CT colonography image interpretation requires simultaneous detection of colonic pathologic disease and recognition of pitfalls that can simulate or obscure real findings. Artifacts and pseudolesions are commonly encountered at CT colonography and far exceed the frequency of true colonic pathologic disease. They pose a real challenge to the interpreting radiologist, who must be knowledgeable about their many appearances. Some are intrinsic to either two-dimensional (2D) or three-dimensional (3D) CT colonography images and others are unavoidable on both. Nearly all artifacts are equally visualized on 2D and 3D images, whereas most pseudolesions are visualized solely on 3D images. Artifacts are often unavoidable at CT colonography and can degrade image quality on both 2D and 3D images, whereas pseudolesions almost always plague 3D images and can usually be rapidly disregarded, as they are unsubstantiated on corresponding 2D images. Mastery of interpretative skills and careful correlation of findings on 2D and 3D images allow the radiologist to unmask artifacts and pseudolesions and avoid diagnostic errors. Misinterpretation of a pseudolesion as colonic pathologic disease can lead to subsequent optical colonoscopy and unnecessary risk to the patient. Some artifacts and pseudolesions can be circumvented with optimal colonic cleansing, adequate fecal and fluid tagging, ideal colonic distention, and optimization of examination technique. The authors discuss the causes and appearances of artifacts and pseudolesions at CT colonography, provide an interpretative approach for their recognition, and review strategies to decrease or prevent them.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging