A single picture element in a computed tomography (CT) image is called what?

In computed tomography (CT) imaging, the term that accurately describes a single picture element is "voxel." A voxel, short for "volume element," refers to a three-dimensional unit that represents a value in a three-dimensional space. In contrast, a pixel is a two-dimensional element found in flat images, such as those generated by standard imaging techniques like radiography or ultrasound.

The distinction between a voxel and a pixel is crucial in understanding CT imaging, as CT scans provide volumetric data, allowing for the reconstruction of cross-sectional images. Each voxel in a CT image corresponds to a specific point in three-dimensional space and contains information about the density and composition of the tissues being scanned. This three-dimensional element is what allows CT to depict the internal structures of the body in more detail compared to traditional two-dimensional imaging modalities.

Understanding that a single image in CT is composed of multiple voxels helps in grasping the fundamental difference between CT imaging and other imaging techniques, which typically deal with two-dimensional representations of the data.