A blind accuracy assessment of computer-modeled forensic facial reconstruction using computed tomography data from live subjects.

A computer modeling system for facial reconstruction has been developed that employs a touch-based application to create anatomically accurate facial models focusing on skeletal detail. This article discusses the advantages and disadvantages of the system and illustrates its accuracy and reliability with a blind study using computed tomography (CT) data of living individuals. Three-dimensional models of the skulls of two white North American adults (one male, one female) were imported into the computer system. Facial reconstructions were produced by two practitioners following the Manchester method. Two posters were produced, each including a face pool of five surface model images and the facial reconstruction. The face pool related to the sex, age, and ethnic group of the target individual and included the surface model image of the target individual. Fifty-two volunteers were asked to choose the face from the face pool that most resembled each reconstruction. Both reconstructions received majority percentage hit rates that were at least 50% greater than any other face in the pool. The combined percentage hit rate was 50% above chance (70%). A quantitative comparison of the facial morphology between the facial reconstructions and the CT scan models of the subjects was carried out using Rapidform(™) 2004 PP2-RF4. The majority of the surfaces of the facial reconstructions showed less than 2.5 mm error and 90% of the male face and 75% of the female face showed less than 5 mm error. Many of the differences between the facial reconstructions and the facial scans were probably the result of positional effects caused during the CT scanning procedure, especially on the female subject who had a fatter face than the male subject. The areas of most facial reconstruction error were at the ears and nasal tip

Medical imaging and facial soft tissue thickness studies for forensic craniofacial approximation: a pilot study on modern Cretans

Forensic cases may require craniofacial approximations for unidentifiable victims. The accuracy of these approximations is improved by using population-specific average soft tissue depths. This study used CT scans from 64 Cretan adults (32 male and 32 female) to produce three-dimensional models of each individual’s cranium and skin surface. Using the models, the soft tissue depths were measured at 36 craniofacial landmarks; the means and standard deviations were calculated for the general Cretan population, and for male and female Cretans separately. Cretan facial soft tissue depths were then compared to those of French, Slovak, and Korean adults. 16 of the 36 landmarks exhibited sex differences among Cretans, with males having consistently thicker depths than females. The facial soft tissue depths of Cretan adults also presented significant differences when compared to other populations. Overall, the average soft tissue depths obtained represent the first database for the craniofacial approximation of Cretan (Greek) adults

Facial soft tissue thicknesses in Australian adult cadavers

Craniofacial identification methods heavily rely on the knowledge of average soft tissue depths. This study measured soft tissue thicknesses of an Australian cadaver sample (N533) using published needle puncture techniques at 13 anatomical locations. Data were compared and contrasted with other studies that used essentially identical samples and methods. Full descriptive statistics were calculated for measurements made in this study and means, medians, and modes were reported. Differences between mean values for males and females were found to be minimal (2.2mm or less) and considerable overlap was found between the groups. There were no statistically significant differences between the soft tissue depths of the sexes (P40.05). These findings indicate that differences between male and female soft tissue depths are of little practical significance for craniofacial identification and, therefore, data (means, standard deviations, and sample sizes) reported for Australians were pooled across the sexes and the studies. Although these new pooled means have increased statistical power, data distributions at some landmarks were skewed and thus emphasis is placed on median and modes reported for this study rather than upon the collapsed data means