title: Sex determination of the pelvis using Fourier analysis of postmortem CT images.
abstract: BACKGROUND
  The Fourier transform (FT) is an image-processing tool that can be used to analyze space or linear systems. We used the FT to analyze the shape of the subpubic line (SL) and the right greater sciatic notch area line (GSNAL) of the pelvis to identify sexing in computed tomographic (CT) images.
  
  
  METHODS
  120 bodies (60 male, 60 female) were scanned by multislice CT before autopsy. SL and GSNAL images were reconstructed using an image workstation. The range of the SL is between the bottom ends of the bilateral acetabulum, and the range of the right GSNAL is from the posterior superior iliac spine to the ischial tuberosity. Coordinates (x, y) of the bone outline were extracted from CT images and calculated by fast FT. The Mann-Whitney U test comparing the amplitude of each frequency was used to determine significant differences between the two populations. Multiple regression analyses were performed to find statistically significant amplitudes of each frequency. We verified the accuracy of prediction of the regression equation, and a Cohen's kappa coefficient was measured.
  
  
  RESULTS
  Statistically significant differences of amplitude were found in the 2nd, 3rd, and 4th frequencies of the SL and the 1st, 3rd, and 4th frequencies of GSNAL. Adjusted R(2) using all amplitudes having a significant difference was 0.772. The accuracy was 0.983. Kappa coefficient was 0.983.
  
  
  CONCLUSIONS
  We could determine sexing from SL and GSNAL of the pelvis using FT with high accuracy. FT is a useful tool to analyze the curved shape of human bone.
authors.affiliation: Department of Forensic Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan. Electronic address: yoshie@forensic.med.tohoku.ac.jp.
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Hayashizaki
authors.affiliation: Department of Diagnostic Image Analysis, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Usui
authors.affiliation: Department of Diagnostic Image Analysis, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Hosokai
authors.affiliation: Department of Forensic Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Sakai
authors.affiliation: Department of Forensic Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Funayama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D018732:Forensic Anthropology; D005583:Fourier Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D010384:Pelvic Bones / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D012044:Regression Analysis; D054881:Sex Determination by Skeleton / Q000379:methods*; D055815:Young Adult
keywords: Computed tomography; Fourier analysis; Greater sciatic notch; Pelvis; Sex determination; Subpubic