CT-based Age Estimation of a Mammoth Tusk.

HomeRadiologyVol. 305, No. 2 PreviousNext Reviews and CommentaryFree AccessImages in RadiologyCT-based Age Estimation of a Mammoth TuskPatrick Eppenberger, Renata Huber, Jochen Reinhard, Frank Rühli, Rahel A. Kubik-Huch, Tilo Niemann Patrick Eppenberger, Renata Huber, Jochen Reinhard, Frank Rühli, Rahel A. Kubik-Huch, Tilo Niemann Author AffiliationsFrom the Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland (P.E., F.R.); Office for the Preservation of Monuments and Archaeology, Kanton Zug, Zug, Switzerland (R.H., J.R.); and Department of Radiology, Kantonsspital Baden, Im Ergel 1, CH-5404 Baden, Switzerland (R.A.K.H., T.N.).Address correspondence to T.N. (email: [email protected]).Patrick EppenbergerRenata HuberJochen ReinhardFrank RühliRahel A. Kubik-HuchTilo Niemann Published Online:Aug 9 2022https://doi.org/10.1148/radiol.220265MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In The woolly mammoth (Mammuthus primigenius) is an extinct mammal species that belongs to order Proboscidea. It inhabited large areas of the Northern Hemisphere, especially Eurasia, from approximately 700–4 kyBP (1). The tusks of proboscideans allow determination of individual age and identification of specific life-altering occurrences based on annual growth-increment analysis (2).For the first time, a large and well-preserved tusk of a late-glacial mammoth from central Switzerland (3,4) was examined in toto with use of a clinical scanning device featuring an improved design with an 82-cm-wide bore (SOMATOM X.ceed, Siemens Healthineers) (Fig 1). The tusk had a total length of 206 cm, basal diameter of 16 cm, and total object diameter of 80 cm. The CT scans showed annual increments of dentin apposition from the central canal. A total of 32 cones were counted, resulting in an estimation of a minimum age of 32 years at the time of death (Fig 2). Because the tusk tip is missing, the estimate obtained is slightly below the actual age of the animal at death. Proboscidean tusks are continuously growing maxillary lateral incisors. In the tusk root, dentin is deposited on the surface of a conical pulp cavity, resulting in a distinct arrangement of growth increments associated with daily (third-order), weekly (second-order), and annual (first-order) periodicities; in this instance, the latter was evaluated for age determination (5). To our knowledge, this was the first successful scan of an intact, adult male mammoth tusk in toto with use of a clinical CT unit without multiple partial scans.Figure 1: Photograph of the positioning of the woolly mammoth tusk in the scanner. The tusk was fixed in a fiberglass frame to guarantee transport and table-movement stability. There was 1 cm of clearance within the gantry bore.Figure 1:Download as PowerPointOpen in Image Viewer Figure 2: Images in tusk of the woolly mammoth. (A) Volume-rendering reconstruction shows the dentin conal structure of a mammoth tusk for age determination. (B) Illustration of the dentin conal structure of a mammoth tusk. (C) Curved-planar reconstruction CT image centered in the tusk, with orange lines representing the level of perpendicular sections corresponding to images D–F. (D–F) Cross sections of CT images show concentric fissures in the dentin, with (E) mild artifact in the most peripheral scan field.Figure 2:Download as PowerPointOpen in Image Viewer Disclosures of conflicts of interest: P.E. No relevant relationships. R.H. No relevant relationships. J.R. No relevant relationships. F.R. No relevant relationships. R.A.K.H. Technology partnership between hospital and Siemens Healthineers. T.N. No relevant relationships.AcknowledgmentsAt Kantonsspital Baden, Switzerland, the CT scanner SOMATOM X.ceed was installed before general availability in the framework of the technology partnership with Siemens Healthineers. We thank the development team of Siemens Healthineers for their excellent cooperation. We thank Mallory Eckstut, PhD, from Edanz (https://www.edanz.com/ac) for editing a draft of this manuscript.References1. Chang D , Knapp M , Enk J , et al. The evolutionary and phylogeographic history of woolly mammoths: a comprehensive mitogenomic analysis. Sci Rep 2017;7(1):44585. Crossref, Medline, Google Scholar2. Grigoriev SE , Fisher DC , Obadă T , et al. A woolly mammoth (Mammuthus primigenius) carcass from Maly Lyakhovsky Island (New Siberian Islands, Russian Federation). Quat Int 2017;445:89–103. Crossref, Google Scholar3. Drucker D , Furtwängler A , Schüneman VJ , Reinhard J. Durchleuchtet und analysiert. Ein update zur genetik, isotopie und radiografie des «letzten Zuger Mammuts». Tugium 2018;34:123–131. Google Scholar4. Huber R , Reinhard J. Das letzte Zuger Mammut? Eine baugrube als fenster in die späte eiszeit. Tugium 2016;32:103–110. Google Scholar5. Fox DL. Growth increments in Gomphotherium tusks and implications for late Miocene climate change in North America. Palaeogeogr Palaeoclimatol Palaeoecol 2000;156(3-4):327–348. Crossref, Google ScholarArticle HistoryReceived: Feb 3 2022Revision requested: Feb 28 2022Revision received: Mar 28 2022Accepted: Apr 5 2022Published online: Aug 09 2022Published in print: Nov 2022 FiguresReferencesRelatedDetailsRecommended Articles Bone Metastases: State of the Art in Minimally Invasive Interventional OncologyRadioGraphics2021Volume: 41Issue: 5pp. 1475-1492Susceptibility-weighted Imaging: Technical Essentials and Clinical Neurologic ApplicationsRadiology2021Volume: 299Issue: 1pp. 3-26CT for Pre- and Postprocedural Evaluation of Transcatheter Mitral Valve ReplacementRadioGraphics2020Volume: 40Issue: 6pp. 1528-1553Improving Image Quality and Reducing Radiation Dose for Pediatric CT by Using Deep Learning ReconstructionRadiology2020Volume: 298Issue: 1pp. 180-188The Use and Pitfalls of Intracranial Vessel Wall Imaging: How We Do ItRadiology2017Volume: 286Issue: 1pp. 12-28See More RSNA Education Exhibits ACR CT Accreditation Testing and Routine Quality Control for Clinical Photon-Counting Detector CT: Practical Tips and TricksDigital Posters2022How Do Metal Artifacts in the Pelvis Influence on CT Colonography? 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