Table 5.

Common scanning pitfalls effecting subjective image quality⁴²

Common pitfallsa	Recommendations for error correction & quality assurance
FOV error	Radiographer training in defining appropriate FOV Periodic review of FOV guidelines
Motion	Radiographer training in appropriate patient coaching, observation, & image review
Incomplete inspiration	Radiographer training in appropriate patient coaching & observation Rehearsal of inspiration and monitoring of full inspiration for breath-holding
Scan length error Over-scanning > 3 cm below the lungs Incomplete coverage of the lungs	Radiographer training on minimizing abdominal scanning including use of maximum inspiration for topogram and spiral images and use of lateral topogram Complete preliminary review of all images to ensure full coverage before patient leaves the scanner as part of examination completion checklist Periodic review of scan length guidelines
Artefacts obscuring anatomy Streak Ring Beam-hardening Excessive noise	Review scanner technology limitations and adjust acquisition parameters and/or conduct dedicated troubleshooting and maintenance procedures For patients with metal implants, such as orthopedic shoulder joint replacements, careful positioning is of benefit to minimize artefact

FOV, field of view.

^aFor CTLCS, FOV should be <3 cm beyond outer rib margins. No degradation of the study due to respiratory or trunk motion, and pulsation artefact should be minimized. Sufficient inspiration resulting in no more than minimal dependent atelectasis. A complete CTLCS examination includes the entire cephalocaudal length of lungs with no missing images, lung anatomy or gaps between sections. The number of CT sections below the most caudal lung containing image should be minimized. Anatomic feature should not be obscured by image artefacts (e.g. streak, ring or beam-hardening artefact).