Indication

For screening studies, the CT colonography report should indicate whether there is a potential familial risk and should refer to any prior examinations. In symptomatic patients, documentation should include details of the nature and duration of symptoms and their onset. For follow-up examinations, relevant details from the patient′s medical history should be briefly given. Other important pieces of information such as an incomplete colonoscopy or refusal to undergo colonoscopy in the past should also be included in this section of the report.

Technical Description

As with any radiological examination, the CT colonography report should include a description of the examination technique. The bowel preparation and fecal tagging procedures, the method used for colonic distension (CO₂ or air), the scanning positions, and the dose–length product should all be included. If intravenous spasmolytics or contrast media have been administered, this should also be documented. Any use of CAD software should be mentioned as well.

Findings

Statement on quality and completeness of the examination. The quality and completeness of the examination are of key importance and should be mentioned at the top of the report. The evaluating radiologist should describe the quality of bowel preparation and fecal tagging and the presence of any stool or fluid residues. Any segments of the colon that could not be distended in both patient positions should be noted as well. The report should clearly document which segments were visualized and could be readily evaluated and which could not. The presence of large amounts of residual stool can severely restrict proper evaluation. Under such conditions, small and medium-sized polyps may not be detected. Any other factors limiting the accurate examination of certain colonic segments, such as beam-hardening artifacts—for instance, in patients with metal implants (hip prostheses, etc.)—should also be mentioned.

Colonic findings. In this section, both normal and pathological findings in the colon are reported. Ideally, the description includes the position and length of the colon. Variations in the length of the colon—for example, elongated colon—and positional anomalies (malrotation) should be noted. Morphological abnormalities of the bowel wall should be described next. The description of morphology includes the contours of the intestinal wall, the degree of haustration, the wall thickness, and enhancement in case of intravenous contrast administration.

Intracolonic abnormalities are documented according to the following criteria: lesion type, size, morphology, structure, and precise location.

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  First the lesion type is defined (e.g., polyp or mass). A colonic mass is defined as any lesion that is greater than 3 cm in its largest dimension.

  
  
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  The polyp diameter is the greatest diameter measured in the plane that best displays this dimension (for sessile polyps, this is often measured through the polyp base; for pedunculated polyps, it is measured along the head, excluding the stalk). For two-dimensional measurements, wide window settings should be used. Small or diminutive lesions are defined as lesions measuring up to 5 mm, medium-sized lesions are those measuring 6–9 mm, and large polyps are those measuring 10 mm or more.

  
  
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  With respect to morphology, polypoid lesions are described as sessile, pedunculated, or flat. A sessile lesion is one that is attached to the mucosa with a broad base. A pedunculated lesion has a polyp head which is connected to the mucosa by a stalk. Flat lesions are lesions that are not elevated more than 3 mm above the level of the mucosa. The morphology of a colonic mass is described as carpet-like, polypoid, saddle-shaped, semicircular, or circumferential.

  
  
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  The surface characteristics of the lesion should also be described. Lesions may be characterized as smooth, lobulated, or ulcerated.

  
  
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  Next, the 2D structure of the lesion is described (soft-tissue or fat attenuation, homogeneous/inhomogeneous), as is any contrast enhancement.

  
  
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  With regard to the location, the site of the lesion is described in terms of the six segments of the colon (rectum, sigmoid colon, descending colon, transverse colon, ascending colon, and cecum). The proximity of the lesion to a semilunar fold or to the anterior or posterior wall of the colon as well as the relationship to morphological landmarks should also be described.

  
  
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  Any associated extracolonic changes such as adjacent fat stranding or lymphadenopathy should be mentioned in this part of the report.

Extracolonic structures. In the second part of the report, extracolonic abdominal structures and the basal segments of the lung which are visible on CT colonography are also evaluated, noting the limitations if a noncontrast and/or low-dose technique was used.