Faculty Bibliography

OBJECTIVE: The purpose of this study was to show the ability of power Doppler sonography (PDS) to evaluate exercise-induced changes in muscle blood volume. SUBJECTS AND METHODS: We evaluated 20 biceps muscles with PDS in 10 healthy volunteers before and after they underwent a standardized exercise protocol. Intramuscular blood volume was qualitatively analyzed using a subjective scoring system to evaluate vascular conspicuity, comparing sonograms obtained before and after exercise. We also collected preliminary data on the quantification of estimated fractional moving blood volume (EFMBV) measured on sonograms obtained in eight biceps muscles of five volunteers. Assessment of significance was calculated using a Wilcoxon signed-rank correlation of significance. The stability of relative changes in EFMBV was also assessed with measurements performed at three different times in five healthy volunteers. RESULTS: With exercise, all 20 biceps muscles showed a significant subjective increase in apparent vascularity (p < .0005). Likewise, preliminary data on EFMBV showed significant increases (p < .01) between baseline and peak exercise values (mean, 470%; range, 180-900%). CONCLUSION: PDS revealed marked increases in intramuscular vascular conspicuity after exercise. EFMBV provided a potentially useful parameter to document such increases quantitatively.

We measured the incidence of cuff retear and injury to the suprascapular nerve after mobilization and repair of a massive rotator cuff tear. Of one hundred four rotator cuff repairs performed over a 5-year period, 10 patients (7 men and 3 women, age range 22 to 68 years) had primary repairs of massive rotator cuff tears requiring cuff mobilization and an acromioplasty as their only procedure. These patients were evaluated at a mean of 2.5 years (range 2.0 to 3.0 years) after surgery. At follow-up electromyographic examination confirmed that 1 of the 10 patients had an iatrogenic suprascapular nerve injury, whereas ultrasound evaluation revealed that 2 of 10 repairs failed. Pain relief was achieved in the eight patients with intact repairs and not in the two with recurrent tears. All patients had some limitation of active motion or strength, especially in external rotation. Thus 7 of 10 patients had neither evidence of nerve injury nor recurrent rotator cuff tears yet still showed limited active motion or weakness. It appears that operative injury to the suprascapular nerve during cuff mobilization can occur, but other factors such as inadequate cuff muscle function are more frequently responsible for the poor functional outcomes seen after successful repairs of massive rotator cuff tears.

We describe a patient with unexplained hypercalcemia who under went bone scintigraphy, which demonstrated marked tracer uptake within the hilar lymph nodes. The pattern strongly suggested sarcoidosis, which was subsequently confirmed by bronchoscopy-directed biopsy.

The majority of adults over the age of 65 y develop osteoarthritis (OA), a joint disease characterized by degeneration of articular cartilage and subchondral sclerosis. Early in the disease, the articular cartilage surface begins to change histologically from a smooth to a rough or fibrillated appearance. A prerequisite for any chondroprotective pharmacological intervention is detection of OA in its preclinical phase. Current diagnostic imaging modalities, such as radiographs or (nuclear) magnetic resonance imaging, either cannot directly image the cartilage surface or lack sufficient resolution to detect surface fibrillations. We have developed an ultrasonic technique that can be used to characterize these surface fibrillations directly. We present our in vitro results with validation by laser-based confocal microscopic imaging.

Evaluation of a painful total knee replacement has been limited to physical examination, aspiration, plain radiographs, and radionuclide studies. Visualization of the polyethylene tibial-bearing component without surgery has not been possible. Polyethylene wear is a well-recognized cause of total knee replacement failure. We have developed an ultrasound method to evaluate polyethylene insert shape and thickness with the ability to clearly demonstrate structural loss of plastic. Before clinical trials, a total knee replacement was cemented into a fresh cadaver knee. Ultrasound imaging of the polyethylene insert was performed in the longitudinal plane using a 10 MHz linear transducer. A characteristic bone/metal/polyethylene interface enabled recognition of the insert material from which its dimension was estimated. The entire perimeter of the liner, the metal tray, and the bone-metal interface was visualized. Five consecutive measurements at each location were performed on each of the 8-, 10-, and 12-mm polyethylene liners with the ultrasonographer blind to the insert thickness. Once removed, measurements were made directly on the liners adjacent to the marked points with an electronic caliper. Coefficient of variation (r2) ranged from 1.6% to 8.3% for the ultrasound measurements, and 0.26% to 1.5% for the caliper measurements. A plot of ultrasound versus caliper measurements allowed calculation of a linear equation, with r2 = 0.98, demonstrating high correlation between the two measurements. Our ultrasound measurements are accurate to 0.5 mm with a 95% confidence interval. Ultrasound is an accurate way to measure the dimensions of the polyethylene liner in total knee replacement arthroplasty. Early experiences with ultrasound evaluation prior to revision have been very encouraging for the evaluation of polyethylene wear, defects, and of prosthetic loosening.

OBJECTIVE: The aim of this study was to demonstrate the use of ultrasound guidance in confirming intralesional injection of corticosteroids and local anesthetic into symptomatic ganglia, and to propose potential advantages of this technique. DESIGN AND PATIENTS: Ten patients (five men, five women) underwent ultrasound-guided injection of a ganglion. Seven ganglia were near the wrist, one was adjacent to a finger interphalangeal joint and two were adjacent to the talus. All were injected with a 1:1 mixture of long-acting corticosteroid and local anesthetic, the actual volume being dependent on the size of the ganglion. Three patients had a second injection 9-18 months following the initial injection. RESULTS: In four patients the ganglia resolved completely. In five patients there was significant improvement, with a reduction in size of the ganglion and symptomatic relief. CONCLUSION: Ultrasound-guided injection insures intralesional deposition of corticosteroids and may provide an alternative to surgery in the management of ganglia.

OBJECTIVE: Power Doppler sonography is a relatively new technique that has been shown to depict hyperemia associated with musculoskeletal inflammatory disease. We performed this study to evaluate the ability of power Doppler sonography to differentiate musculoskeletal fluid collections of varying etiologies. SUBJECTS AND METHODS: Gray-scale and power Doppler sonography were performed on 39 patients with joint effusions or appendicular fluid collections. Blood flow (hyperemia) in the soft tissues adjacent to the fluid collections was subjectively analyzed and graded on a scale of 1 to 4 (1, normal flow; 2-4, increasing degrees of hyperemia). All fluid collections were aspirated within 24 hr of the sonographic examination. We found 31 joint effusions and 12 periarticular collections with appropriate imaging and pathologic correlation. RESULTS: Adjacent to 36 effusions and fluid collections, we saw moderate or marked hyperemia. Thirty-five of the 36 had an inflammatory or neoplastic cause, including 15 infected collections. One fluid collection had a degenerative etiology (subdeltoid bursitis secondary to supraspinatus tendon tear). Adjacent to the seven remaining effusions and fluid collections, we saw normal or mildly increased hyperemia; none of these collections had an inflammatory etiology. CONCLUSION: Power Doppler sonography helps distinguish inflammatory and infectious musculoskeletal fluid collections from those that are noninflammatory, and it may help guide the decision to perform diagnostic aspiration. Power Doppler sonography does not reliably differentiate between inflammatory collections of infectious and noninfectious origin because collections of either origin may significantly increase adjacent soft-tissue perfusion.

Magnetic resonance imaging of the knee was performed in 28 patients (ages 15-72 years), using a 1.5-T unit. Volume gradient echo (3D GRASS) acquisition with and without presaturation off-resonance RF pulse was used to evaluate magnetization transfer (MT) effects, determined by placing regions of interest on muscle, fat, hyaline, and fibrocartilage; the percent change in signal intensity was calculated and compared using a paired two-sample t test. An in vitro study of the normal meniscus from a cadaver containing a scalpel cut extending to an articular surface was performed to observe the relative improvement in contrast in the presence of a small meniscal defect. MR imaging of the specimen was performed using an Omega CSI 2.0-T system (General Electric Medical Systems, Fremont, CA). Analysis of clinical images resulted in signal loss, compared to that of the identically timed and tuned non-MT images of 47 +/- 5, 8 +/- 5, 49 +/- 5, and 57 +/- 7% for muscle, fat, articular cartilage and fibrocartilage, respectively. Application of MT improved the depiction of the artificially introduced meniscal defect. Meniscal fibrocartilage demonstrates significant MT effect after application of off-resonance RF presaturation, which may improve visualization of meniscal defects.

Power Doppler sonography was used in eight symptomatic knees in seven patients with arthritis before and after joint aspiration and intraarticular administration of steroids. A qualitative decrease in synovial perfusion was observed in all eight knees, and symptoms improved in seven of the eight cases. These preliminary data suggest a role for power Doppler sonography in assessment of serial changes in synovial inflammation.

A projection-operator technique is applied to a general three-component model for magnetization transfer, extending our previous two-component model [R.S. Adler and H.N. Yeung, J. Magn. Reson. A 104, 321 (1993), and H.N. Yeung, R. S. Adler, and S.D. Swanson, J. Magn. Reson. A 106, 37 (1994)]. The PO technique provides an elegant means of deriving a simple, effective rate equation in which there is natural separation of relaxation and source terms and allows incorporation of Redfield-Provotorov theory without any additional assumptions or restrictive conditions. The PO technique is extended to incorporate more general, multicomponent models. The three-component model is used to fit experimental data from samples of human hyaline cartilage and fibrocartilage. The fits of the three-component model are compared to the fits of the two-component model.