Which axis position has changed when evaluating a series of coronal images?

When evaluating a series of coronal images in computed tomography, the Y-axis position is the one that is primarily altered. Coronal images are oriented in a plane that divides the body into anterior (front) and posterior (back) sections, and this orientation is associated with changes along the Y-axis.

In the context of CT imaging, the axes are typically defined as follows: the X-axis runs left to right, the Y-axis runs anterior to posterior, and the Z-axis runs superior to inferior. Therefore, when moving through a series of coronal images, you are effectively navigating through the Y-axis, capturing slices that vary in depth from the anterior to the posterior aspects of the anatomy.

This focus on the Y-axis is what distinguishes coronal imaging from other orientations, such as axial (which primarily affects the Z-axis) or sagittal (which primarily affects the X-axis). Thus, recognizing that coronal images represent changes along the Y-axis confirms why this is the correct answer.