Post-processing a digital fluoroscopic image to a narrower window width will typically result in:

When post-processing a digital fluoroscopic image to a narrower window width, the result is a short scale contrast. The concept behind this involves the manipulation of the image's dynamic range through windowing techniques.

In digital imaging, window width refers to the range of pixel values that are displayed in the output image. A narrower window width means that only a small range of pixel values is represented, while the rest are either compressed or ignored. This focused range enhances the differences between the pixel values within that narrow band, leading to a more pronounced contrast in the image.

With short scale contrast, differences in gray levels become more distinct, allowing for better visualization of subtle differences in shades. This is particularly important in diagnostic imaging where small variations may indicate different anatomical structures or pathologies.

In contrast, a long scale contrast would mean a broader range of pixel values, resulting in a more gradual transition between shades and less distinct differences. The other options, such as no contrast scale change and variable scale contrast, do not accurately reflect the effect of narrowing the window width in digital imaging. The key takeaway is that narrowing the window width effectively enhances contrast by clustering pixel values and making the differences more noticeable.