Application of the Iscan Method to Two‐ and Three‐Dimensional Imaging of the Sternal End of the Right Fourth Rib*

Abstract

Age determination is a major field of interest in physical and forensic anthropology. Among the different methods based on macroscopic skeletal study, the Iscan method, which analyzes the sternal end of the right fourth rib, is one of the most reliable. We applied the Iscan method to two- and three-dimensional multislice computed tomography (MSCT) reconstructions of the sternal end of the right fourth rib on 39 ribs. The intra-observer variability on MSCT reconstructions was good (gamma coefficient equal to 0.86; value of the Krippendorff's alpha reliability equal to 0.79); inter-observer variability on MSCT reconstructions was also good (gamma coefficient ranging from 0.82 to 0.88; value of the Krippendorff's alpha reliability ranging from 0.78 to 0.86). We demonstrated excellent agreement between the results of analysis of bone samples and those of the two- and three-dimensional images, in particular regarding bone projections, morphology of the pit and of its rim. The accuracy of age estimation did not significantly differ between the Iscan method applied to dry bones and the same method applied to MSCT images. Determination of the Krippendorff's alpha reliability coefficient for the inter-error method confirmed the agreement between phase estimations obtained with the two methods (ranging from 0.55 to 0.71). The real civil age was comprised in 21 cases out of 36 for assessment performed on dry bones and in 23 cases out of 36 on MSCT reconstructions, which represented 58.3% and 63.9%, respectively. Use of MSCT reconstructions in forensic anthropology offers many advantages: no bone preparation, no damage to bone material, and the possibility of application to living individuals.

Virtual anthropology: useful radiological tools for age assessment in clinical forensic medicine and thanatology

“…Consequently, the radiologist who performs these investigations must be familiar with the techniques of physical and forensic anthropology. It is not possible to cite all the different methods transposed, but the most important and the most often used are the appearance of the right fourth rib according to the Iscan classification, and the auricular surface according to Lovejoy's classification [62,63]. The pubic symphysis using the Suchey-Brooks classification has also been studied, but specific MSCT measures have been determined and assessed (Fig.…”

Estimating Age at Death Based on Costal Cartilage Calcification

“…Calcification can be observed histologically during the first decade of life, and radiologically after the second decade (Rejtarova et al 2009). Many studies have used the fourth costal cartilage for estimating age (Iscan et al 1984a(Iscan et al , b, 1985Inoi 1997;Dedouit et al 2008;Fanton et al 2010;Verzeletti et al 2013;Cerezo-Roman and Hernandez Espinoza 2014;Haj Salem et al 2014), and some researchers have analyzed the first ribs (King 1939;Kampen et al 1995;Barchilon et al 1996;Kunos et al 1999), showing that calcification of the costal cartilage of the first rib is different to that of the other ribs (King 1939;Kampen et al 1995;Barchilon et al 1996;Kunos et al 1999). However, the costal cartilage of the first rib overlaps with the clavicle and soft tissue, and this makes it difficult to extract only the first costal cartilage from a CT image.…”

The epiphyseal scar: changing perceptions in relation to skeletal age estimation

“…This has allowed practitioners to undertake skeletal assessments, including skeletal age estimation, through virtual means rather than through dissection or maceration (Brough et al, 2012, Dedouit et al, 2008, Dedouit et al, 2007a, Dedouit et al, 2007b, Telmon et al, 2005.…”