When performing a CT scan or MRI, codes are selected based on the contrast used. Which of the following is NOT a criterion?

In the context of coding for imaging studies such as CT scans or MRIs, the selection of codes is closely tied to how the imaging procedures are performed, particularly concerning the use of contrast material. The criteria for coding typically include options for when the imaging is performed with contrast, without contrast, or using both approaches.

The option referring to inpatient status does not directly affect the use of contrast for coding purposes. This is because the determination of whether a code falls under "with contrast," "without contrast," or "with and without contrast" is based on the specifics of the imaging procedure itself, not the patient's inpatient or outpatient status.

In contrast, the other criteria focus on the actual methods used in the imaging process, which play a crucial role in determining the appropriate coding. Thus, this highlights why inpatient status is not considered a criterion when selecting codes for procedures involving contrast during CT or MRI scans.