After three centuries, precious guitar finally visits the doctor

Many of us encounter our first endoscopy around age 50, a colonoscopic milestone recommended by the American Cancer Society.

By that measure, the ornate 18th-century guitar that conservators brought to the Boston Medical Center last week was long overdue for a checkup.

Crafted in the 1720s, the rare guitar, which normally resides in the Raphael Room at the Isabella Stewart Gardner Museum, has definitely seen better days. Its once-sumptuous inlays depicting musical cherubs and flowers have dulled or chipped away over the centuries. Areas around the guitar’s neck and sides were clumsily restored after a particularly brutal accident long ago, and its age-dimmed wood is in need of something more than Pledge.

But it was the guitar’s mysterious innards that prompted museum conservators to bring it in for a battery of exams normally reserved for living bodies: first a CT scan, followed by the endoscopy.

“By knowing more about what’s going on with this piece structurally, we can more appropriately approach its repair and treatment,” said Holly Salmon, an objects conservator for the Isabella Stewart Gardner Museum. “It will help us understand the history of the piece.”

As a key step toward the guitar’s restoration, Salmon and her fellow conservators arrived at Massachusetts General Hospital last week for the guitar’s CT scan. Placing the instrument on a bed of towels, doctors and conservators observed as the doughnut-shaped machine delivered some 1,600 images of the guitar’s interior structure.

“This neck was yanked out of the guitar at some point,” Kevin Kelly, a Boston-based luthier, said as he watched spectral images of the guitar appear on the monitor. “Did they just paste it back in, or did they do something to reinforce it?”

The answer will be critically important to Melissa Carr, the conservator responsible for the guitar’s restoration.

“We’re not going to restring it to playing condition. The damage to the neck is too bad,” Carr said. “Right now when you look at this guitar you see what’s wrong with it, not what’s right with it. And most of it is right, but the problem is that what’s wrong with it is so distracting.”

At left, Dr. Rajiv (Raj) Gupta and Holly Salmon examine the rare guitar. Barry Chin/Globe Staff/Globe Staff

Made by the obscure luthier Jacopo Mosca Cavelli, the precious guitar is a particularly ornate example of a “chitarra battente,” a metal stringed instrument more often associated with street musicians. Boasting a rich inlay of tortoise shell, bone, and mother of pearl, the instrument has a distinct clover-shaped sound hole ornamented with an intricately carved lattice of walnut.

What makes the 14-string guitar even more rare, however, is that it’s one of only two known instruments by the Perugia, Italy-based Cavelli. An inlay on the headstock bears his name. The other — in playing condition, even more ornate, and sharing many decorative elements with the Gardner guitar — resides some 200 yards away at the MFA.

“We know nothing about this maker other than the existence of these two guitars,” said Darcy Kuronen, curator of musical instruments at the Museum of Fine Arts, who’s currently researching both instruments. “They have a lot of similarities. On the headstock [of each] are these emblems from two aristocratic families in Rome. Were they supporters of this maker? Were they made for a marriage?”

As doctor Rajiv Gupta scrolled through images that showed the guitar in millimeter-thick slices, other mysteries emerged. Conservators wondered about a strange structural post inside the instrument. They puzzled about whether all three nails that attached the neck were original. A hushed excitement filled the air as a pair of ridges flashed on the inside of the guitar. Could they be labels affixed by the maker?

The conservators hoped to answer some of these questions a few days later when they donned hairnets and medical attire for the endoscopy.

Entering the side of the instrument, the probe sent back video from what looked like a subterranean snow globe, as three centuries of dust mites whirled to reveal a label.

“All of a sudden we see the word ‘Mosca,’ ” said Salmon, who added that there was a “2” just below the name, which she believed was part of a date.

Dr. Rajiv (Raj) Gupta examined a scan of the rare guitar.Barry Chin/Globe Staff/Globe Staff

The researchers found two other labels (probably attached during a subsequent repair), as well as what appeared to be strips of parchment with script lining the back of the guitar.

“The script may have had some music notes written on it,” said Salmon, adding that they’d call on an Italian speaker to help translate the writing.

Many museums have performed similar operations on ancient objects such as mummies, and CT scans are increasingly common in the world of high-end instrument sales.

“Especially for string instruments,” violinmaker Kelly said. “I’ve heard of deals that are dependent on the results of the CT scan. There are things that can affect the value, and violin restorers are so good at hiding them.”

Over the next several weeks, Carr will use the information to guide her restoration of the guitar.

The project is part of a much broader restoration of the Raphael Room itself, which is receiving a new floor in addition to conservation work on the room’s paintings, sculptures, and decorative arts.

“These were extraordinary measures,” Salmon said of the guitar’s medical adventures. “We’ll start to be able to put together a picture of who this luthier was.”

Technicians and conservators probe a guitar from the 1720s with an endoscopy device.

Technicians and conservators probe a guitar from the 1720s with an endoscopy device.