Leaps in CT scanning technology reveal more about the Saint Louis Art Museum's Egyptian mummies
In a dark room on the third floor of the Saint Louis Art Museum, nearly a dozen grade school boys encircled a tour guide, who was dispensing facts about Egyptian mummies. But instead of crowding around three mummies lying nearby in glass cases, they stood in front of a recently added feature to the exhibit: a touchscreen that displays images of what the mummies look like inside.
Since 2014, the museum and the Washington University School of Medicine has been using CT scans to study Egyptian mummies. CT scans — or computerized tomography — help doctors diagnose conditions, such as pneumonia or aneurysms. But with the mummies, the museum is working with radiologists to understand how ancient Egyptians treated human remains.
As the tour guide showed the students one image after another, Lisa Çakmak, the museum’s curator of ancient art, listened. A boy pointed at an image of a mummy and asked if its head was cut off.
“It’s not cut off,” Çakmak said. “It’s just that his spine got all messed up at some point after he was mummified.”
Çakmak then walked over to one of the sarcophaguses in the room.
“If you look at this, it just looks like a box,” Çakmak said. “It just looks like a coffin. And what the CT scanning allows us to do is really reanimate the person.”
Çakmak and Wash U’s radiologists scanned three mummies, one woman and two men, who lived in different dynasties, spanning 1,000 years. The woman, Henut-Wedjebu, is the oldest, dating to 19th century B.C. It’s clear that Henut held a high status in society, judging from her six-foot-long wooden coffin, which has the face of a beautiful woman painted with striking gold and black colors. She was buried in a tomb with her husband and a couple servants.
“She was the mistress of an elite household. When we say mistress of the house, it’s like anyone who’s watched ‘Downton Abbey.’ It’s like Lady Cora is mistress of ‘Downton Abbey,’” Çakmak said.
CT scans use many combinations of X-rays to see through thick layers. Henut’s CT scans revealed much more than her X-rays, Çakmak said.
“She’s wearing this really elaborate beaded headdress, and so when those pictures showed up on the CT scan and there were all these white dots on her face, the doctors were like, ‘Lisa, come look at this; what do you think it is?’ And I was like, ‘Oh, my God, those are beads,” Çakmak said.
Physicians in the 18th and 19th centuries literally unwrapped mummies to learn about what was inside them.
But there’s no putting them back together, said Jonathan Elias, director of the Akhmim Mummy Studies Consortium in Harrisburg, Pennsylvania.
“No matter how many notes you take at a time, as you’re ‘unrolling a mummy,’ as it was called, it’s done. It’s gone,” Elias said. “You’re left with a pile of linen and other materials. And then basically a naked body.”
Researchers began to use CT scans to study mummies in the 1970s. But the technology has advanced in recent years, and anthropologists like Elias are learning more than ever. The first time Elias CT scanned a mummy, it was in 2001, using a scanner that could make four “slices,” or cross-sections of the body. Now, the most powerful can make several hundred slices.
“It’s like going from working with stone tools to the space age,” Elias said.
Wash U radiologist Michelle Miller-Thomas also noted major differences between a mummy’s 1989 and 2014 CT scans.
“You can see in the 1989 scan, which is printed on film, it’s very washed out, and you don’t see a lot of detail,” Miller-Thomas said. “But with the 2014 image, I can manipulate that data to enhance different aspects of the image.”
The observations Egyptologists and art historians have made from CT scans has challenged some long-held beliefs about how ancient Egyptians prepared dead bodies. For example, it’s often taught in history classes that Egyptians removed the brain by inserting a hook through the nose and breaking a bone between the nasal and brain cavities. But Henut-Wedjebu’s brain is still in her skull.
Miller-Thomas, who specializes in the brain, was surprised by how much of the brain had remained after three thousand years.
“I can see the veins that drain the blood away from the brain; I could find the arteries that supply the fresh
blood coming into the brain,” Miller-Thomas said. “I think it’s amazing that this just didn’t liquefy and fall apart and turn into something completely unrecognizable.”
Such observations raise questions about how consistently ancient Egyptians removed the brain. The evidence anthropologists have seen suggests it was sometimes taken out, Elias said, but it’s important to note that ancient Egyptians believed that the heart operated a person’s conscience, personality and thoughts.
The brain was seen like a compass, something that helped a person maintain balance. But ancient Egyptians did not consider it a valuable organ, which is clear from the way they handled it, Elias said.
“Once the brain was removed, it was removed in a way which damaged it. Which is every un-Egyptian,” he said. “If they cared about that organ, they would have not damaged it.”
Researchers have also been 3-D printing objects seen in the CT scans. Wash U researchers printed, for example, a scarab that was placed near the heart of a dead priest named Amen-Nestawy-Nakht. His coffin also contained another object that will be 3-D printed and sent to Elias for analysis.
“It may be a small statue,” Miller-Thomas said. “We’re not certain yet. It seems to have some importance since it has a textile wrapping, like a sack around it.”
Using a 3D printer to recreate objects also reveals things that don’t show up even in the most detailed CT scans, Elias said. He once scanned a child mummy that had been supported by a wooden board to keep the body stiff. When the board was 3-D printed, Elias saw magical symbols inscribed on it.
“The thickness of paint itself on top of the surface, a 3-D printer can pick that up even though you can’t quite see it in screen language,” Elias said.
As CT scanning technology continues to evolve, researchers expect to discover more about how ancient Egyptians mummified bodies. But the evidence so far demonstrates what sets ancient Egyptians apart from other cultures.
“The body had to be preserved,” Elias said. “If they were confronted by a troubled situation, for example, or in a time of war, it would be a horror for them to leave anybody behind.”
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