How do Hounsfield units help in CT imaging?

Hounsfield units (HUs) play a crucial role in computed tomography (CT) imaging by providing a standardized scale for tissue characterization. This scale allows for the quantification of tissue density, facilitating the differentiation of various types of tissues based on their attenuation of X-rays. The Hounsfield scale is centered around the attenuation characteristics of water, which is assigned a value of zero. Air has a value of about -1000 HUs, and dense materials like bone can have values exceeding +1000 HUs.

By utilizing this scale, radiologists and medical professionals can analyze and interpret CT images more effectively. Distinct types of tissues—such as fat, muscle, and fluids—exhibit different Hounsfield unit values, enabling differential diagnosis and assessment of pathological conditions. This ability to characterize tissues is essential for evaluating tumors, cysts, and other anatomical structures, as it aids in determining their nature, composition, and potential treatment strategies.