"Modeling ancient Egyptian embalming": radiological assessment of experimentally mummified human tissue by CT and MRI.

Objective: To assess changes in different tissues during the process of artificial mummification by natron using computed tomography (CT) and magnetic resonance imaging (MRI), and to translate the results to image interpretation in paleoradiological studies of ancient mummies.
Materials and Methods: A human lower limb (LL) was amputated from a female donor 24 h post-mortem and mummified by artificial natron (54 % NaCl, 16 % Na2SO4, 18 % Na2CO3 12 % NaHCO3) in ancient Egyptian style. The LL was kept in a fume hood at 16-25 °C and 30-75 % relative humidity. CT and MRI were performed at specific intervals with quantitative evaluation of Hounsfield units (HU) and signal intensities (SI).
Results: Evaluated tissues showed different HU and SI changes during the experimental mummification. All tissues revealed an overall but varying increase of HU in CT examinations. All tissues except for the compact bone revealed an overall but varying decrease of SI in the IR and T2-weighted sequences of the MRI. Typical findings included a distinct increase of HU in the cutis at the end of the study and a temporary increase of SI in the IR and T2-weighted sequences in all muscle groups.
Conclusions: Radiological findings showed a regular, controlled and effective dehydration by the applied natron without detectable putrefaction. Evaluated tissues revealed different radiological changes during the experiment, which altogether led to preservation of the tissues without radiologically identifiable destruction. The cutis revealed radiological signs of direct interaction with the natron in the form of covering and possibly permeation.