Comparison of ultrashort echo time sequences for MRI of an ancient mummified human hand.

PURPOSE: To compare the three different short-echo time (TE) pulse sequences ultrashort echo time (UTE), point-wise encoding time reduction with radial acquisition (PETRA), and single point imaging (SPI) for MRI of ancient remains. METHODS: MRI of mummies is challenging due to the extremely low water content and the very short transverse relaxation times T2 *. To overcome the signal loss associated with the short T2 *, three pulse sequences with very short TEs were compared. MR images of an ancient mummified human hand were acquired at field strengths of 1.5 Tesla (T) and 3T using home-made solenoid Tx/Rx radiofrequency (RF) coils. RESULTS: In all MR images, tissues could be differentiated and anatomical structures such as bones and tendons were clearly identified. Skin with embalming resin was hyperintense in MRI, whereas it appeared iso-intense in computed tomography. PETRA has the highest signal to noise ratio. With UTE, short scan times and a homogeneous RF excitation can be achieved, and blurring is less pronounced than with PETRA. SPI shows no blurring artifacts; however, it requires long scan times. CONCLUSION: This work provided an initial analysis for the optimization of imaging protocols for paleoradiology studies with MRI, and, ultimately, for MRI of tissue with extremely short T2 *.

Scenes from the past: MR imaging versus CT of ancient Peruvian and Egyptian mummified tissues.

Ancient Egyptian and Peruvian mummies are extremely valuable historical remains, and noninvasive methods for their examination are desirable. The current standard of reference for radiologic imaging of mummies is computed tomography (CT), with tissue having a homogeneous appearance on all CT images. It was long believed that ancient mummified tissue could not be studied with magnetic resonance (MR) imaging because of the low water content in mummies. Recently, however, the usefulness of MR imaging in the evaluation of mummified tissue was demonstrated for the first time, with use of a special ultrashort echo time technique. The authors of the present study acquired and analyzed MR imaging and CT data from the left hands of two ancient Egyptian mummies and the head of a third Egyptian mummy (ca 1500-1100 bce), as well as data from an ancient Peruvian mummy (ca 1100 ce). CT was found to provide superior detail of the anatomic structures, mainly because of its higher spatial resolution. The signal intensity of mummified tissue varied greatly on MR images; thus, the quality of these images is not yet comparable to that of clinical MR images, and further research will be needed to determine the full capacity of MR imaging in this setting. Nevertheless, additional information may theoretically be obtained with MR imaging, which should be viewed as complementary to, rather than a replacement for, CT.

Radiological and histological findings in ancient salt mummies from the salt mine of Douzlakh, Iran.

Computed tomography studies and histological analyses were performed on the mummified remains found in the Chehrabad salt mine in northwestern Iran. The ancient salt mummies are dated to the Achaemenid (550-330 BC) and Sassanid (3rd-7th century AD) time period and died in mining incidents. The aim of the study was to describe the radiological and histological findings of several ancient Iranian salt mummies with special interest in pathological and postmortem changes. The mummified remains show multiple traumatic alterations, such as fractures and signs of massive compression. Histological analyses can clearly differentiate soft tissue, however the preservation status is variable. These Iranian salt mummies are a rare example of the ancient Iranian population. The soft tissue and organs are well preserved, however in different degrees due to the varying conditions.