The external Haller index as a new, reliable, and accurate evaluation of pectus excavatum associating clinical assessment, 3-D surface scanning measurement, and MRI.

Pectus excavatum (PE) is the most common chest wall deformity. The traditional Haller index (HI), as measured using computed tomography (CT), guides surgical decision-making. Radiation-free magnetic resonance imaging (MRI) and less expensive alternatives, such as clinical thorax calipers or 3-D imaging, can measure the external Haller index (EHI).