Diagnostic paleoradiology of mummified tissue: interpretation and pitfalls.

D ead human and animal tissue can, because of natural conditions or artificial attempts, escape postmortem decay partially or even completely. This process called " mummification " derives linguistically from the Persian word mum or mom, which means beeswax. 1 In order to conduct an accurate radiologic diagnosis of the anatomical and pathologic changes in mummies, and thereby advance research in this area, a thorough knowledge of the process of mummification itself is required. The purpose of this article is to review the role of diagnostic paleoradiology in mummy studies. Natural mummification may occur under contrasting climatic conditions: the alpine/arctic process of freeze-drying, which requires sufficient air flow to sublimate body water; preservation in northern European peat bogs, in which acids interfere with enzymatic soft-tissue decomposition; or the mummification that can happen in the hot and arid environment of deserts. Artificial mummification can be achieved by embalming a body, as seen in the funerary tradition of Ancient Egypt where a physically well-preserved body was essential to gain immortality. Surprisingly, this method has been described very rarely in historical times and is passed on to us de facto only by Herodotus of Halicarnassus (fifth century BC) and by Diodorus Siculus (first century BC). Essentially, it involved the complete or incomplete removal of the internal organs using diverse tools. 2 Desiccation of the body was obtained by using natron, 3,4 a blend of NaCl, Na 2 CO 3 , NaHCO 3 and NaP 2 SO 4. 5 The term " natron " was coined after the Wadi Natrun region in Egypt. The embalming substance was a still mostly unknown mixture of natron with various preserving and aromatic products. 6–12 Finally, the corpse was wrapped with bandages and kept within a coffin in a well-sealed tomb. Since antiquity, the presence of valuable burial goods, such as jewellery and religious objects, in Egyptian tombs has attracted many thieves. Mummies recovered in modern times usually bear several stigmata of these acts of vandalism caused by tomb looters. Burial artifacts have also been removed during archaeological excavations and the scientific unwrapping of mummies. Mysterious deaths of scientists have been linked with the " curse of the Pharaohs, " a romantic speculation without any strong scientific basis. 13 Postmortem alterations of soft tissues and bone caused by artificial mummification are numerous. Internal organs were either removed completely and kept in jars or were put back in the …