Hounsfield Unit (HU)

Hounsfield Units (HU) are a measure used in medical imaging, specifically in computed tomography (CT) scans, to quantify the density of different tissues in the body. Each material has a specific HU value: water is defined as 0, air is negative (around -1000), and denser substances like bone have positive values (up to +1000 or more). These values help radiologists differentiate between types of tissues—such as fat, muscle, and tumors—making it easier to diagnose conditions and plan treatments. Essentially, HU provides a standardized way to interpret the density of materials within the scanned area.