What is the effect of increasing the slice thickness in a CT image?

Increasing the slice thickness in a CT image primarily reduces image noise while potentially sacrificing fine detail. When slice thickness is increased, more of the anatomy is included in each pixel, which averages out the signal and can lead to a reduction in noise. This can improve the overall clarity of the image, particularly in lower-contrast areas where noise might obscure important details.

However, while this reduction in noise can be beneficial, it comes at the cost of resolution concerning fine details. Thicker slices may cover more anatomical structures but can blur the distinctions between adjacent structures, making it harder to visualize small lesions or subtle anatomical features. Therefore, while noise reduction is a clear advantage of increasing slice thickness, the trade-off is a loss of the sharpness needed to resolve fine details, which is why this answer is considered correct.