CAMRT Radiography Practice Exam

In a CT scan, what does an increase in slicing thickness affect?

1. Spatial resolution

2. Contrast detail

3. Radiation dose

4. Image noise

The correct answer is: Spatial resolution

An increase in slicing thickness in a CT scan predominantly affects spatial resolution. Spatial resolution refers to the ability of the imaging system to differentiate between two closely spaced objects. When the slice thickness is increased, the amount of tissue included in each slice also increases. This can cause a blurring effect because details within the slice can overlap, leading to a loss of clarity in distinguishing fine anatomical structures. In imaging terms, thinner slices allow for better delineation of structures, meaning that as slicing thickness increases, the capacity to resolve spatial detail diminishes. This principle is crucial in diagnostic imaging where identifying small lesions or complex anatomy is necessary. While other factors like contrast detail, radiation dose, and image noise can be influenced by the choice of slice thickness, they do not primarily correlate as directly to changes in spatial resolution. For instance, an increase in slice thickness can sometimes increase image noise, but this is not as significant as its impact on spatial resolution. Hence, the choice that directly relates to the core principle of imaging resolution is spatial resolution.