Pitfalls in Multi–Detector Row CT Colonography: A Systematic Approach

Abstract

Thin-section multi-detector row computed tomographic (CT) colonography is a powerful tool for the detection and classification of colonic lesions. However, each step in the process of a CT colonographic examination carries the potential for misdiagnosis. Suboptimal patient preparation, CT scanning protocol deficiencies, and perception and interpretation errors can lead to false-positive and false-negative findings, adversely affecting the diagnostic performance of CT colonography. These problems and pitfalls can be overcome with a variety of useful techniques and observations. A relatively clean, dry, and well-distended colon can be achieved with careful patient preparation, thereby avoiding the problem of residual stool and fluid. Knowledge of the morphologic and attenuation characteristics of common colonic lesions and artifacts can help identify bulbous haustral folds, impacted diverticula, an inverted appendiceal stump, or mobile polyps, any of which may pose problems for the radiologist. A combined two-dimensional and three-dimensional imaging approach is recommended for each colonic finding. A thorough knowledge of the various pitfalls and pseudolesions that may be encountered at CT colonography, along with use of dedicated problem-solving techniques, will help the radiologist differentiate between definite colonic lesions and pseudolesions.

CT Colonography (Virtual Colonoscopy): Technique, Indications and Performance

“…It is important to realize that although CTC is a powerful tool for colonic polyp and tumor detection, there are many pitfalls for misdiagnosis. These include: (1) technical errors: due to suboptimal patient preparation with a large amount of residual stool or fluid, under distension or spasm of the colon, respiratory and metallic artifacts, image noise; (2) pitfalls related to evaluation technique such as incorrect window settings, 3D threshold values; (3) pitfalls related to reading such as failure to detect lesions and misinterpretation of findings [57. ]…”

Diagnostic accuracy of translucency rendering to differentiate polyps from pseudopolyps at 3D endoluminal CT colonography: a feasibility study

“…Our data need to be confirmed in larger prospective studies. Second, our analysis did not include some well-recognised pitfalls at 3D endoluminal image analysis [22][23][24], such as impacted diverticula, submucosal lipoma or intraluminal mass effect from extrinsic extracolonic lesions. We believe that these findings, although previously described in the literature, represent uncommon causes of false-positive findings at 3D endoluminal image analysis.…”

Benign Diseases of the Colon and Rectum (incl. CT colonography)

“…This causes a polypoid filling defect on endoluminal 3D views, with a pathognomonic aspect on 2D views: the diverticular fecalith almost invariably presents as a round structure with a hyperdense ring and a hypodense center corresponding to an air occlusion [22]. It can protrude from the diverticulum into the colonic lumen.…”