Medical News & Perspectives - December 24/31, 1997 CT Scans Probe Secrets of Italian Masters' Violins IT STARTED in 1988 when radiologist Steven A. Sirr, MD, took along his violin to pass the time while on weekend duty at a local hospital. After performing a computed tomographic (CT) scan on an accident victim, Sirr wondered what a scan of his violin would look like. In the 9 years that followed his first violin CT scan, Sirr and his colleagues have used CT to probe the secrets of some of the rarest and most beautiful stringed instruments ever made, including 4 Stradivarius violins and other masterpieces. Speaking earlier this month at the 83rd Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA), in Chicago, Ill, Sirr, who is in practice with Consulting Radiologists, Ltd, Abbott Northwestern Hospital, Minneapolis, Minn, described the results of his studies. To date, he and several colleagues have scanned more than 30 instruments, including 14 recognized masterpieces. According to Sirr, their investigation shows that CT scanning is not only a powerful tool for acoustical studies of these instruments, it can also assist in detecting forgeries, identifying lost or stolen instruments, preventing insurance fraud, and detecting hidden flaws that can greatly reduce the value of an instrument. To correlate what can be measured by a CT scan with the actual dimensions and wood densities of an instrument, Sirr sacrificed a student-grade violin, sectioning it and carefully measuring the dimensions and density of each section. The data closely matched what was obtained by CT scans, he reported (Radiology. 1997;203:801-805). Scanning provides the modern luthier and acoustical scientist with a unique, noninvasive tool for obtaining important qualitative and quantitative information on the structure of rare stringed instrumentsÑenabling in-depth examination that otherwise might not be permitted by their owners, Sirr said. He explained: "CT evaluation is a noninvasive way to image, measure, and study components of intact violins and other bowed stringed instruments. CT scanning can be used to safely obtain high-resolution transaxial, coronal, and sagittal images of the anatomy of instruments. CT scans can detect internal 'pathology' of valuable instruments, including hidden cracks, warping, wormholes, and previous repairs not detectable by visual inspection. In addition, it provides a totally noninvasive way of making highly accurate measurements of wood thickness and density." The scans also may assist violin makers in selecting the best wood to make their instruments, he said, allowing the luthier to see internal defects and grain structure in the wood before he or she spends many hours cutting, carving, and working the piece. 'New Way of Looking' Excited by what he saw in his first CT scan of a violin, Sirr took the image to John R. Waddle, a violin maker in St Paul, Minn, who had sold him the instrument. "I never saw anything like it," Waddle said in a recent interview. "It was a totally new way for me to look at a violin. The glue lines and areas of previous repairs were immediately visible, and the more I looked the more I realized how useful CT imaging could be for studying violins and other stringed instruments." Since then, Waddle, a coauthor of the RSNA study, has designed several violins, violas, and cellos using information revealed by CT studies. "I totally changed some things based on CT images of the fine old instruments," he said. "I used to make the plates of my instruments thicker along the edges. I've departed from what I was taught and now make the plates thinner along the edges and gradually thicker toward the middleÑmore like the instruments of the old masters." In 1996, a viola of his design was awarded a gold medal for craftsmanship and quality of sound at the Violin Society of America's 12th International Violin Makers Convention in Albuquerque, NM. "We're just beginning to use this medical imaging technology to study stringed instruments," Waddle said. "I think there's a lot more we will be able to do with it that we haven't even thought of, especially since the technology is rapidly improving." Sirr and Waddle are now trying to get permission from the Smithsonian Institution in Washington, DC, to scan some of the institution's collection of more than 400 rare stringed instruments. "Our long-term goal is to establish an archive of CT scans for all the world's major stringed instruments for the use of acoustical scientists, instrument makers, collectors, and other interested parties," Sirr said. Wormholes, WarpingÑAll Revealed Among the instruments already scanned by Sirr and colleagues were 4 crafted by Antonio Stradivari (1672, 1698, 1702, and 1720), a violin by Nicolo Amati (1654), a violin by Andrea Guarneri (1633), and a cello by Domenico Montagnana (1730). Some of these instruments are valued at more than $1 million. [Coronal computed tomographic scan of a violin crafted by Antonio Stradivari reveals the instrument's rib outline and corner blocks. The scan offers the modern luthier exact measurements and shape of the the master instrument. The dot near the middle of the violin is the round spruce sound post that transmits vibrations between the violin's front and back plates. Reprinted with publisher's permission (Radiology. 1997;203:801-805). Source: Steven A. Sirr, MD/Radiology] Damage to these instruments can greatly diminish their tonal quality and value. For example, a crack in the soundpost region of a rare violin's backplate can decrease the value by half, Sirr said. The CT study revealed defects in all 14 masterpieces, including cracks, wormholes, air gaps, and warping, as well as glue lines, filler material, or other evidence of previous repair. The scans provide a high-resolution picture of the internal wood grain patterns, which are unique "fingerprints" by which these instruments can be identified. "We believe that CT evaluation of soloist-quality, bowed stringed instruments should be considered prior to consideration of purchase," Sirr said. "CT may also play an important role when insuring extremely rare and precious instruments." Imperiled by the Plague Origination of the violin, viola, and cello is credited to Andrea Amati (1511?-1580?) of Cremona, Italy, who established both a family dynasty and the Cremona school of violin making. The instruments he developed were far superior in sound and appearance to anything that came before; no other stringed instrument had their tone, volume, and ease of response. His were the instruments chosen to entertain royalty at the French court. But the most esteemed of the Amati luthiers was Andrea's grandson, Nicolo (1596-1684), whose violins continue to be among the most highly regarded by collectors and virtuosos. Few people realize how close the art of violin making came to being extinguished by the bubonic plague that swept through Cremona around 1630, killing many of its inhabitants. The victims included Nicolo Amati's parents and 2 sisters. By the time the Black Death subsided, Nicolo was the last violin maker of any consequence still alive in Italy. According to music historian Charles Beare, had Nicolo also perished, the art of violin making may have been lost before achieving its highest eminence and greatly influencing the development of the modern orchestra and western music (New Groves Dictionary of Musical Instruments. New York, NY: Groves Dictionaries; 1984). It was as apprentices in Nicolo Amati's shop that many of Cremona's foremost violin makersÑAndrea Guarneri, Francesco Ruggeri, Giovanni Baptista Rogeri, Giacomo Gennaro, and the most acclaimed of all, Antonio Stradivari (1644-1737)Ñlearned the Amati family's violin-making secrets. In a career lasting more than 70 years, Stradivari crafted more than 1100 violins, violas, cellos, and other stringed instruments. Of these, about 650 instruments are known to exist (along with thousands of imitations and counterfeits). For more than 250 years, Stradivari's designs have served as models for luthiers. Many but not all authorities today still claim that the best of the old Cremona masterpieces have not been equaled in sound by contemporary instruments. Certainly, those who already own or deal in these masterpieces profit by this belief. Nevertheless, many modern instrument makers and their customers argue that instruments are being made today that equal and possibly even surpass the work of the Italian masters. There is no disagreement, however, that it has taken more than 2 centuries for the art of violin making to catch up to where it was when Stradivari and other Cremona masters applied their closely kept secrets to string and wood. Sirr and Waddle believe these old instruments still hold secrets, secrets that may finally be revealed with the help of CT technology. Ñby Andrew A. Skolnick (JAMA. 1997;278:2128-2130)