The tumor starts at the back of the girl’s right eye. It extends down through the nasal cavity before engulfing the right side of the jaw, even enveloping some teeth. Such a massive tumor would surely have made eating difficult for the child, who died during the 15th century in what was likely present-day Peru. The girl was wrapped in textiles and a cord net and placed in a pit or an enclosed aboveground space. There the warm, dry air naturally mummified her body.

Six centuries later researchers have mapped out the tumor’s contours using high-tech medical imaging technology—computed tomography (CT) scans. With the images, they were also able to see the child’s poorly developed bones and teeth—evidence that she was malnourished. Today, such a tumor would be operable.

Studies such as this are important not only because they provide clues about how ancient people lived. They may also reveal new details about medical conditions that affect us now. For example, recent research on mummies from ancient Egypt and South America has found evidence of hardening of the arteries that could have led to heart attacks and strokes, although this is often considered to be a condition that occurs as a result of modern lifestyles.

Researchers today use a number of tools from physicians’ tool kits to examine the delicate soft tissue of mummies. DNA analysis, for example, can help reveal a mummy’s identity or help identify illnesses. Scientists have used DNA analysis to study ancient strains of tuberculosis, work that has helped them understand how the bacteria has evolved through the centuries. In addition, 3-D printing can be used to make mock versions of body parts like the pelvis or examine what may be trapped inside a mummy’s clenched fist without disturbing the body itself.

But the most important tool in a mummy specialist’s arsenal is the CT scan, because it helps scientists peer beneath mummies’ wraps. Researchers use CT scans to ferret out basic information like a mummy’s sex, which is not easy to discern hundreds of years after death. They also employ the scans to examine mummy skeletons, which helps them estimate a specimen’s age at death. “Medical imaging for us is without a doubt the most important development for mummy research in the last 20 years,” says Heather Gill-Frerking, director of science and education for Mummies of the World, the largest traveling exhibition of mummies and artifacts in the world. The exhibition, currently being shown at the Maryland Science Center in Baltimore, includes one of the oldest mummy infants ever discovered, a mummified lizard from the Sahara Desert and a cache of 18th-century mummies uncovered in a long-forgotten church crypt in Hungary.

These Hungarian mummies were preserved naturally through a combination of the cool, dry air continuously flowing through the crypt and the oil from the pine board used in their coffins. DNA analysis of lung tissue and CT scans of these mummies revealed that more than half of the 265 mummies had tuberculosis when they died.

But even with the help of precision CT scans, mummy detective work isn’t all that straightforward. “After death there are changes to the body. All the bits are there but they might not be as you expect them to be or where you expect them to be. Quite often you will see a series of organs in the abdomen and you have to figure out which is which,” says Gill-Frerking. “Things move, they shrink—that’s common.” For now, some mummies may hold onto some of their mystery.