Application of anthropological aging methods to three-dimensional reconstructions of clinical CT scans of the adult pelvis

Abstract

Age estimation is a critical component of the biological profile in forensic anthropology. Features on the pelvis exhibiting morphological changes with age have been studied and include the pubic symphysis (e.g. Brooks and Suchey, 1990), the auricular surface of the ilium (e.g. Lovejoy et al., 1985 and Osborne et al., 2004), and the acetabulum (e.g. Rouge-Maillart et al., 2004 and Rissech et al., 2006). Access to the bony pelvis is not always accessible in the case of fleshed individuals or living, undocumented individuals. In recent years, three-dimensional computed-tomography (CT) technology has been developed to visualize the skeleton digitally. These digital images can be analyzed by anthropologists to establish the biological profile. Pelvic aging studies have been performed on CT scans of dry bones (Barrier et al., 2009; Ferrant et al., 2009; Telmon et al., 2005; and Pasquier et al., 1999), and rib aging studies have been performed on living individuals (Moskovitch et al., 20 I 0). The aim of this study is to test the applicability of 3D-CT skeletal aging to pelvic CT scans of live individuals. Forty-four patient CT scans from the Boston Medical Center were analyzed retrospectively for age at the time of the scan. Three-dimensional images were created using the volume-rendering capabilities of OsiriX software (Pixmeo, Geneva, Switzerland) and the images were analyzed for skeletal age using criteria for the pubic symphysis, auricular surface ofthe ilium, and acetabulum. Tests for intra-observer reliability were performed with pubic symphyseal aging. Pubic symphyseal age estimates captured the true age of the subject 79.5 percent of the time, and intra-observer agreement was high (Krippendorff's alpha coefficient of 0.65). Due to image quality, the auricular surface could only be analyzed in three cases, but resulted in age estimates that captured the true subject age each time. Acetabular age estimation proved the weakest of the three techniques; however, this could be due to the questionable applicability of acetabular aging standards outside of Western Europe in addition to limitations of the volume-rendering software. Ultimately, OsiriX proved to be an effective and efficient tool for creating three-dimensional images of the pelvis that could be analyzed accurately for skeletal age estimation.