Validating 3D indexes in the non-surgical pectus excavatum patient

In recent years there has been an increased interest in three-dimensional (3D) imaging for the assessment of chest wall deformities. Some studies have proven a correlation between 3D and traditional cross-sectional images but only for patients who already had an indication for a computed tomography (CT) scan prior to surgery; mainly due to their severity. Our aim is to determine the accuracy and reliability of the measures obtained by a portable 3D scanner in a cohort of pectus excavatum (PE) patients with different severity grades, as well as in controls.

We conducted a study comparing radiological and optical indexes on magnetic resonance imaging (MRI) and 3D surface images. We used a hand-held 3D scanner to obtain the optical Haller Index (3DHI) and Correction Index (3DCI) and a limited MRI scan to obtain the traditional indexes. A statistical analysis was carried out to determine the correlation between optical and radiological measures, plus a subjective severity evaluation.

Twenty-eight patients and controls were enrolled in the study. In both the control and PE groups, there was a significant positive correlation between the indexes, especially for the CI. There were no differences in correlation regarding gender, age or severity. CI appears to better discriminate amongst the different severity groups and controls.

3D surface imaging is feasible and appropriate to use to assess PE, regardless of the severity or characteristics of the individual patient. Even with a small hand-held device, we can obtain accurate images and measures which are especially useful for the assessment of the nonsurgical pectus patient.