title: Aging adult skull remains through radiological density estimates: A comparison of different computed tomography systems and the use of computer simulations to judge the accuracy of results.
abstract: BACKGROUND
  The objective of this article was to explore age-at-death estimates in forensic medicine, which were methodically based on age-dependent, radiologically defined bone-density (HC) decay and which were investigated with a standard clinical computed tomography (CT) system. Such density decay was formerly discovered with a high-resolution flat-panel CT in the skulls of adult females. The development of a standard CT methodology for age estimations--with thousands of installations--would have the advantage of being applicable everywhere, whereas only few flat-panel prototype CT systems are in use worldwide.
  
  
  METHODS
  A Multi-Slice CT scanner (MSCT) was used to obtain 22,773 images from 173 European human skulls (89 male, 84 female), taken from a population of patients from the Department of Neuroradiology at the University Hospital Giessen and Marburg during 2010 and 2011. An automated image analysis was carried out to evaluate HC of all images. The age dependence of HC was studied by correlation analysis. The prediction accuracy of age-at-death estimates was calculated. Computer simulations were carried out to explore the influence of noise on the accuracy of age predictions.
  
  
  RESULTS
  Human skull HC values strongly scatter as a function of age for both sexes. Adult male skull bone-density remains constant during lifetime. Adult female HC decays during lifetime, as indicated by a correlation coefficient (CC) of -0.53. Prediction errors for age-at-death estimates for both of the used scanners are in the range of ±18 years at a 75% confidence interval (CI). Computer simulations indicate that this is the best that can be expected for such noisy data.
  
  
  CONCLUSIONS
  Our results indicate that HC-decay is indeed present in adult females and that it can be demonstrated both by standard and by high-resolution CT methods, applied to different subject groups of an identical population. The weak correlation between HC and age found by both CT methods only enables a method to estimate age-at-death with limited practical relevance since the errors of the estimates are large. Computer simulations clearly indicate that data with less noise and CCs in the order of -0.97 or less would be necessary to enable age-at-death estimates with an accuracy of ±5 years at a 75% CI.
authors.affiliation: Department of Neuroradiology, UKGM, Klinikstraße 33, D-35392 Gießen, Germany. martin.obert@radiol.med.uni-giessen.de
authors.forename: Martin
authors.initials: M
authors.lastname: Obert
authors.forename: Carolin
authors.initials: C
authors.lastname: Kubelt
authors.forename: Thomas
authors.initials: T
authors.lastname: Schaaf
authors.forename: Benjamin
authors.initials: B
authors.lastname: Dassinger
authors.forename: Astrid
authors.initials: A
authors.lastname: Grams
authors.forename: Elke R
authors.initials: ER
authors.lastname: Gizewski
authors.forename: Gabriele A
authors.initials: GA
authors.lastname: Krombach
authors.forename: Marcel A
authors.initials: MA
authors.lastname: Verhoff
mesh_terms: D000293:Adolescent; D000328:Adult; D000365:Age Determination by Skeleton / Q000379:methods*; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D005260:Female; D018732:Forensic Anthropology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D012727:Sex Characteristics; D012886:Skull / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D055815:Young Adult