Hounsfield unit average calculation (HUAC)

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Hounsfield unit average calculation (HUAC) is an imaging marker of sarcopenia, a key component of frailty . Psoas muscle assessment at L4 level is typically performed .

Sarcopenia has been associated with poor outcomes in trauma, oncology and surgical cases.

Hounsfield unit average calculation has been proposed as a novel "point-of-care" objective assessment of frailty. It can also be calculated using imaging alone as it is independent of patient height. Most patients undergoing surgery or treatment will undergo cross-sectional imaging, and the typical level for analysis is at L4. Segmentation software or a simple freestyle region of interest (ROI) provide area and average HU figures.

  • HUAC
    • (right area x density) + (left area x density) / total area

Levels to determine sarcopenia varies between publications (26 - 38 ) but is taken as the lowest quartile of values for your population, adjusted for gender.

See also