Which factor is NOT typically associated with helical scans?

The factor that is not typically associated with helical scans is that they are precisely axial. Helical scanning, also known as spiral scanning, involves the movement of the CT scanner's x-ray tube in a continuous spiral motion as the patient is moved through the scanning area. This method allows for the collection of data along a helical path rather than in discrete axial slices.

In contrast to axial scanning, where images are taken slice by slice, helical scanning allows for more efficient image acquisition and reconstruction. This technique is known for creating smooth images and accommodating faster scanning times, as it can capture larger volumes of data in a single rotation compared to traditional axial methods. However, while helical scans are efficient and effective, they can potentially generate motion artifacts due to their continuous movement, especially if the patient moves during the scan.

Thus, stating that helical scans are "precisely axial" is misleading, as their defining characteristic is their helical nature, which sets them apart from axial scans.