Magnetic resonance imaging performed on a hydrated mummy of medieval Korea

Abstract

Previous investigations have shown that magnetic resonance imaging (MRI) can be employed as an efficient non-invasive diagnostic tool in studies on Egyptian mummies. MRI, moreover, because it produces especially clear images of well-hydrated tissue, could be a particularly effective diagnostic option for mummies that still retain humidity within tissues or organs. Therefore, in the present study, we tested MRI on a 17th century mummy, one of the most perfectly preserved 'hydrated mummies' ever found in Korea, in order to determine the quality of images that could be obtained. We found that the diagnostic value of an MRI scan of the hydrated mummy was not inferior to that of a computed tomography scan. The T1- and T2-weighted magnetic resonance (MR) signals showed unique patterns not easily obtained by computed tomography, the resultant MR images revealing the organ specificities clearly. Overall, the quality of the MR images from the hydrated mummy was superb and the scientific value of MRI in the study of hydrated mummies should not be underestimated.

Fig. 1

Magnetic resonance imaging on the head of the hydrated mummy. T1- and T2-weighted magnetic resonance (MR) images proved not to be very inferior to the computed tomography (CT) image. Although the skull (sk) is clearly seen on the CT scan, the T1- and T2-weighted MR images showed very weak or no signals, respectively. Magnified MR images exhibited the structures very clearly. The dura mater (dm), brain (Br) and scalp (sc) showed high signal intensities. The skull showed weaker signals on both images, especially on the T1-weighted image. Note the mixed signal intensities for the brain, which might have been due to the retention of the cortex and medulla.

Fig. 2

Magnetic resonance (MR) images for (A and B) chest, (C) abdominal and (D) pelvic regions. Note that the radiodensities of bone are very high, whereas signals on the T1- and T2-weighted MR images (indicated by white arrows) were not so intense. The lung (indicated by blank arrow) could be seen much more clearly on the T1- than on the T2-weighted image. Whereas the signal intensities of each organ or structure on the T1-weighted image all differed, the T2-weighted image showed much more homogeneous intensities. The tracheal (asterisks) or costal (gray arrows) cartilages were much more clearly seen on the T1- than on the T2-weighted MR image. Ht, heart. In (C), the intestines (indicated by the dotted circle) were very clearly seen on the T1- and T2-weighted MR images. (D) The feces (indicated by asterisks) could be clearly seen on the T1-weighted MR image but not on the T2-weighted image. Whereas the radiopacity of the feces on the computed tomography (CT) image was not very different from those of the other structures in the pelvic cavity, the same materials on the T1-weighted image showed intense signals only in the feces. As pelvic structures such as intestinal walls (indicated by arrowheads) could all be observed on the CT, T1- and T2-weighted MR images, feces showed unique signals on the MR images.

Fig. 4

Magnetic resonance imaging sagittal view of vertebral column. (A) High signal intensities could be seen in the vertebral column. (B) Magnified image of the dotted circle area in (A). Spinal canal (SC), ligamentum flavum (LF), posterior longitudinal ligament (PLL), nucleus pulposus (NP), annulus fibrosus (AF) and cartilaginous end of vertebral body (CE) can be seen clearly in (A). Spinal stenosis due to diffuse disc bulging (indicated by yellow arrows) can be observed.

Fig. 3

Magnetic resonance imaging axial view of vertebral column. The figures in the second column are magnified images of those in the first column. After we changed the gray colors in the T1-weighted magnetic resonance image to red, and those in the T2-weighted image to green, the two figures were merged into a single plate (merged). The cartilaginous end of the vertebral body (CE) or annulus fibrosus (AF) was seen clearly on the T1-weighted image. Even though the same structures (CE and AF) were also seen on the T2-weighted image, a possible nucleus pulposus (NP) could be identified in that T2-weighted image. In the merged T1- and T2-weighted images, the difference could be much more clearly observed. Only the signals on the T2-weighted image could be seen in the space where the NP should have been positioned, as signaled by the green color there.