STUDY DESIGN: Pelvic incidence (PI) was measured in 3 dimensions from computed tomographic (CT) images of normal subjects using a computerized method. OBJECTIVE: To obtain the angle of PI from 3-dimensional (3D) images and analyze its distribution in a normal population. SUMMARY OF BACKGROUND DATA: The sagittal alignment of the pelvis is usually evaluated in 2-dimensional (2D) sagittal radiographs. The purpose of this study is to measure and analyze PI, which represents a key parameter of sagittal alignment, in 3D images. METHODS: A computerized method, based on image-processing techniques, was used to automatically determine the anatomical references required to measure PI, that is, the centers of the femoral heads in 3 dimensions and the center and inclination of the sacral end plate in 3 dimensions. Multiplanar image reformation was applied to obtain perfect sagittal views with all anatomical structures completely in line with the hip axis from which PI was calculated. RESULTS: PI was successfully obtained in CT images of 370 normal subjects (mean age: 41.5 years; range: 1-87 years). The mean PI (± standard deviation) was equal to 46.6° (±9.2°) for male subjects, 47.6° (±10.7°) for female subjects, and 47.1° (±10.0°) for both sexes. No statistically significant differences were obtained between the sexes, and statistically significant correlation was obtained between PI and age. CONCLUSION: In this study, the sagittal alignment of the pelvis was evaluated in terms of PI completely in 3 dimensions. The results show that computerized measurements of PI in 3 dimensions are less variable than manual measurements. The large span of PI values for normal subjects indicates that the natural variation of PI is relatively large.
STUDY DESIGN: Pelvic incidence (PI) was measured in 3 dimensions from computed tomographic (CT) images of normal subjects using a computerized method. OBJECTIVE: To obtain the angle of PI from 3-dimensional (3D) images and analyze its distribution in a normal population. SUMMARY OF BACKGROUND DATA: The sagittal alignment of the pelvis is usually evaluated in 2-dimensional (2D) sagittal radiographs. The purpose of this study is to measure and analyze PI, which represents a key parameter of sagittal alignment, in 3D images. METHODS: A computerized method, based on image-processing techniques, was used to automatically determine the anatomical references required to measure PI, that is, the centers of the femoral heads in 3 dimensions and the center and inclination of the sacral end plate in 3 dimensions. Multiplanar image reformation was applied to obtain perfect sagittal views with all anatomical structures completely in line with the hip axis from which PI was calculated. RESULTS: PI was successfully obtained in CT images of 370 normal subjects (mean age: 41.5 years; range: 1-87 years). The mean PI (± standard deviation) was equal to 46.6° (±9.2°) for male subjects, 47.6° (±10.7°) for female subjects, and 47.1° (±10.0°) for both sexes. No statistically significant differences were obtained between the sexes, and statistically significant correlation was obtained between PI and age. CONCLUSION: In this study, the sagittal alignment of the pelvis was evaluated in terms of PI completely in 3 dimensions. The results show that computerized measurements of PI in 3 dimensions are less variable than manual measurements. The large span of PI values for normal subjects indicates that the natural variation of PI is relatively large.
Authors: Rob C Brink; Ludvig Vavruch; Tom P C Schlösser; Kasim Abul-Kasim; Acke Ohlin; Hans Tropp; René M Castelein; Tomaž Vrtovec Journal: Eur Spine J Date: 2018-08-20 Impact factor: 3.134
Authors: Tom P C Schlösser; Michiel M A Janssen; Tomaž Vrtovec; Franjo Pernuš; F Cumhur Oner; Max A Viergever; Koen L Vincken; René M Castelein Journal: Eur Spine J Date: 2014-05-17 Impact factor: 3.134
Authors: Thorsten Jentzsch; James Geiger; Samy Bouaicha; Ksenija Slankamenac; Thi Dan Linh Nguyen-Kim; Clément M L Werner Journal: BMC Med Imaging Date: 2013-11-05 Impact factor: 1.930