Using a clinical scanning device, researchers in Switzerland have successfully captured CT images of the 17,000-year-old tusk of a woolly mammoth (Mammuthus primigenius).
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. Image credit: Eppenberger et al., doi: 10.1148/radiol.220265.
The woolly mammoth is an extinct mammal species that belongs to the order Proboscidea.
It inhabited large areas of the northern hemisphere, especially Eurasia, from approximately 700,00 to 4,000 years ago.
Woolly mammoths were covered in fur and had small ears and a small tail to abate frostbite.
They also had tusks that they used for scraping bark off trees, digging on the ground for food and fighting.
“The tusks of proboscideans allow determination of individual age and identification of specific life-altering occurrences based on annual growth-increment analysis,” said Dr. Tilo Niemann from the Department of Radiology at Kantonsspital Baden and colleagues.
The 17,000-year-old tusk of a 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. Image credit: Eppenberger et al., doi: 10.1148/radiol.220265.
In their research, the authors examined a large and well-preserved tusk of a woolly mammoth from central Switzerland.
The tusk had a total length of 2.06 m (6.8 feet), a diameter of 16 cm (6.3 inches), and a total object diameter of 80 cm (31.5 inches).
“Tusks mostly consist of two types of material: cementum, a bonelike substance, and dentin, which lies beneath the cementum and accounts for the majority of the tusk’s mass,” the researchers said.
“Mammoth tusks are internally structured by annual increments of dentin apposition which, when viewed in longitudinal section (as opposed to cross-section), resemble cone-shaped cups stacked on top of one another.”
Using a clinical CT unit featuring an improved design with an 82-cm- (32.3-inch) wide bore, they were able to capture a clear image of the entire tusk’s interior.
“It was fascinating to see the internal structure of the mammoth tusk,” Dr. Niemann said.
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.
Because the tusk tip is missing, the estimate obtained is slightly below the actual age.
“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,” the scientists said.
The results appear in the journal Radiology.
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Patrick Eppenberger et al. CT-based Age Estimation of a Mammoth Tusk. Radiology, published online August 9, 2022; doi: 10.1148/radiol.220265
Source link: https://www.sci.news/paleontology/woolly-mammoth-tusk-ct-scans-11082.html
