What is the range for the CT number of blood?

The CT number, also known as Hounsfield Units (HU), is a scale used in computed tomography (CT) to quantify radiodensity. This scale ranges from negative values (representing less dense materials) to positive values (representing denser materials).

Blood typically has a CT number that falls into a range reflecting its composition and density. The correct answer indicates that the CT number for blood is between 20 to 80 Hounsfield Units. This range is primarily due to the presence of water and the protein content in plasma, which contribute to blood's overall density.

Understanding CT numbers is crucial for distinguishing various tissues and materials during imaging. The range for blood (20 to 80) takes into account that it is more dense than water (which has a CT number of 0) but less dense than many other bodily tissues. This helps in the assessment of various medical conditions where blood flow and presence are key factors.

In clinical practice, knowing the correct CT number range for blood allows healthcare professionals to interpret CT scans accurately and identify pathological conditions related to blood volume or density, thus enhancing diagnosis and treatment planning.