[Application of cameral-type three-dimensional scan in assessment of funnel chest]

To evaluate the application of cameral-type three-dimensional (3D) scan in the assessment of funnel chest.

Eighty children with funnel chest were collected from the Children's Hospital, Zhejiang University School of Medicine during June 2016 and December 2017. All patients underwent routine CT scan. In the same selected mediastinal window, the lowest point of the depression to the front of the spine was the anteroposterior diameter (A1), and the maximum left to right diameter was B1 (which was perpendicular to A1). The ratio B1/A1 was calculated to get CT Haller index (CT-HI). In the same period, the chest wall scan was performed by EinScan-Pro 3D scanner, and the image was analyzed by GeoMedic image software. On the plane of the most concave point of the sternum, the distance from the lowest point of the skin to the back skin was the anteroposterior diameter (A2), the maximum plane diameter was measured on the same plane (B2), and the ratio B2/A2 was the 3D-Haller index (3D-HI). Pearson correlation analysis was used to analyze the consistency of the two measurements. Kappa test was used to analyze the consistency of surgical indication based on cutoff value of CT-HI and 3D-HI.

All children were able to cooperate with CT and 3D chest wall surface scan. The mean value of CT-HI was 3.82±0.96, and that of 3D-HI was 1.82±0.23. Pearson correlation analysis showed that the correlation coefficient between CT-HI and 3D-HI was 0.823 (P<0.01). When CT-HI > 3.2 and 3D-HI > 1.7 were set as cutoff values for indication of operation, the sensitivity and specificity of 3D-HI were 90.48% and 100.0%, respectively. 3D-HI was well consistent with CT-HI in surgical indication (Kappa=0.801).

s 3D scan can be used to assess the funnel chest in children, and 3D-HI>1.7 can be used as the cutoff value for surgical indication.