Strictures of the sigmoid colon: barium enema evaluation

Colorectal cancer mimics: a review of the usual suspects with pathology correlation

Colorectal cancer is the third most commonly diagnosed cancer in men and second most commonly diagnosed cancer in women worldwide. Initial diagnosis of colorectal malignancy is generally made on colonoscopy, sigmoidoscopy or digital rectal examination; however, with increased use of CT as primary investigation in patients with lower gastrointestinal symptoms, the diagnosis of colon cancer is often first apparent to a radiologist prior to more invasive tests. CT can demonstrate a discrete soft-tissue mass that narrows the colonic lumen or focal nodular wall thickening/stricture and a variety of pericolonic changes. Pattern of wall thickening has been described as an aid to differential diagnosis; however, significant overlap remains between primary colonic tumor and non-colonic tumors or benign conditions. Imaging is non-specific, and appropriate clinical history, direct inspection, histological analysis, and sometimes discussion at MDT are essential for accurate diagnosis and treatment planning. In this article, we will review the imaging features of some of these benign and malignant mimics of colorectal cancer, with accompanying histology slides where appropriate.

Computertomographische Diagnostik der akuten linksseitigen Kolondivertikulitis und ihre Differenzialdiagnostik

PURPOSE

This review shows the diagnostic potential of computed tomography (CT) in the diagnosis and differential diagnosis of acute left-sided colonic diverticulitis.

METHODS

Using a single detector spiral CT, standard examination of the entire abdomen is performed after oral and rectal administration of diluted iodinated contrast medium with collimation of 8 mm, pitch of 1.5, and reconstruction increment of 8 mm before and after intravenous contrast injection. Intravenous administration of spasmolytic agents, various patient positions, and the thin-section technique with 3-5 mm slices are beneficial in difficult cases.

RESULTS

The differential diagnosis of acute left-sided colonic diverticulitis includes tumorous, inflammatory, and ischemic diseases of the colon as well as infarctions of epiploic appendages and the omentum majus. The knowledge of the various CT criteria of acute colonic diverticulitis and their differential diagnoses helps to establish a correct diagnosis in a wide majority of cases.

CONCLUSION

At present, CT is the diagnostic procedure of choice for assessing acute diverticulitis. Distinct knowledge of the CT features helps to differentiate the various entities accurately.

National audit of the sensitivity of double-contrast barium enema for colorectal carcinoma, using control charts

AIM

To audit the sensitivity of double-contrast barium enema (DCBE) for colorectal carcinoma, as currently practised in UK departments of radiology.

METHODS

As part of its programme of national audits, the Royal College of Radiologists Clinical Radiology Audit Sub-Committee undertook a retrospective audit of the sensitivity of DCBE for colorectal carcinoma during 2002. The following targets were set: demonstration of a lesion > or =95%; correct identification as a carcinoma > or =90%.

RESULTS

Across the UK, 131 departments took part in the audit, involving 5454 examinations. The mean demonstration rate was 92.9% and the diagnosis rate was 85.9%, slightly below the targets set. The equivocal rate (lesion demonstrated, but not defined as malignant) was 6.9%, the perception failure rate was 2.8% and the technical failure rate was 4.4%. Control-chart methodology was used to analyze the data and to identify any departments whose performance was consistent with special-cause variation.

CONCLUSION

When compared with the diagnosis rate (84.6%) and demonstration rate (92.7%) reported in the Wessex Audit 1995, [Thomas RD, Fairhurst JJ, Frost RA. Wessex regional audit: barium enema in colo-rectal carcinoma. Clin Radiol 1995;50:647-50.] a similar level of performance was observed in the NHS today, implying that the basic process for undertaking and reporting DCBE has remained relatively unchanged over the last few years. Improvement in the future will require fundamental changes to the process of reporting DCBE, in order to minimize the perception failure rate and accurately to describe lesions, so reducing the equivocal rate. Control-chart methodology has a useful role in identifying strategies to deliver continual improvement.