Extracolonic findings at CT colonography

Computed tomography colonography: a retrospective analysis of outcomes of 2 years experience in a district general hospital

BACKGROUND

Colonoscopy is the gold-standard investigation for direct luminal visualization of the large bowel. Studies have shown the efficacy of computed tomography colonography (CTC) is equivalent to colonoscopy in both cancer and polyp detection.

METHODS

A retrospective review of patients undergoing CTC from January 2013 to October 2014 was performed. Patient demographics, indication for investigation, computed tomography findings, optical colonoscopy findings and histology results were recorded.

RESULTS

Seven hundred and fifty-eight CTC were performed. Three hundred and seventeen patients were male (42%) and 441 (58%) were female. Endoscopy was advised in 209 cases. One hundred and twenty (16%) were deemed suspicious for cancer of whom 96 (80%) had optical colonoscopy. A total of 12 colorectal cancers were detected. Potential polyps were noted in 58 cases (8%). Forty-four patients underwent endoscopy (75%) and 17 polyps confirmed (38%). Two patients had foci of invasive cancer histologically. Significant extracolonic findings were identified in 60%, including five cases of gastric carcinomas. The most common other findings were gallstones and hernias.

CONCLUSION

The rate of colorectal cancer detection in this study was 2%. The rate of biopsy proven cancer was 10% following a suspicious colonogram. Endoscopic correlation was not obtained in 20% of cases of radiological suspicion. CTC is as efficacious as optical colonoscopy for colorectal cancer and polyp detection.

Computed tomography colonography in 2014: an update on technique and indications

Twenty years after its introduction, computed tomographic colonography (CTC) has reached its maturity, and it can reasonably be considered the best radiological diagnostic test for imaging colorectal cancer (CRC) and polyps. This examination technique is less invasive than colonoscopy (CS), easy to perform, and standardized. Reduced bowel preparation and colonic distention using carbon dioxide favor patient compliance. Widespread implementation of a new image reconstruction algorithm has minimized radiation exposure, and the use of dedicated software with enhanced views has enabled easier image interpretation. Integration in the routine workflow of a computer-aided detection algorithm reduces perceptual errors, particularly for small polyps. Consolidated evidence from the literature shows that the diagnostic performances for the detection of CRC and large polyps in symptomatic and asymptomatic individuals are similar to CS and are largely superior to barium enema, the latter of which should be strongly discouraged. Favorable data regarding CTC performance open the possibility for many different indications, some of which are already supported by evidence-based data: incomplete, failed, or unfeasible CS; symptomatic, elderly, and frail patients; and investigation of diverticular disease. Other indications are still being debated and, thus, are recommended only if CS is unfeasible: the use of CTC in CRC screening and in surveillance after surgery for CRC or polypectomy. In order for CTC to be used appropriately, contraindications such as acute abdominal conditions (diverticulitis or the acute phase of inflammatory bowel diseases) and surveillance in patients with a long-standing history of ulcerative colitis or Crohn's disease and in those with hereditary colonic syndromes should not be overlooked. This will maximize the benefits of the technique and minimize potential sources of frustration or disappointment for both referring clinicians and patients.

Detection of extracolonic pathologic findings with CT colonography: a discrete choice experiment of perceived benefits versus harms

PURPOSE

To determine the maximum rate of false-positive diagnoses that patients and health care professionals were willing to accept in exchange for detection of extracolonic malignancy by using computed tomographic (CT) colonography for colorectal cancer screening.

MATERIALS AND METHODS

After obtaining ethical approval and informed consent, 52 patients and 50 health care professionals undertook two discrete choice experiments where they chose between unrestricted CT colonography that examined intra- and extracolonic organs or CT colonography restricted to the colon, across different scenarios. The first experiment detected one extracolonic malignancy per 600 cases with a false-positive rate varying across scenarios from 0% to 99.8%. One experiment examined radiologic follow-up generated by false-positive diagnoses while the other examined invasive follow-up. Intracolonic performance was identical for both tests. The median tipping point (maximum acceptable false-positive rate for extracolonic findings) was calculated overall and for both groups by bootstrap analysis.

RESULTS

The median tipping point for radiologic follow-up occurred at a false-positive rate greater than 99.8% (interquartile ratio [IQR], 10 to >99.8%). Participants would tolerate at least a 99.8% rate of unnecessary radiologic tests to detect an additional extracolonic malignancy. The median tipping-point for invasive follow-up occurred at a false-positive rate of 10% (IQR, 2 to >99.8%). Tipping points were significantly higher for patients than for health care professionals for both experiments (>99.8 vs 40% for radiologic follow-up and >99.8 vs 5% for invasive follow-up, both P < .001).

CONCLUSION

Patients and health care professionals are willing to tolerate high rates of false-positive diagnoses with CT colonography in exchange for diagnosis of extracolonic malignancy. The actual specificity of screening CT colonography for extracolonic findings in clinical practice is likely to be highly acceptable to both patients and health care professionals. Online supplemental material is available for this article.

Colon capsule endoscopy: detection of colonic polyps compared with conventional colonoscopy and visualization of extracolonic pathologies

BACKGROUND

Conventional colonoscopy (CC) is the gold standard for diagnostic examination of the colon. However, the overall acceptance of this procedure is low due to patient fears of complications or embarrassment. Colon capsule endoscopy (CCE) represents a minimally invasive, patient-friendly procedure that offers complete visualization of the entire intestine.

OBJECTIVE

To assess the PillCam Colon 2 (Given Imaging Ltd, Israel) capsule with regard to feasibility, sensitivity and specificity for the detection of colonic pathologies and additional recorded extracolonic findings.

METHODS

CCE was performed before CC in patients indicated for CC for known or suspected colonic disease. The results of both techniques were compared with regard to polyp detection. Additionally, bowel preparation and extracolonic pathologies were analyzed.

RESULTS

Twenty-four patients (mean age 51.1 years) were included in the analysis. Visualization of the colon was complete in 23 CCs and 17 CCEs. No adverse events or major technical failures occurred. CC detected 47 polyps and CCE detected 43 polyps of any size (per-finding sensitivity 90.9%, specificity 67.6%). The accuracy of CCE in detecting polyp carriers was 81.5% (per-patient analysis). On average, the colon was adequately cleansed in 90.1% of patients. CCE identified esophageal, gastric and small bowel pathologies in seven (24%), nine (38%) and 14 (58%) patients, respectively.

CONCLUSIONS

CCE proved to be technically feasible and safe. Acceptable sensitivity and moderate specificity levels in polyp detection were recorded. Bowel preparation was adequate in most patients. Because extracolonic pathologies were effectively visualized, new indications for the PillCam Colon 2 may be defined.

When the non-contrast-enhanced phase is unnecessary in abdominal computed tomography scans? A retrospective analysis of 244 cases

Objective: To evaluate the necessity of the non contrast-enhanced phase in abdominal computed tomography scans. Materials and Methods: A retrospective, cross-sectional, observational study was developed, evaluating 244 consecutive abdominal computed tomography scans both with and without contrast injection. Initially, the contrast-enhanced images were analyzed (first analysis). Subsequently, the observers had access to the non-contrast-enhanced images for a second analysis. The primary and secondary diagnoses were established as a function of the clinical indications for each study (such as tumor staging, acute abdomen, investigation for abdominal collection and hepatocellular carcinoma, among others). Finally, the changes in the diagnoses resulting from the addition of the non-contrast-enhanced phase were evaluated. Results: Only one (0.4%; p > 0.999; non-statistically significant) out of the 244 reviewed cases had the diagnosis changed after the reading of non-contrast-enhanced images. As the secondary diagnoses are considered, 35 (14%) cases presented changes after the second analysis, as follows: nephrolithiasis (10%), steatosis (3%), adrenal nodule (0.7%) and cholelithiasis (0.3%). Conclusion: For the clinical indications of tumor staging, acute abdomen, investigation of abdominal collections and hepatocellular carcinoma, the non-contrast-enhanced phase can be excluded from abdominal computed tomography studies with no significant impact on the diagnosis.

Advances in CT Colonography for Colorectal Cancer Screening and Diagnosis

CT colonography (CTC) is a validated colorectal cancer test that provides an additional minimally-invasive screening option which is likely to be preferred by some patients. Important examination prerequisites include adequate colonic cleansing and distention. Tagging of residual material aids in the differentiation of true polyps from stool. Low radiation dose technique should be employed routinely for screening studies. Readers must be skilled in the use of both 2D and 3D interpretation methods.

Role of CT colonography in symptomatic assessment, surveillance and screening

INTRODUCTION

When 'whole colonic imaging' is indicated, clinicians must decide between optical colonoscopy, barium enema and CT colonography (CTC). CTC is a relatively new technique which has become increasingly accessible in the UK over the past 5 years. As radiologists have gained experience and scanning parameters have standardised, there have been substantial improvements in both the accuracy and safety of CTC.

METHODS

We review evidence from observational studies and randomised trials, and draw on expert opinion, to provide a comprehensive discussion of the current role of CTC in both symptomatic and asymptomatic individuals.

CONCLUSIONS

The emergence of CTC could soon entirely obviate the need for barium enema. CTC now has a complementary role alongside colonoscopy in symptomatic patients and a possible future role in colorectal cancer screening in the UK.