Increasing compression reduces:

Increasing compression in ultrasound imaging refers to the process of reducing the dynamic range of the image data. Dynamic range is the measure of the range of amplitudes (or signal strengths) that a system can accurately capture and display. When compression is applied, the system essentially narrows the range of the amplitude values, allowing for easier visualization of certain features but potentially sacrificing the ability to see subtle differences in signal strength across the entire range.

By reducing dynamic range, the contrast between different tissue types may be diminished, because similar signal strengths will be represented in a narrower grayscale. This can result in a loss of detail in areas of the image where changes in intensity are small. Thus, increasing compression directly leads to a reduction in dynamic range, making this choice the correct answer.

In this context, understanding how compression affects the various aspects of imaging is crucial. While some might consider how spatial resolution might be impacted by compression, the primary effect is specifically on dynamic range, which is the key factor here.