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For Release After 11 a.m. CST, Thursday, Dec. 4, 1997

CT SCANS DETECT VIOLIN FLAWS, FORGERIES AND "FINGERPRINTS";

MAY UNLOCK SECRETS OF MASTER VIOLIN MAKERS

CHICAGO -- Serious musicians may do well to consult a radiologist before they purchase their next violin, according to a computed tomography (CT) study of 14 solo-quality stringed instruments, including rare Stradivarius violins and other acknowledged masterpieces.

The CT scans revealed unexpected defects, new information about how the instruments were constructed and distinctive "fingerprints" that can aid in identifying lost or stolen instruments, according to Steven A. Sirr, M.D., who presented the study here today during the 83rd Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA). Dr. Sirr is a radiologist at Abbott Northwestern Hospital, Minneapolis.

"Damage to these instruments -- many of which are valued at more than $1 million -- may considerably diminish the value and the tonal quality," Dr. Sirr said. "For example, a crack in the sound post region of the back plate of a violin decreases the value by 50 percent." Defects that cannot otherwise be detected can be seen on CT, he said.

The technique also may be used to identify forgeries and provide new information to violin makers who seek to craft instruments that match the quality of Stradivarius, Amati and other acknowledged masters.

"Two cellos and a viola have been constructed using CT-derived information," Dr. Sirr said. The viola, modeled after an instrument made by Giovanni Paolo Maggini and Gasparo da Salo in the early 17th century, was awarded a gold medal for craftsmanship and tonal quality at a recent international competition, he said.

CT evaluation also can identify unique internal wood grain patterns that serve as a "fingerprint" for each instrument. "We believe that CT evaluation should be considered prior to purchase of a solo-quality instrument, and may play a role in insuring these extremely rare and precious instruments," Dr. Sirr said.

CT-detected defects of varying degrees of severity in all 14 of the instruments studied included cracks, wormholes, air gaps and structural deformities. Evidence of repair, such as glue lines, filler material and wooden patches, also could be seen with CT.

"A major function of the modern violin maker, or luthier, is to appraise instruments. This is done with careful inspection of the external surfaces and, using dental mirrors, of the internal surfaces," Dr. Sirr said. "It is well known that many serious problems may be concealed with glue, filler material, retouch or varnish. These manipulations may be missed with even the most careful visual inspection, but they will be seen with CT."

Co-authors of a scientific exhibit on the topic presented by Dr. Sirr during the RSNA meeting are M. Plunkett, M.D.; L. Hassan, M.D.; J. Waddle; and M. Darnton.

The RSNA is an association of 30,000 radiologists and physicists in medicine dedicated to education and research in the science of radiology. The Society's headquarters are located at 2021 Spring Road, Suite 600, Oak Brook, Illinois 60523-1860.

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Copies of 1997 RSNA news releases are available online at http://www.pcipr.com/rsna beginning Monday, Dec. 1.