Which statement is true about pixel characteristics in digital imaging?

The statement that each pixel is a picture element assigned a number is accurate because, in digital imaging, each pixel represents the smallest unit of graphic information and is assigned a specific number that corresponds to its intensity or color value. This numerical value allows the digital system to display varying shades of gray or color in an image, which is crucial for accurate imaging and analysis, especially in radiology.

Each pixel's value plays an integral role in how the image is formed visually and how details are interpreted when examining diagnostic images. Understanding that pixels are assigned numerical values helps to grasp concepts such as image resolution and contrast, which are fundamental in diagnostic imaging techniques.

The other options relate to characteristics of pixels but do not accurately represent the key attribute of pixels in digital imaging. For instance, while pixel values are typically discrete rather than continuous and pixels are reasonably standardized in size to maintain consistency across images, those characteristics may not be universally applicable, especially in systems with different resolutions or imaging modalities. The uniformity of pixel intensity representation can vary based on the imaging technique and the settings used, making B the most accurate recognition of pixel characteristics in digital imaging.