Barium enema and endoscopy for the detection of colorectal neoplasia: sensitivity, specificity, complications and its determinants

Comparison of Linked Color Imaging and White Light Imaging Colonoscopy for Detection of Colorectal Adenoma Requiring Endoscopic Treatment: A Single-Center Randomized Controlled Trial

BACKGROUND

Linked color imaging (LCI) improves detection of colorectal neoplastic lesions during colonoscopy. However, polyps <5 mm in diameter often do not require resection, and the benefits of LCI are unclear for detection of colorectal polyps ≥5 mm that are indicated for endoscopic resection in clinical practice. This randomized controlled trial compared rates of detection of adenoma polyps, stratified by size, for LCI and white light imaging (WLI).

METHODS

We compared ADR (5 mm-) and PDR (5 mm-), which were defined as the proportion of patients with at least one adenoma or polyp with a diameter of 5 mm or larger in the LCI and WLI groups. Moreover, we estimated ADR and PDR for diameters between 5 and 10 mm (ADR (5-9 mm), PDR (5-9 mm) ) and for diameters larger than 10 mm (ADR (10 mm-), PDR (10 mm-) ).

RESULTS

Data from 594 patients (LCI, n=305; WLI, n=289) were analyzed. ADR (5 mm-) and PDR (5 mm-) were significantly higher in the LCI group than in the WLI group (ADR (5 mm-): P=0.016, PDR (5 mm-): P=0.020). In the assessment of adenoma and polyp size, ADR (5-9 mm) and PDR (5-9 mm) were significantly higher in the LCI group than in the WLI group, although no significant differences were seen in ADR (10 mm-) and PDR (10 mm-) between these groups.

CONCLUSIONS

Polyps ≥5 mm, which are indicated for endoscopic treatment, were more easily visualized with LCI mode than with WLI mode. The improvement in detection rate was obvious for polyps <10 mm, which are easier to miss.

Validation of Urinary Charged Metabolite Profiles in Colorectal Cancer Using Capillary Electrophoresis-Mass Spectrometry

This study aimed to validate and reanalyze urinary biomarkers for detecting colorectal cancers (CRCs). We previously conducted urinary metabolomic analyses using capillary electrophoresis-mass spectrometry and found a significant difference in various metabolites, especially polyamines, between patients with CRC and healthy controls (HC). We analyzed additional samples and confirmed consistency between the newly and previously analyzed data. In total, we included 36 HC, 34 adenoma (AD), and 214 CRC samples, which were used for subsequent analyses. Among the 132 quantified metabolites, 16 exhibited consistent differences in both datasets, which included polyamines, etc. Pathway analyses of the integrated data revealed significant differences in many metabolites, such as glutamine, and metabolites of the TCA (tricarboxylic acid cycle) and urea cycles. The discrimination ability of the combination of multiple metabolites among the three groups was evaluated, which yielded higher sensitivity than tumor markers. The Mann–Whitney test was employed to evaluate the prognosis predictivity of the assessed metabolites and the difference between the patients with or without recurrence, which yielded 16 significantly different metabolites. Among these 16 metabolites, 11 presented significant prognosis predictivity. These data indicated the potential of metabolite-based discrimination of patients with CRC and AD from HC and prognosis predictivity of the monitored metabolites.

Using whole disease modeling to inform resource allocation decisions: economic evaluation of a clinical guideline for colorectal cancer using a single model

OBJECTIVE

To assess the feasibility and value of simulating whole disease and treatment pathways within a single model to provide a common economic basis for informing resource allocation decisions.

METHODS

A patient-level simulation model was developed with the intention of being capable of evaluating multiple topics within National Institute for Health and Clinical Excellence's colorectal cancer clinical guideline. The model simulates disease and treatment pathways from preclinical disease through to detection, diagnosis, adjuvant/neoadjuvant treatments, follow-up, curative/palliative treatments for metastases, supportive care, and eventual death. The model parameters were informed by meta-analyses, randomized trials, observational studies, health utility studies, audit data, costing sources, and expert opinion. Unobservable natural history parameters were calibrated against external data using Bayesian Markov chain Monte Carlo methods. Economic analysis was undertaken using conventional cost-utility decision rules within each guideline topic and constrained maximization rules across multiple topics.

RESULTS

Under usual processes for guideline development, piecewise economic modeling would have been used to evaluate between one and three topics. The Whole Disease Model was capable of evaluating 11 of 15 guideline topics, ranging from alternative diagnostic technologies through to treatments for metastatic disease. The constrained maximization analysis identified a configuration of colorectal services that is expected to maximize quality-adjusted life-year gains without exceeding current expenditure levels.

CONCLUSIONS

This study indicates that Whole Disease Model development is feasible and can allow for the economic analysis of most interventions across a disease service within a consistent conceptual and mathematical infrastructure. This disease-level modeling approach may be of particular value in providing an economic basis to support other clinical guidelines.

Attendance at iron deficiency anaemia clinic: audit of outcomes 5 years on

AIM

To determine the long-term outcomes of patients in whom no initial cause for their anaemia is established.

METHOD

Six hundred and thirty-nine patients presenting to an iron deficiency anaemia pathway were prospectively entered onto a database. Initial assessment included haematological review, coeliac screen, oesophagogastroduodenoscopy and colonic imaging as per British Society of Gastroenterology guidelines. A 5-year audit of outcomes was undertaken using patient medical records and hospital laboratory databases.

RESULTS

A diagnosis was found initially in 266 (42%) patients, with 124 (19%) having a gastrointestinal (GI) luminal neoplasm, 54 (8%) of which were malignant. Twelve patients had a nonluminal or non-GI malignancy. Eighty-eight (14%) had benign upper GI bleeding and 23 (4%) had coeliac disease. One hundred and forty-three (22%) did not have confirmed iron deficiency anaemia on review of haematinics. Complete records were available for 595 (93%) patients at 5 years. Of the 373 patients in whom a cause was not initially diagnosed, 6 (2%) were ultimately diagnosed with a GI luminal malignancy and 18 (5%) with a nonluminal or non-GI malignancy. There was no difference in the incidence of malignancies between those with or without confirmed iron deficiency.

CONCLUSIONS

Most patients in whom no cause was found at initial investigation resolve on oral iron supplements. Patients with normal ferritin values had as high an incidence of GI malignancies as those with low values and should be investigated. In the over 50s if the anaemia remains after a course of iron further investigation is recommended as there is a significant incidence of both GI and non-GI pathology.

Colovaginal and colovesical fistulae: the diagnostic paradigm

BACKGROUND

Colovaginal and colovesical fistulae (CVF) are relatively uncommon conditions, most frequently resulting from diverticular disease or colorectal cancer. A high suspicion of a CVF can usually be obtained from an accurate clinical history. Demonstrating CVF radiologically is often challenging, and patients frequently undergo a multitude of investigations prior to definitive management. The aim of this study was to develop an algorithm for the investigation of suspected CVF in order to improve diagnosis and subsequent management.

METHODS

Thirty-seven patients from a single NHS Trust with a diagnosis of colovaginal or colovesical fistula were included in the study. Clinical records and imaging were reviewed retrospectively, and data on demographics, symptoms, investigations, management and outcome were collated.

RESULTS

A total of 87.5% patients with a colovesical fistula presented with pathognomic symptoms of faecaluria or pneumaturia. The commonest aetiologies were diverticular disease (72.9%), colonic and gynaecological neoplasia (10.8% each). Computerised tomography (CT) was the most frequently performed investigation (91.9%) and was most sensitive in detecting the fistula (76.5%) and underlying aetiology (94.1%). Colonoscopy was most sensitive in detecting an underlying colonic malignancy (100%). Resectional surgery was performed in 62.1% of cases, although morbidity and 1-year mortality was significant, with rates of 21.7 and 17.4%, respectively.

CONCLUSIONS

The diagnosis of CVF is predominately a clinical one, and patients with a suspected CVF are over-investigated. Investigations should be focused on determining aetiology rather than demonstrating the fistulous tract itself. We propose that, in the majority of cases, CT and lower gastrointestinal endoscopy should suffice.

Colorectal cancer detection: time to abandon barium enema?

OBJECTIVES

To assess the sensitivity of double contrast barium enema (DCBE) for diagnosing colorectal cancer (CRC).

DESIGN

Retrospective evaluation of DCBE performed in the 2 years prior to diagnosis of CRC.

SETTING

Teaching hospital in Cambridge, UK.

PATIENTS

1310 consecutive cases of CRC identified from cancer registry data.

INTERVENTIONS

DCBE and colonoscopy.

MAIN OUTCOME MEASURES

Sensitivity of DCBE for diagnosing CRC.

RESULTS

215 patients had undergone a DCBE within the 2 years prior to diagnosis with CRC. After excluding those reported as inadequate, 37 of these were reported as normal, giving a sensitivity of 83% (81-85%).

CONCLUSIONS

The performance of DCBE is inadequate for the exclusion of CRC. Expansion of colonoscopy and CT colonography capacity is urgently required nationally so that DCBE can finally be abandoned as a firstline test in patients at risk of CRC.

Colorectal cancer screening

Colorectal cancer (CRC) constitutes the second leading cause of death from cancer in the United States. Increased screening for CRC have been associated with a decreased incidence in the past two decades. Continued efforts are necessary to maintain this trend. Appropriate risk stratification of individuals and compliance with recommended screening strategies are important. Colonoscopy continues to play an important role in screening; however, several different screening options are available for average-risk individuals. This article reviews the current options open to physicians to adequately screen patients for CRC based on inherit risks.

CT colonography for synchronous colorectal lesions in patients with colorectal cancer: initial experience

AIM

To assess accuracy of CT colonography (CTC) in identifying synchronous lesions in patients with colorectal carcinoma.

METHODS

This study included 174 consecutive patients undergoing CTC as part of staging or primary investigation where a colorectal cancer was diagnosed between 2004 and 2007. Prone unenhanced and portal phase enhanced supine series with air or CO(2) distension were acquired using 4- or 16-slice CT (Toshiba) and read by 2D +/- 3D formats. Synchronous lesions were classified according to American College of Radiology's (ACR) polyp classification. Segmental gold standard was flexible sigmoidoscopy/colonoscopy within 1 year and/or histology of colonic resection supplemented by follow-up. Nine patients without gold standard were excluded. Sensitivity, specificity and accuracy were calculated on a per polyp, per patient and per segment basis and discrepancies analysed.

RESULTS

Direct comparable data were available for 764/990 colonic segments from 165 patients. Of 41 (C2-C4) synchronous lesions on "gold standard", 33 were correctly identified on virtual colonoscopy (VC), overall per polyp sensitivity was 80.5%, with detection rates of 20/24 C3 (83.3%) and 3/3 C4 (100%) with per patient and per segment specificity of 95.4% and 99.2%, respectively.

CONCLUSION

CTC is an accurate technique to assess for significant synchronous lesions in patients with colorectal cancer and is applicable for total pre-operative colonic visualisation.

Virtual colonoscopy vs conventional colonoscopy in patients at high risk of colorectal cancer--a prospective trial of 150 patients

OBJECTIVE

Virtual colonoscopy (VC)/CT colonography has advantages over the well-documented limitations of colonoscopy/barium enema. This prospective blinded investigative comparison trial aimed to evaluate the ability of VC to assess the large bowel, compared to conventional colonoscopy (CC), in patients at high risk of colorectal cancer (CRC).

METHOD

We studied 150 patients (73 males, mean age 60.9 years) at high risk of CRC. Following bowel preparation, VC was undertaken using colonic insufflation and 2D-spiral CT acquisition. Two radiologists reported the images and a consensual agreement reached. Direct comparison was made with CC (performed later the same day). Interobserver agreement was calculated using the Kappa method. Postal questionnaires sought patient preference.

RESULTS

Virtual colonoscopy visualized the caecum in all cases. Five (3.33%) VCs were classified as inadequate owing to poor distension/faecal residue. CC completion rate was 86%. Ultimately, 44 patients had normal findings, 44 had diverticular disease, 11 had inflammatory bowel disease, 18 had cancers, and 33 patients had 42 polyps. VC identified 19 cancers--a sensitivity and specificity of 100% and 99.2% respectively. For detecting polyps > 10 mm, VC had a sensitivity and specificity (per patient) of 91% and 99.2% respectively. VC identified four polyps proximal to stenosing carcinomas and extracolonic malignancies in nine patients (6%). No procedural complications occurred with either investigation. A Kappa score achieved for interobserver agreement was 0.777.

CONCLUSION

Virtual colonoscopy is an effective and safe method for evaluating the bowel and was the investigation of choice amongst patients surveyed. VC provided information additional to CC on both proximal and extracolonic pathology. VC may become the diagnostic procedure of choice for symptomatic patients at high risk of CRC, with CC being reserved for therapeutic intervention, or where a tissue diagnosis is required.

Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology

In the United States, colorectal cancer (CRC) is the third most common cancer diagnosed among men and women and the second leading cause of death from cancer. CRC largely can be prevented by the detection and removal of adenomatous polyps, and survival is significantly better when CRC is diagnosed while still localized. In 2006 to 2007, the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology came together to develop consensus guidelines for the detection of adenomatous polyps and CRC in asymptomatic average-risk adults. In this update of each organization's guidelines, screening tests are grouped into those that primarily detect cancer early and those that can detect cancer early and also can detect adenomatous polyps, thus providing a greater potential for prevention through polypectomy. When possible, clinicians should make patients aware of the full range of screening options, but at a minimum they should be prepared to offer patients a choice between a screening test that primarily is effective at early cancer detection and a screening test that is effective at both early cancer detection and cancer prevention through the detection and removal of polyps. It is the strong opinion of these 3 organizations that colon cancer prevention should be the primary goal of screening.

Comparison of radiologists and technologists in the performance of air-contrast barium enemas

OBJECTIVE

The purpose of this study was to determine whether the rate of polyp detection and the quality of air-contrast barium enema (ACBE) procedures performed by technologists differ from those performed by radiologists.

CONCLUSION

Our results showed that well-trained certified technologists can perform ACBE similar in overall quality and accuracy to ACBE performed by attending physicians and residents. Training technologists to perform ACBE may help to alleviate the radiology staffing shortage in the United States.

Intravasation of barium sulphate at barium enema examination

We report a case of venous intravasation of barium sulphate occurring during a routine barium enema examination for investigation of rectal bleeding. The patient suffered a cardiopulmonary arrest, but made a full recovery after organ support in intensive care. Review of radiographs from the examination showed intravasated barium in pelvic vessels. We review the literature on this rare, but serious, complication of barium enema examination and suggest measures by which intravasation can be prevented.

Perforation of the colon and rectum--a newly recognized complication of CT colonography

CT colonography (CTC) and conventional colonoscopy may have similar efficacy for detection of polyps > 6 mm. Perforation of the colon and rectum is a relatively rare, but potentially morbid complication of CTC, especially in symptomatic patients. Older age and underlying concomitant colon pathology increase the risk of perforation. This review describes the incidence, clinical features, and management of colon perforations at CTC, a study that was considered risk-free until recently.

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.

Minimal preparation CT for the diagnosis of suspected colorectal cancer in the frail and elderly patient

Colorectal cancer is a common malignancy with an increased incidence in the elderly population. Traditional methods of evaluating this disease have included double contrast barium enema and colonoscopy. Unfortunately, in the frail and elderly patient, these investigations can be difficult to perform and are often not tolerated. Minimal preparation computed tomography (MPCT) of the colon has been suggested as an alternative in this patient population. In this technique, no bowel preparation is used apart from the administration of oral contrast medium. The patient is imaged only in the supine position, without per rectal insufflation of gas or barium. This article reviews the experience to date of MPCT in detecting colonic tumours, and compares its efficacy to the traditional methods. A meta-analysis of the studies allowed estimation of the pooled sensitivity of MPCT to be 83% (95% confidence interval: 76-89%), and pooled specificity to be 90% (95% CI: 85-94%). An added advantage of MPCT is the ability to identify extra-colonic pathology, and this aspect is also reviewed. In addition, the common radiological features and pitfalls in identifying colonic tumours by MPCT are discussed.

Colonic perforation at CT colonography: assessment of risk in a multicenter large cohort

PURPOSE

To assess retrospectively the incidence, clinical features, and treatment of colonic perforation at computed tomographic (CT) colonography in a large multicenter cohort.

MATERIALS AND METHODS

The study was performed in accordance with the institutional ethics committees' requirements of a retrospective review in each of the participating centers, and no informed consent was required. A review of all patients who underwent CT colonography between January 2001 and December 2004 in 11 medical centers representing more than 95% of studies performed in a single country was performed to determine the rate of colorectal perforation. Data about patient demographics and patient- and procedure-related risk were recorded. Information about the location of the perforation, its likely mechanism, and treatment was collected. Analysis included calculation of rates of colonic perforation and surgical treatment and of 95% confidence intervals.

RESULTS

A total of 11 870 CT colonographic studies were performed in 6837 (57.6%) men and 5033 (42.4%) women (mean age, 59.9 years; range, 38-90 years) with seven cases of colorectal perforation, yielding a risk rate of 0.059% (one of 1696 studies; 95% confidence interval: one of 974, 971 of 6537). The mean age of the patients with perforation was 77.8 years. Six (84%) of seven cases of perforation occurred in symptomatic patients at high risk for colorectal neoplasia, and one (16%) occurred in an asymptomatic average-risk patient. All studies were performed after insufflation of room air. Six (84%) cases of perforation occurred in patients in whom a rectal tube was inserted, and in five of them, a balloon was inflated. Five (71%) cases of perforation occurred in the sigmoid colon; and two (29%), in the rectum. Four (57%) patients (one in 2968 patients; 95% confidence interval: 1.5 in 10 000, 14.7 in 10 000) required surgical treatment. Possible factors that contributed to perforation were left inguinal hernia containing colon (n = 4), severe diverticulosis (n = 3), and obstructive carcinoma (n = 1).

CONCLUSION

Perforation of the colon and rectum is a rare complication of CT colonography. Older age and underlying concomitant colonic disease were present in patients with perforation.

Causes of errors in polyp detection at air-contrast barium enema examination

PURPOSE

To retrospectively determine the cause of errors in air-contrast barium enema (ACBE) examination for detection of polyps 6 mm or larger.

MATERIALS AND METHODS

The study had institutional review board approval. Informed consent was waived for this HIPAA-compliant study. ABCE findings in 41 subjects with 56 missed polyps were evaluated by two radiologists to determine if the cause of errors was perceptual or technical. A comparison was made between total number of polyps in the proximal and distal colon and those missed at each location (Fisher exact test). The 288 ACBE examinations were assessed on a scale of 0-4 (0, excellent; 4, very poor) for six colonic segments (paired t test).

RESULTS

Of 17 polyps 1 cm or larger not detected in 15 subjects, 11 (65%) were missed because of technical errors and six (35%) because of perceptual errors. Eight (72%) technical and four (67%) perceptual errors occurred proximal to the splenic flexure. One 3.5-cm cecal carcinoma was not diagnosed prospectively (perceptual error). Of 39 6-9-mm polyps not detected in 26 subjects, 35 (90%) were missed because of technical errors and four (10%) because of perceptual errors. Eighty percent of technical and 75% of perceptual errors were in the proximal colon. When the proportion of polyps in the proximal and distal colon was compared, 22 (63%) of 35 polyps in the distal colon and 15 (26%) of 58 in the proximal colon were detected (P = .0009). There were no detectable differences in the quality of studies in subjects whose polyps were detected and subjects whose polyps were missed (P > .05).

CONCLUSION

Technical errors were more common than perceptual errors. The majority of missed polyps were in the proximal colon. Detection rates of polypoid lesions might increase if the quality of ACBE examination can be improved, especially 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.

Analysis of air contrast barium enema, computed tomographic colonography, and colonoscopy: prospective comparison

BACKGROUND

The usefulness of currently available colon imaging tests, including air contrast barium enema (ACBE), computed tomographic colonography (CTC), and colonoscopy, to detect colon polyps and cancers is uncertain. We aimed to assess the sensitivity of these three imaging tests.

METHODS

Patients with faecal occult blood, haematochezia, iron-deficiency anaemia, or a family history of colon cancer underwent three separate colon-imaging studies--ACBE, followed 7-14 days later by CTC and colonoscopy on the same day. The primary outcome was detection of colonic polyps and cancers. Outcomes were assessed by building an aggregate view of the colon, taking into account results of all three tests.

FINDINGS

614 patients completed all three imaging tests. When analysed on a per-patient basis, for lesions 10 mm or larger in size (n=63), the sensitivity of ACBE was 48% (95% CI 35-61), CTC 59% (46-71, p=0.1083 for CTC vs ACBE), and colonoscopy 98% (91-100, p<0.0001 for colonoscopy vs CTC). For lesions 6-9 mm in size (n=116), sensitivity was 35% for ACBE (27-45), 51% for CTC (41-60, p=0.0080 for CTC vs ACBE), and 99% for colonoscopy (95-100, p<0.0001 for colonoscopy vs CTC). For lesions of 10 mm or larger in size, the specificity was greater for colonoscopy (0.996) than for either ACBE (0.90) or CTC (0.96) and declined for ACBE and CTC when smaller lesions were considered.

INTERPRETATION

Colonoscopy was more sensitive than other tests, as currently undertaken, for detection of colonic polyps and cancers. These data have important implications for diagnostic use of colon imaging tests.

Management of colorectal cancers

The management of colorectal cancers, published in a recent issue of Effective Health Care, is reviewed.

Barium enema "shoulder" sign: a useful predictor of pericolonic fat invasion in colorectal cancer

PURPOSE

We aimed to determine the presence of the "shoulder" sign in prediction of pericolonic fat invasion on double-contrast barium enema (DCBE) studies in colorectal cancer.

MATERIALS AND METHODS

Patients at our institution with apparent colorectal cancer were identified from a computer search of both radiological and surgical pathology records during a recent 30-month period. The presence of a shoulder sign was defined as a tumor margin having an abrupt transition from the intraluminal component to the adjacent normal mucosa, forming a shouldered edge on barium studies.

RESULTS

A total of 49 patients (53 lesions) for whom the DCBE studies and surgical pathology records were available for review were proven to have colorectal carcinomas. DCBE studies revealed that 45 patients with lesions (85%) presented with a "shoulder" sign. All of these lesions were correctly diagnosed as colorectal cancer. Of these, 89% had pericolonic fat invasion and 44% had regional lymph node metastases. Of lesions without a shoulder sign, 25% had pericolonic fat invasion and 25% had nodal metastases.

CONCLUSION

The presence of shoulder sign detected with barium enema can be a useful predictor of pericolonic fat invasion in colorectal cancer.

Use of multidetector-row CT colonography for detection of colorectal neoplasia in patients referred via the Department of Health "2-Week-wait" initiative

AIM

Patients referred under the Department of Health 2-week wait initiative with symptoms of colorectal cancer frequently undergo whole-colon examination. We investigated the use of computed tomography (CT) colonography as an alternative to colonoscopy in this scenario.

MATERIALS AND METHODS

Fifty-four consecutive patients, referred via the 2-week wait initiative and scheduled for colonoscopy, consented to undergo multidetector CT colonography immediately before endoscopy. The site and morphology of any polyp or cancer detected by CT was noted and comparison made with subsequent colonoscopy.

RESULTS

Colonoscopy detected polyps or cancer in 29 patients (53.7%). CT colonography prospectively detected 18 of 41 (44%) polyps of 1-5 mm, three of four (75%) polyps of 6-9 mm, four of four (100%) polyps 10 mm or larger, and five of six (83%) cancers. The missed cancer occurred early in the series and was a perceptive error. The overall sensitivity, specificity, positive predictive value and negative predictive value of CT colonography for cancer and polyps 10 mm or greater on a per patient basis were 90, 100, 100 and 98%, respectively. CT detected one renal cancer and one colonic cancer, initially missed due to incomplete colonoscopy.

CONCLUSION

CT colonography is a robust technique for investigation of symptomatic patients. The learning curve must be overcome for optimal performance.

The role of sigmoidoscopy and colonoscopy in the diagnosis and management of lower gastrointestinal disorders: endoscopic findings, therapy, and complications

Flexible sigmoidoscopy and colonoscopy have revolutionized the clinical management of colonic diseases. Colonoscopy is a highly sensitive and specific test. Colonic diseases often produce characteristic colonoscopic findings, as well as characteristic histologic findings, as identified in colonoscopic biopsy or polypectomy specimens. Colonoscopy is relatively safe, with a low incidence of serious complications, such as colonic perforation, hemorrhage, cardiopulmonary arrest, or sepsis. Colonoscopy is becoming more important clinically because of more widespread use of screening colonoscopy for colon cancer, application of therapeutic colonoscopy, and exciting new technical improvements.

Radiology of colorectal cancer

In the past 20 years, the radiology of colorectal cancer has evolved from the barium enema to advanced imaging modalities like phased array magnetic resonance imaging (MRI), virtual colonoscopy and positron emission tomography (PET). Nowadays, primary rectal cancers are preferably imaged with transrectal ultrasound or MRI, while barium enema is still the most often used technique for imaging of colonic cancers. Virtual colonoscopy is rapidly evolving and might considerably change the imaging of colorectal cancer in the near future. The use of virtual colonoscopy for screening purposes and imaging of the colon in occlusive cancer or incomplete colonoscopies is currently under evaluation. The main role of PET is in detecting tumour recurrences, both locally and distantly. Techniques to fuse cross-sectional anatomical (computer tomography (CT) and MRI) and functional (PET) images are being developed. Apart from diagnostic imaging, the radiologists has added image-guided minimally invasive treatments of colorectal liver metastases to their arsenal. The radio-frequency ablation technique is now widely available, and can be used during laparotomy or percutaneously in selected cases.