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Computed tomographic (CT) colonography continues to evolve rapidly. Advances in scanning and display technologies, encouraging performance data, and increased utilization necessitate clarification and standardization of results reporting in CT colonography. There are several reasons for this. First and most important, standardized reporting can better assist patients and referring physicians in making management decisions on the basis of the results of CT colonography. The precedent of the mammography Breast Imaging Reporting and Data System, or BI-RADS, schema is a strong incentive to provide a similar structure for CT colonography. Second, as more examinations are performed, the likelihood increases that radiologists interpreting results of a CT colonography examination performed at one center will require comparison to examination results and reports generated at other sites. As has been seen with mammography, a common set of terms facilitates this kind of assessment (1). Third, as utilization of CT colonography increases, our colleagues in other medical specialties, the various third-party payers, and the general public will insist on larger-scale evaluations of examination performance, examination quality, patient outcome, and cost. Here again, a common approach to interpretation will assist us in meeting these demands. Finally, a common scheme for reporting facilitates structured reporting. The purpose of this communication is to facilitate clear and consistent communication of CT colonography results. The authors—an ad hoc group of investigators active in the area of CT colonography—have collaborated to develop a reporting scheme that is coupled to recommendations for follow-up. Our group, the Working Group on Virtual Colonoscopy, includes members of the American College of Radiology Colon Cancer Committee. On the basis of our collective experience and a review of the relevant literature, we present a practical guide to the interpretation of CT colonography results: the CT Colonography Reporting and Data System, or “C-RADS.” Future multidisciplinary collaboration and longitudinal data may lead to a refinement of the terms and concepts we present here; our effort is a starting point in which we attempt to address the needs of current practice. Adequate training and rigorous quality control of examination performance are essential elements for maximizing the potential of CT colonography; however, these related topics will not be discussed here. Instead, we will focus on the interpretation and follow-up of CT colonography results in three parts: first, a description of terms useful for reporting the size, morphologic features, and location of polyps and masses; second, a description of a classification scheme for colonic lesions and suggestions for follow-up; Published online 10.1148/radiol.2361041926 Radiology 2005; 236:3–9 1 From the Division of Abdominal Imaging and Intervention, Department of Radiology/ White 270, Massachusetts General Hospital, Boston, MA 02114 (M.E.Z.). The complete list of author affiliations is at the end of this article. Received November 12, 2004; accepted November 15. Address correspondence to M.E.Z. (e-mail: mzalis@partners.org).

To detect extravasation of contrast media during mechanical power injection at dynamic computed tomography, a 5 x 8-cm pliable adhesive patch was applied to the skin over the intravenous cannula and connected to the power injector with a cable to monitor electrical skin impedance. If the rate of change or the slope of impedance over time indicated an extravasation event, the power injector was set into a pause mode. In animal and human studies, monitoring with the device was successful. Extravasation of ionic contrast agents decreased impedance and that of nonionic agents increased impedance.

To retrospectively determine the diagnostic yield of double-contrast barium enema examinations performed for colorectal cancer screening of neoplasms 1 cm or larger or advanced neoplastic lesions of any size in average-risk adults older than 50 years.The Institutional Review Board at the affiliated Veterans Affairs Medical Center approved this HIPAA-compliant study protocol and did not require informed consent from patients. Computerized databases revealed 276 double-contrast barium enema examinations performed for colorectal cancer screening in average-risk adults older than 50 years. Radiographic and pathologic reports were reviewed to determine the number of patients who had polypoid lesions 1 cm or larger, polyps smaller than 1 cm, or advanced neoplastic lesions of any size. Forty-five (16.3%) of the 276 patients underwent follow-up sigmoidoscopy or colonoscopy. Medical, endoscopic, and pathologic records were reviewed and compared with radiographic findings.The results of double-contrast barium enema examination revealed 74 (26.8%) of 276 patients with 104 polypoid lesions in the colon, including 32 patients (11.6%) with 41 polypoid lesions 1 cm or larger, 15 patients (5.4%) with 19 polyps 6-9 mm, and 27 patients (9.8%) with 44 polyps 5 mm or smaller. Endoscopy was performed in 24 (75%) of 32 patients, the results of which confirmed 23 (72%) of 32 radiographically diagnosed lesions 1 cm or larger in 16 (67%) of 24 patients. In two of these individuals, the polyps were hyperplastic. The remaining 14 patients had a total of 21 neoplastic lesions 1 cm or larger, including 11 tubular adenomas, seven tubulovillous adenomas, one villous adenoma with marked dysplasia, and two cancers. The diagnostic yield of screening double-contrast barium enema examination was 5.1% (14 of 276 patients) for neoplastic lesions 1 cm or larger and 6.2% (17 of 276 patients) for advanced neoplastic lesions of any size.Double-contrast barium enema examinations performed in average-risk adults older than 50 years have a diagnostic yield of 5.1% for neoplastic lesions 1 cm or larger and 6.2% for advanced neoplastic lesions, regardless of size.

In the study by Kim et al, primary two-dimensional (2D) search with a three-dimensional (3D) problem-solving technique was compared with a 3D virtual dissection technique, with use of two independent reviewers. The authors observed no significant difference (P >.05) in sensitivity or specificity between the two techniques for the detection of polyps 6 mm or larger, whereas the median review time with virtual dissection was significantly (P

Patients with esophageal symptoms following drug ingestion underwent double-contrast upper gastrointestinal studies, and radiographic findings are described. Superficial esophageal ulceration and subtle mucosal abnormalities, which have not been seen on single-contrast radiographs, were confirmed on double-contrast radiographs. Erosions or ulcers usually occur in the region of the aortic arch and occasionally lower in the esophagus. Repeat esophagrams after withdrawal of the medication indicate resolution of the symptoms.

The authors prospectively evaluated 1,001 consecutive double-contrast barium enema examinations to determine the efficacy of the preliminary film. The scout films were evaluated for the presence of unsatisfactory amounts of residual feces and clinically significant extracolonic abnormalities. The contrast studies were independently evaluated in a double-blind manner for satisfactory colonic preparation as well as extracolonic abnormalities. The routine use of the scout film resulted in an increase in health care charges and departmental costs. In addition, there was no significant increase in the detection of extracolonic abnormalities. Our data suggest that routine use of scout films prior to contrast studies is unnecessary, although selective use in some clinical situations may be justified.

In 3,399 patients more than 40 years of age undergoing air-contrast enema examinations a prospective evaluation was done for the presence of colonic lymphoid follicles. In 3,315 patients there was no evidence of lymphoid follicles. Colonic neoplasms were diagnosed in 8.47% of these individuals. Eighty-four patients were found to have radiographically identifiable follicles. Fifty-eight of these 84 patients (69%) with lymphoid follicles had a synchronous (n = 19) or previous (n = 14) colonic neoplasm or a synchronous (n = 24) or previous (n = 1) colonic polyp. There were no consistent clinical or radiographic features that distinguished the patients with and without a neoplastic association. However, 90% of men with lymphoid follicles had associated neoplasms, whereas only 58% of women did. Because of the frequent association, detection of colonic lymphoid follicles in patients in this age group should lead to a vigorous search for subtle colonic neoplasms that may not be apparent because of technical limitations of the study.

The classic description of pseudomembranous colitis on barium enema studies is that of pancolitis with thickened haustral folds, a shaggy luminal contour, and/or mucosal plaques. However, the authors describe six patients with proved pseudomembranous colitis in whom barium studies (four double-contrast barium enema studies, one single-contrast barium enema study, and one peroral pneumocolon study) demonstrated rectosigmoid sparing with proximal colitis extending from the cecum to the sigmoid colon (three cases) or to the descending colon (three cases). In all six cases, endoscopy revealed a normal rectum or mild, nonspecific proctosigmoiditis without evidence of pseudomembranes in the rectosigmoid colon. Four patients had an atypical clinical presentation with bloody diarrhea (three cases) or minimal mucous diarrhea (one case). Thus, the diagnosis of pseudomembranous colitis may initially be suggested on barium studies in patients who have relative sparing of the rectosigmoid colon with characteristic findings more proximally in the colon.

The peroral pneumocolon examination is a method for obtaining a double-contrast image of the terminal ileum and right colon by insufflating air through a small catheter inserted into the rectum when orally ingested barium reaches the right colon. The examination is indicated if a detailed view of the ileocecal region is required, particularly when inflammatory bowel disease is suspected, when polyps are present in the right colon, or when patients are unable to tolerate barium enema studies.

To our knowledge, esophageal carcinoma that is metastatic to the gastric cardia has rarely been described in the radiologic literature. We examined seven patients who had a solitary metastasis in the gastric cardia that had spread from esophageal carcinoma. Five of the gastric lesions were synchronous with the primary lesion, and two developed after the primary tumor had been detected. Radiographically, the gastric lesion appeared as a submucosal mass in five patients and appeared to simulate a primary gastric carcinoma in the other two patients. The metastases had probably disseminated through the submucosal lymphatic system. Because the presence of a gastric metastasis may affect a patient's therapy, radiographic examination of the gastric fundus should be a routine part of the initial staging and/or follow-up evaluation of esophageal carcinoma.

The authors report 3 cases of lymphoma developing in patients with Crohn disease. Neither a cause-and-effect relationship nor a common etiology could be proven.