CT scan modes include both axial and helical scanning. The selection of axial or helical CT depends on the clinical task. In this video we describe the differences between axial and helical scanning and the different conditions that each scan type or scan mode is best for.
CT (Computed Tomography) scanning can be accomplished with multiple different scan modes which have different characteristics. Axial non-volumetric scanning is how CT began where one (or just a few) slices are acquired during each gantry rotation. Traditional helical scanning (some call spiral) has the advantage of being faster than non volumetric axial scanning and also uses data continuously for improved motion robustness. There are then different specialized versions of helical scanning from low pitch scanning for cardiac to high pitch helical scanning for fast volumetric acquisitions. For state of the art systems wide coverage volumetric axial scanning is also an option to cover an entire organ in one rotation. These acquisitions are particularly useful for repeated scanning such as in time resolved angiography or perfusion applications.
For a detailed comparison of the scan modes see our illustrated blog post:
howradiologyworks.com/14040-2/