Computed tomography of humans and bowed stringed instruments. Some interesting similarities.

We have used computed tomography to evaluate bowed stringed instruments and have noted interesting analogies with CT scans of humans. In humans, CT commonly detects a broad range of normal anatomic variations. Similarly, CT of violins and cellos demonstrates a wide range of normal structural variations. CT, often used to detect infections in humans, also detects defects from wood infestations. In humans, the unrelenting effect of gravity causes deformity of the demineralized spine. In old stringed instruments, plastic deformity of wood results from unrelenting string pressure. Trauma causes bone fractures in humans and wood fractures in bowed stringed instruments, and repairing fractures in both humans and stringed instruments requires various splitting devices. In summary, CT provides the physician and the luthier with a unique, noninvasive tool that can characterize the broad range of normal structures, pathological conditions, and repair.

Use of CT in detection of internal damage and repair and determination of authenticity in high-quality bowed stringed instruments.

Computed tomography (CT) was used to evaluate 17 high-quality violins and cellos crafted between 1633 and 1872 by master craftsmen such as Guarneri, Amati, and Stradivari. Multiple high-resolution CT scans were obtained in each instrument, and additional scans were obtained when defects or repair was detected. Varying degrees of internal damage (eg, wormholes, air gaps, plastic deformities of wood) or repair (eg, glue lines, filler material, wooden cleats and patches) not seen at visual inspection were detected in all 17 instruments. In addition, CT allowed noninvasive identification of the internal wood grain pattern unique to each instrument, thereby facilitating verification of authenticity to help protect against loss, theft, or forgery. The information provided by CT analysis of valuable bowed stringed instruments may prove useful to prospective buyers or to insurance companies that specialize in insuring such instruments against accidental loss or damage.

CT analysis of bowed stringed instruments.

PURPOSE: To determine the utility of computed tomography (CT) for the noninvasive evaluation of bowed stringed instruments. MATERIALS AND METHODS: Thirty-seven instruments that ranged in quality from student instruments to exquisite Stradivarius violins were analyzed with CT. Accuracy of thickness measurements was determined from 24 measurements of cross-sectional pieces sawed from a student violin. Accuracy of density measurements was determined from 328 CT attenuation measurements of 16 woods used in stringed instruments. RESULTS: Substantial differences of normal structure were noted between the masterpieces crafted in Cremona, Italy, and factory-produced student instruments. Unexpected defects were detected in nine of 14 instruments older than 100 years and ranged from a few wormholes (eight instruments) to many wormholes and extensive repair (one violin). CT thickness and attenuation measurements correlated well to the line of identity with actual measurements (P < .0001). Two cellos and a viola have been constructed from CT-derived information. The viola was awarded a gold medal at a recent international competition. CONCLUSION: CT provides the modern luthier and acoustic scientist with a unique tool for characterization of normal structure, defects, and repair and for accurate measurements of wood thickness and density. CT-derived information aids in the replication of original masterpieces. CT evaluation may have an important role in the valuation, insurance, and identification of valuable stringed instruments.

Effects of mild exercise on cytokines and cerebral blood flow in chronic fatigue syndrome patients.

Chronic fatigue syndrome (CFS) is an idiopathic disorder characterized by fatigue that is markedly exacerbated by physical exertion. In the present study, we tested the hypothesis that mild exercise (walking 1 mph [1 mile = 1.609 km] for 30 min) would provoke serum cytokine and cerebral blood flow abnormalities of potential pathogenic importance in CFS. Interleukin-1 beta, interleukin-6, and tumor necrosis factor alpha were nondetectable in sera of CFS patients (n = 10) and healthy control subjects (n = 10) pre- and postexercise. At rest, serum transforming growth factor beta (TGF-beta) levels were elevated in the CFS group compared with the control group (287 +/- 18 versus 115 +/- 5 pg/ml, respectively; P < 0.01). Serum TGF-beta and cerebral blood flow abnormalities, detected by single-photon emission-computed tomographic scanning, were accentuated postexercise in the CFS group. Although these findings were not significantly different from those in the control group, the effect of exercise on serum TGF-beta and cerebral blood flow appeared magnified in the CFS patients. Results of this study encourage future research on the interaction of physical exertion, serum cytokines, and cerebral blood flow in CFS that will adopt a more rigorous exercise program than the one used in this study.

Therapeutic embolization: enhanced radiolabeled monitoring.

Radiolabeling of Ivalon (polyvinyl alcohol sponge) particles permits localization of injected particles during embolization through the use of a portable gamma camera and provides a means to prevent potentially fatal complications such as pulmonary embolization. A more efficient technique of labeling Ivalon particles with technetium-99m sulfur colloid was developed. An increase in labeling efficiency allowed more accurate determination of the distribution of injected Ivalon particles. Scanning electron microscopy demonstrated the stability of the Ivalon particles during this new labeling process. Two patients with arteriovenous malformations underwent therapeutic embolization with radiolabeled Ivalon particles; gamma camera imaging of the lesion and chest was performed throughout the procedure.

An improved radiolabeling technique of ivalon and its use for dynamic monitoring of complications during therapeutic transcatheter embolization.

Transcatheter embolization by Ivalon particles for treatment of arteriovenous malformations has been an accepted therapeutic technique for many years. We describe a new and efficient radiolabeling technique of Ivalon particles using [99mTc]sulfur colloid. Continuous and dynamic monitoring of injected radiolabeled Ivalon particles is made possible by viewing the persistence scope of a portable gamma camera whose head is positioned over the patient undergoing therapeutic embolization. Therefore, if inadvertent pulmonary embolism or reflux migration of radiolabeled Ivalon particles has occurred, the angiographer is immediately aware of this potentially serious or fatal complication and can take corrective action. We describe two patients, each with an arteriovenous malformation, who had therapeutic embolization with radiolabeled Ivalon particles, one resulting in reflux migration and the other resulting in inadvertent pulmonary embolism.

Acute recurrent appendicitis with appendicolith.

Appendiceal disease can be acute, acute recurrent, or chronic. Acute appendicitis is the most common form. Acute recurrent appendicitis is more common than chronic appendicitis. In children the clinical manifestations of appendicitis are variable. Patients who have an appendicolith usually develop appendicitis, often with perforation. A case is presented of 3-year follow-up of a patient with an appendicolith and acute recurrent appendicitis. The literature about appendicoliths is reviewed. In the appropriate clinical setting, a history of prior episodes of similar right lower quadrant pain does not preclude the diagnosis of appendiceal disease. Awareness of the less common forms of appendicitis is important so that appropriate treatment is not delayed.

Peripheral embolization of diffuse hepatic arteriovenous malformations in a patient with hereditary hemorrhagic telangiectasia.

Ivalon particles were used for hepatic arterial embolization of diffuse arteriovenous malformation in a patient with hereditary hemorrhagic telangiectasia. The methods of the procedure and possible complications are discussed.

Aerosol penetration ratio: a new index of ventilation.

Superimposition of nuclear medicine scintigrams and standard radiographs provides a unique opportunity for merging functional information intrinsic to nuclear medicine images with the high resolution anatomic detail of radiographs. A newly developed image processing system allows the merging of two separate films of greatly varying sizes to form a single composite image. Subsequent quantitative analysis of the composite image may be performed. Using the superimposition technique, [99mTc]DTPA aerosol ventilation scans (4.5 X 4.5 cm) were superimposed upon chest radiographs (35.6 X 43.2 cm) in 17 cystic fibrosis (CF) patients. Subsequent quantification of the area of nuclear scan ventilation and the radiographic lung area was then performed. A new quantitative radiologic index of ventilation, the aerosol penetration ratio (APR), was defined. Linear correlation of aerosol penetration ratio with residual volume (RV) as percent of total lung capacity (TLC) measured by body plethysmography was good. We conclude that the APR has validity as a physiologic parameter which localized regional excessive residual volume and correlates well with RV/TLC, the "gold standard" pulmonary function index of obstructive airway disease.

Airflow measurement inaccuracies in aerosol imaging.

Aerosol production using inclined compressed air tanks may be subject to error caused by airflow meter variability and by the degree of inclination of the air-flow meter. Since most of these tanks are used in an inclined position, it is important for clinicians to be aware of these errors.

The preliminary evaluation of Mn DTPA as a potential contrast agent for nuclear magnetic resonance imaging.

The pharmacokinetics of 54Mn administered as Mn-diethylenetriamine pentaacetic acid (DTPA) are being investigated to determine if tissue-specific uptake of manganese could be observed while increasing urinary excretion. This chelation and increased excretion should reduce toxicity. In order to obviate the need for repetitive quantitative nuclear magnetic resonance imaging (NMR) we have substituted tracer amounts of a radioisotope of manganese, Mn-54, for the stable ion. By 6 hours, 58 +/- 7% of the injected dose had been excreted in the urine. Peak liver accumulation occurred within 30 minutes (0.50 +/- 0.14% injected dose/g X kg body weight). The pancreas also showed a relatively high accumulation of tracer (0.25 +/- 0.04%/g X kg body weight), reaching a peak at 4 hours. The pancreas to liver ratios were highest at 6 hours (0.7). There was also a substantial accumulation of the manganese in bile. The blood concentration fell very rapidly with little tracer remaining in the blood at 1 hour. Based on these pharmacokinetics, imaging experiments were conducted before, immediately after, and 9 or 24 hours postinjection. These images showed enhanced kidneys and, later (at 9 hours), an excellent parenchymal-collecting system differentiation. The gallbladder was negatively enhanced. The liver showed either increased or decreased signal strength relative to skeletal muscle depending on the pulse sequence used. We conclude that Mn++, administered as Mn-DTPA, merits further investigation as an NMR contrast agent.

Effect of ethanol on droplet size, efficiency of delivery, and clearance characteristics of technetium-99m DTPA aerosol.

With recent technical advances in aerosol technology, the study of regional ventilation using [99mTc]DTPA aerosol has become increasingly popular. Using a cascade impactor, we have assessed droplet size distribution from a newly designed nebulizer. Delivery efficiency of [99mTc]DTPA aerosol to normal subjects was improved 70% with a 10% concentration of ethanol in the nebulizer. Using filter paper fixed to the delivery end of the aerosol device, and varying ethanol concentrations from 0-10%, an 87% increase of deposited radioactivity is measured. Use of higher concentration of ethanol to the nebulizer solution did not further improve delivery efficiency. The addition of ethanol did not alter clearance characteristics of [99mTc]DTPA from the lung nor did it affect droplet size distribution.