What Hounsfield unit corresponds to urine?

• A. 70
• B. 100 to 600
• C. 1
• D. -1000

Answer: (C)

The Hounsfield unit (HU) is a quantitative scale used in computed tomography (CT) imaging to measure radiodensity. Urine typically has a radiographic density that often falls within the range of Hounsfield units associated with soft tissues. While the approximate value for urine can vary based on concentration and composition, it generally falls within the range of about 1 to 10 Hounsfield units.

The choice indicating a value of 1 is representative of urine because it reflects the relatively low density of urine, which is much less dense than structures such as fat, muscle, or bone. This measurement helps differentiate various tissues and fluids in imaging studies, providing critical information for diagnosis and assessment in clinical settings.

In comparison, the other options provided reflect Hounsfield units that correspond to different types of materials, such as fat or air, which are not consistent with the properties of urine. Thus, the choice of 1 Hounsfield unit effectively represents the expected radiodensity of urine on a CT scan.