consensus by the ACR Appropriateness Criteria Expert Panel on Gastrointestinal Imaging. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Computed tomography (CT) colonography with CT arteriography and venography for the workup of intestinal transplant candidates.

Prior to intestinal transplantation, prospective candidates must undergo a series of radiologic examinations to address a variety of clinical issues. To date, little literature exists to guide physicians in this preoperative assessment. Multiple imaging studies can provide overlapping information. We have developed a simple two- or three-test protocol to streamline the workup. Sixteen adult patients presented as potential intestinal transplant candidates to Georgetown University Hospital. All but two patients underwent the full protocol of a biphasic IV contrast-enhanced computed tomography (CT) scan of the chest, abdomen, and pelvis with rectal carbon dioxide, an upper gastrointestinal study with small bowel follow through, and fistulogram when appropriate. Three-dimensional (3-D) reconstructions of the vascular anatomy as well as the colon were also generated. A telephone survey to other transplant centers was additionally conducted to compare radiographic evaluations. Overall, 15 of the 16 scans were diagnostic. One patient required a barium enema. Mean examinations per patient was 2.4. Only one of seven other centers was performing CT colonography in prospective intestinal transplant candidates. Our protocol provided all the necessary anatomic information needed to evaluate prospective transplant candidates. CT colonography with angiography is a suitable alternative to more time-consuming radiological studies.

Evaluation of two minimal-preparation regimes for CT colonography: optimising image quality and patient acceptability.

OBJECTIVE: To compare a 2 day bowel preparation regime of barium, iodine and a mild stimulant laxative with a 1 day iodine-only regime for CT colonography (CTC). METHODS: 100 consecutive patients underwent CTC. The first 50 patients (Regime 1) ingested 1 bisacodyl tablet twice a day 3 days before CTC and 1 dose each of 50 ml of barium and 20 ml of iodinated contrast per day starting 2 days before CTC. The second 50 patients (Regime 2) ingested 3 doses of iodinated contrast over 24 h prior to CTC. Volumes of residual stool and fluid, and the effectiveness of stool and fluid tagging, were graded according to methods established by Taylor et al (Taylor S, Slaker A, Burling D, Tam E, Greenhalgh R, Gartner L, et al. CT colonography: optimisation, diagnostic performance and patient acceptability of reduced-laxative regimens using barium-based faecal tagging. Eur Radiol 2008; 18: 32-42). A 3 day low-residue diet was taken by both cohorts. Questionnaires rating the side-effects and burden of the bowel preparation were compared to a control cohort of patients undergoing barium enema. RESULTS: The proportion of colons producing none/scattered stool (score 1) was 90.3% with Regime 1 and 65.0% with Regime 2 (p<0.005). Any residual stool was significantly better tagged with Regime 1 (score 5), with 91.7% of Regime 1 exhibiting optimum tagging vs 71.3% of Regime 2 (p<0.05). No significant differences in side-effects between the bowel preparation regimes for CTC were elicited. Bowel preparation for barium enema was tolerated significantly worse than both of the CTC bowel preparation regimes. CONCLUSION: Regime 1, containing a 3 day preparation of a mild laxative, barium and iodine, produced a significantly better prepared colon, with no difference in patient acceptability.

CT colonography standards.

Computed tomography (CT) colonography is the established successor to the barium enema for the detection of colonic neoplasia due to superior performance and patient experience. Consequently, CT colonography is widely disseminated across Western populations and increasingly provided by both subspecialist and general radiologists alike. As a result, CT colonography is now part of the core training curriculum for radiology in the UK. However, study data shows wide performance gaps between centres and between individuals of differing experience, which is perhaps unsurprising given the complexity of the CT colonography technique and interpretation. This article summarizes the background, evolution and recommendations of the CT colonography standards document (Appendix) developed by the International CT Colonography Standards Collaboration, which included highly experienced radiologists, radiographers, gastroenterologists, and screening experts. These standards are intended to guide and support radiology teams across the world by promoting methods for improving the quality of CT colonography technique and the patient experience.

Audit of the introduction of CT colonography for detection of colorectal carcinoma in a non-academic environment and its implications for the national bowel cancer screening programme.

AIM: To compare the sensitivity of double-contrast barium enema (DCBE) with computed tomography colonography (CTC) to determine whether CTC is superior for the detection of colorectal cancer (CRC) locally, and to compare the results to those of a national barium enema audit. MATERIALS AND METHODS: All patients undergoing diagnostic DCBE or CTC between January 2003 and December 2005 were identified from the picture archiving communication system (PACS). Patients with a confirmed diagnosis of CRC were identified from the local cancer registry. Patients who were not diagnosed as having CRC on imaging were assumed true negatives if they were not listed in the cancer registry by December 2007, giving a minimum of 2 years follow-up. DCBE and CTC reports of all patients with CRC were analysed, and cancer detection was considered to have occurred (positive test result) if the report stated the definite presence of CRC or possible CRC requiring further investigation. RESULTS: 2520 DCBEs and 604 CTCs were included. Twenty-one of 33 patients with CRC were detected using DCBE (incidence 1.31%, sensitivity 63.7%). Thirty-two of 33 patients with CRC were -detected using CTC (incidence 5.46%, sensitivity 97.7%). CONCLUSION: CTC is more sensitive for the detection of CRC, and its introduction in a district general hospital is justified. However, there has been a consequent decline in DCBE sensitivity, which, if reflected nationally, suggests CTC is the preferential screening test for CRC.

CT colonography: optimisation, diagnostic performance and patient acceptability of reduced-laxative regimens using barium-based faecal tagging.

To establish the optimum barium-based reduced-laxative tagging regimen prior to CT colonography (CTC). Ninety-five subjects underwent reduced-laxative (13 g senna/18 g magnesium citrate) CTC prior to same-day colonoscopy and were randomised to one of four tagging regimens using 20 ml 40%w/v barium sulphate: regimen A: four doses, B: three doses, C: three doses plus 220 ml 2.1% barium sulphate, or D: three doses plus 15 ml diatriazoate megluamine. Patient experience was assessed immediately after CTC and 1 week later. Two radiologists graded residual stool (1: none/scattered to 4: >50% circumference) and tagging efficacy for stool (1: untagged to 5: 100% tagged) and fluid (1: untagged, 2: layered, 3: tagged), noting the HU of tagged fluid. Preparation was good (76-94% segments graded 1), although best for regimen D (P = 0.02). Across all regimens, stool tagging quality was high (mean 3.7-4.5) and not significantly different among regimens. The HU of layered tagged fluid was higher for regimens C/D than A/B (P = 0.002). Detection of cancer (n = 2), polyps > or =6 mm (n = 21), and < or =5 mm (n = 72) was 100, 81 and 32% respectively, with only four false positives > or =6 mm. Reduced preparation was tolerated better than full endoscopic preparation by 61%. Reduced-laxative CTC with three doses of 20 ml 40% barium sulphate is as effective as more complex regimens, retaining adequate diagnostic accuracy.

CT colonography versus colonoscopy in the follow-up of patients after diverticulitis - a prospective, comparative study.

AIM: To assess whether computed tomography colonography (CTC) is a viable alternative to colonoscopy or double contrast barium enema in the follow-up of patients after diverticulitis. MATERIAL AND METHODS: Fifty patients underwent CTC followed immediately by colonoscopy. Results were blinded to the examiners. Findings of diverticular disease and patient acceptance were evaluated. RESULTS: Bowel preparation and distension were good in the majority of CTC and colonoscopy examinations. Diverticular disease was found in 96% of patients at CTC and in 90% at colonoscopy. The rate of agreement between CTC and colonoscopy for diverticular findings in the sigmoid colon was good (kappa=0.64). No complications were seen. Patients found colonoscopy more uncomfortable (p<0.03), more painful (p<0.001), and more difficult (p<0.01) than CTC. Of the patients favouring one examination, 74% preferred CTC. CONCLUSION: CTC appears to have a better diagnostic potential for imaging of diverticular disease-specific findings, when compared with colonoscopy. Also, CTC was less uncomfortable and was preferred by a majority of patients. CTC seems to be a reasonable alternative in follow-up of patients with symptomatic diverticular disease.

Virtual colonoscopy training and accreditation: a national survey of radiologist experience and attitudes in the UK.

AIM: Expert consensus recommends directed training and possibly in the future, formal accreditation before independent virtual colonoscopy (VC) reporting. We surveyed radiologists' experience of VC training, compared with barium enema, and assessed attitudes towards accreditation. MATERIALS AND METHODS: A questionnaire was sent to 78 consultant radiologists from 72 centres (65 National Health Service hospitals; seven independent primary screening centres) offering a VC service. RESULTS: Fifty-four (69%) eligible radiologists responded. They had interpreted 18,152 examinations (range 3-1500) in total versus 232,350 (13 times more) barium enemas. Twenty-two (41%) deemed their VC training as inadequate [including five (45%) of screening centre radiologists], and only 14 (26%) had attended a training workshop due to lack of availability (54%) or financial/study leave constraints (24%). Eleven (20%) radiologists routinely double-reported VC examinations versus 37 (69%) barium enemas, yet 21 (39%) considered requirements for VC training were greater than barium enema. Thirty-eight (70%) favoured accreditation beyond internal audit for VC versus 15(28%) for barium enema. Of these 38, seven (18%) favoured "one-off," and 18 (47%) periodic testing, with 16 (42%) favouring external audit alone or in combination with testing. Overall, 42 (78%) considered specific accreditation for reporting screening examinations appropriate and 45 (83%) respondents preferred a national radiological organization to regulate such a scheme. CONCLUSION: There is wide variability in reporting experience and recommendations for VC training have not been widely adopted, in part due to limited access to dedicated workshops. UK radiologists are generally in favour of VC accreditation, governed by a national radiology organization.

European Society of Gastrointestinal and Abdominal Radiology (ESGAR): consensus statement on CT colonography.

Rapid clinical dissemination of CT colonography (CTC) is occurring in parallel with continued research into technique optimisation and diagnostic performance. A need exists therefore for current guidance as to basic prerequisites for effective clinical implementation. A questionnaire detailing CTC technique, analysis, training and clinical implementation was developed by the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) CTC committee and circulated to all faculty members of previous ESGAR "hands-on" CTC training courses. Responses were collated and a consensus statement produced. Of 27 invited to participate, 24 responded. Reasonable consensus was reached on bowel preparation, colonic distension, patient positioning, use of IV contrast and optimal scan parameters. Both primary 2D and primary 3D analysis were advocated equally, with some evidence that more experienced readers prefer primary 2D. Training was universally recommended, although there was no consensus regarding minimum requirements. CTC was thought superior to barium enema, although recommended for screening only in the presence of validated local experience. There was consensus that polyps 4 mm or less could be ignored assuming agreement from local gastroenterological colleagues. There is increasing consensus amongst European experts as to the current best practice in CTC.

CT colonography in a Korean population with a high residue diet: comparison between wet and dry preparations.

AIM: To compare wet and dry preparation methods for computed tomography colonography (CTC) in terms of preparation quality, interpretation time, and diagnostic performance for polyp detection in a population with a high residue diet. MATERIALS AND METHODS: Eighty-six patients were divided into two groups. Group 1 (n=24) received a wet preparation of 4l polyethylene glycol (PEG) solution, and group 2 (n=62) received a dry preparation of phosphor-soda. Abnormal findings, including polyps, and the time required to interpret the CTC images in both groups were documented by a radiologist. CTC findings were compared to those of colonoscopy as a reference standard. Two radiologists evaluated the quality of CTC with regard to residual fluid, faeces, and colonic distension using a four-point scale in consensus. Statistical differences for residual fluid, faeces, distensibility on CTC, and interpretation time between the two groups were analysed. The diagnostic performance of CTC in both groups was also compared. RESULTS: One-hundred and ninety polyps in 70 patients were identified using colonoscopy. Regarding the quality of images produced the wet preparation was significantly better than the dry preparation (p<0.05). The average interpretation time was significantly shorter for the wet group (11.7 min) than the dry group (16.4 min) (p<0.05). For per-patient analysis, the positive predictive value (PPV) was significantly better for the wet (100%) than the dry group (79.6%; p=0.025). Sensitivities and PPV for >or=10 mm polyps were comparable between two groups (p>0.05). CONCLUSION: In a population with a high-residue diet, CTC with wet preparation can be interpreted in a time-efficient manner and is comparable with CTC with dry preparation.

Comparison of radiologists' confidence in excluding significant colorectal neoplasia with multidetector-row CT colonography compared with double contrast barium enema.

The aim of this study was to compare the confidence of experienced radiologists in excluding colonic neoplasia with CT colonography (CTC) compared with barium enema. 78 patients (median age 70 years, range 61-87 years, 44 women) underwent same day CTC and barium enema. Two radiologists experienced in reporting barium enema assessed whether the examination had excluded a polyp 6 mm or greater as "yes", "probably" or "no" for each of 6 colonic segments. Two different radiologists experienced in CTC independently performed the same assessment on the CT datasets. Responses were compared using a paired exact test. Formal barium enema and CT reports were compared with any endoscopic examination performed within 1 year. Studies reporting polyps 6 mm+ in patients not subsequently undergoing endoscopy were reviewed by two independent observers. Radiologists stated they had confidently excluded a significant lesion in 314 (71%) and 382 (86%) of 444 segments with barium enema and CTC, respectively (p<0.001). Confidence was significantly higher with CTC in the in the descending and ascending colon (p = 0.02 and p<0.001, respectively), and caecum (p<0.001). 22 patients underwent some form of endoscopy. Of five patients with proven colorectal neoplasia (including two with cancer), CTC and barium enema correctly identified five and three, respectively. In 56 patients not undergoing endoscopy, CTC reported 17 polyps 6 mm+, of which 16 were retrospectively classified as definite or probable. 11 could not be identified on the barium enema, even in retrospect. Confidence in excluding polyps 6 mm or larger is significantly greater with CT colonography particularly in the proximal colon.

Intra-individual comparison of patient acceptability of multidetector-row CT colonography and double-contrast barium enema.

AIMS: To compare the subjective acceptability of CT colonography in comparison with barium enema in older symptomatic patients, and to ascertain preferences for future colonic investigation. MATERIALS AND METHODS: The study population comprised 78 persons aged 60 years or over with symptoms suggestive of colorectal neoplasia, who underwent CT colonography followed the same day by barium enema. A 25-point questionnaire was administered after each procedure and an additional follow-up questionnaire a week later. Responses were compared using Wilcoxon matched pairs testing, Mann-Whitney test statistics and binomial exact testing. RESULTS: Participants suffered less physical discomfort during CT colonography (p = 0.03) and overall satisfaction was greater compared with barium enema (p = 0.03). On follow-up, respondents reported significantly better tolerance of CT colonography (p = 0.002), and were less prepared to undergo barium enema again (p < 0.001). Of 52 subjects expressing an opinion, all preferred CT to barium enema. CONCLUSION: Patient satisfaction was higher with CT colonography than barium enema. CT colonography caused significantly less physical discomfort and was overwhelmingly preferred by patients.

Computerized tomography colonography.

First introduced a decade ago, computerized tomography (CT) colonography (virtual colonoscopy) is emerging as an important radiologic investigation for colorectal neoplasia, with diagnostic performance likely exceeding barium enema and comparable with optical colonoscopy. Employing state-of-the-art multislice technology, CT colonography allows a complete examination of the colon and surrounding organs in less than 30 seconds. This article reviews current techniques, indications, comparison with existing technologies, and diagnostic performance. Although already widely disseminated, important future developments, such as prepless bowel cleansing (laxative free) and computer-aided diagnosis, may establish CT colonography as the preferred first-line, whole-colon investigation.