Automatic constructed MSP of 3D skull based on original-mirror alignment

Abstract

Objective The study was to set up a landmark-independent protocol to construct the median sagittal plane (MSP) of CT reconstructed skull based on principle of original-mirror alignment and related accuracy evaluation.Methods CT data of 30 volunteers were included in the study.Data processing was performed using Mimics 11.0,and the MSP of each skull was generated by both landmark independent protocol (test protocol) and traditional protocol (control protocol).Test protocol involved four steps.Firstly,three dimensional skull was reconstructed.Secondly,mirror skull was generated via any top-bottom direction plane.Thirdly,the mirror skull was aligned on original skull automatically.Finally,the MSP was reconstructed according to the overlap section of mirror and original skull.Control protocol was practiced by one experienced doctor by manually selecting S,N and the most anterior point of foramen magnum.All the results were saved by frontal view screenshot,and the pictures were randomly numbered from 1 to 60.10 senior doctors subjectively graded the pictures by integer from 0 to 100.The scores were calculated by SPSS 17.0,and t test was performed to investigate the difference between test and control protocols.Results The average score of MSP generated by testing protocol was 84.4± 10.9,while that of control protocol was 66.2 ± 29.2.The former was significantly higher than the later (t=-6.255,P＜0.001).Conclusions MSP of 3D skull could be generated based on mirror original alignment principle,since the accuracy of landmark independent method is better than that of traditional method. Key words: Median sagittal plane; Landmark-independent construction; Interactive closet point algorithm