PubMed Health⌕ Search

Biomedical subjects

R S Adler

Publications and source records attributed to R S Adler.

At least 19 recordsLinked to original sources
PubMed1998

Pediatric hip effusions: evaluation with power Doppler sonography.

PURPOSE: To determine if power Doppler sonography allows differentiation of infectious from noninfectious hip effusions and thereby obviates joint aspiration. MATERIALS AND METHODS: Twenty-nine consecutive children (30 hips) with sonographically identified hip effusion were prospectively evaluated with power Doppler sonography. Both hips were evaluated in each patient by using identical imaging parameters and were then compared. Medical charts were reviewed to determine the eventual diagnosis. RESULTS: At power Doppler sonography, none of 16 patients with transient synovitis had increased flow in the affected hip compared with the contralateral normal hip. Of 11 patients with septic arthritis, one had asymmetric increased flow, and two others, in whom contralateral comparison images were limited, had probable increased flow. Three patients with miscellaneous diagnoses had symmetric normal flow. CONCLUSION: Because power Doppler sonograms did not depict increased flow in most patients with septic arthritis, normal flow on power Doppler sonograms does not allow exclusion of septic arthritis and should not preclude aspiration when clinically warranted.

Adolescent↗
PubMed1998

Sonographic detection of xanthomas in normal-sized Achilles' tendons of individuals with heterozygous familial hypercholesterolemia.

OBJECTIVE: The objective of this study was to evaluate how well high-frequency linear array sonography reveals xanthomas in the Achilles' tendons of individuals with heterozygous familial hypercholesterolemia before the xanthomas enlarge the tendons enough to become palpable. SUBJECTS AND METHODS: Both Achilles' tendons of 23 individuals (18 female and five male; age range, 16-69 years old) who had heterozygous familial hypercholesterolemia but no clinically apparent Achilles' tendon xanthomas were studied with high-frequency linear array sonography. Hypoechoic areas, consistent with xanthomas, were noted. RESULTS: Xanthomas were revealed in 36 (78%) of 46 tendons and 19 (83%) of 23 individuals. CONCLUSION: Sonography reveals Achilles' tendon xanthomas in many individuals with heterozygous familial hypercholesterolemia before the xanthomas are clinically apparent. Because tendon xanthomas in a hypercholesterolemic individual are essentially pathognomonic of heterozygous familial hypercholesterolemia and are a mainstay in its diagnosis, our study suggests that sonography is useful in the early diagnosis of heterozygous familial hypercholesterolemia.

Achilles Tendon↗
PubMed1998

Power Doppler sonography in tenosynovitis: significance of the peritendinous hypoechoic rim.

The aim of this study was to evaluate the ability of power Doppler sonography to distinguish between hypoechoic fluid and synovium in patients with suspected tenosynovitis. Gray scale sonography and power Doppler sonography were performed on 26 tendons in 24 patients with tenosynovitis and 30 tendons in five asymptomatic volunteers. Peritendinous blood flow was graded on a scale of 0 to 3 and the percentage of the hypoechoic rim that contained blood flow was also noted. In the symptomatic group, flow was demonstrated in more than 50% of the peritendinous hypoechoic rim in 17 of 26 tendons. A positive correlation was found between the power Doppler sonographic grade and the percentage of the rim that had flow. These results suggest that a significant proportion of the hypoechoic rim probably represents vascularized synovium rather than complex fluid.

Adult↗
PubMed1997

Ultrasonic characterization of in vitro osteoarthritic articular cartilage with validation by confocal microscopy.

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.

Adult↗
PubMed1997

Normalizing fractional moving blood volume estimates with power Doppler US: defining a stable intravascular point with the cumulative power distribution function.

PURPOSE: To normalize the power Doppler ultrasound (US) signal to the expected signal from 100% blood in the calculation of a fractional moving blood volume estimate. MATERIALS AND METHODS: To locate the signal from flowing blood with a consistent backscatter coefficient, the authors estimated the knee of the cumulative Doppler power distribution function. They used a flow-tube phantom to test the use of this knee to locate a radial position that would fall into a region of high shear stress and minimal rouleaux formation. They also studied how well the method normalized fractional moving blood volume estimates of the right renal cortex in a volunteer when simulating different body habitus and in a group of six healthy volunteers to estimate variability. RESULTS: Over five flow velocities and over undersaturated to severely oversaturated receiver gains, the calculated flow-tube area was a mean 89% +/- 7 (+/- standard deviation) of a standard. In humans, the technique normalized the fractional moving blood volume estimates over an 8-dB receiver gain variation; the mean +/- standard deviation of fractional moving blood volume estimates for the six volunteers was 37.6% +/- 3.6. CONCLUSION: Vascularity estimates with power Doppler US are feasible with a normalization scheme based on the cumulative Doppler power distribution function.

Adult↗
PubMed1997

Power Doppler sonography: use in measuring alterations in muscle blood volume after exercise.

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.

Adult↗
PubMed1997

Technetium-99m-MDP uptake in hilar lymph nodes in sarcoidosis.

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.

Adult↗
PubMed1996

The effect of magnetization transfer in meniscal fibrocartilage.

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.

Adolescent↗
PubMed1996

A three-component model for magnetization transfer. Solution by projection-operator technique, and application to cartilage.

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.

Adult↗
PubMed1996

Ultrasound-guided injection of ganglia with coricosteroids.

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.

Adult↗
PubMed1996

Autocorrelation of integrated power Doppler signals and its application.

The integrated power Doppler signal arising from blood flow is a random process. In this article, a general approach to model this random process is studied. Both the theoretical and experimental results show that the temporal autocorrelation function of the integrated power Doppler signals is directly related to properties of the insonified medium, such as the scattering strengths and velocities of all moving scatterers, and as well as the properties of the Doppler imaging system, such as the point spread function (psf) of the power Doppler images. Some initial experiments are performed to test the proposed model. Its potential application for flow measurement, such as perfusion evaluation, is also discussed.

Blood Flow Velocity↗
PubMed1996

The hemodynamics of transjugular intrahepatic portosystemic shunts: investigations with Doppler sonography and development of an in vitro model.

RATIONALE AND OBJECTIVES: We evaluated Doppler sonography-based measurements of transjugular intrahepatic portosystemic shunt (TIPS) function and developed an in vitro model of normal TIPS hemodynamics. METHODS: We reviewed retrospectively the results of all trans-TIPS manometries (N = 116) performed during a 24-month period. Portosystemic pressure gradient was compared with peak stent velocity as measured by angle-corrected Doppler sonography. A flow phantom simulating TIPS was created using 8-, 10-, and 12-mm-diameter wire-mesh stents placed in cylindrical channels with lengths ranging from 3.4 to 6.0 cm. RESULTS: Among 50 trans-TIPS manometries with corresponding Doppler sonography performed on well-functioning shunts, measured portosystemic pressure gradient and peak velocity were not correlated (R2 = .014). On the basis of a regression of measurements in the flow phantom, pressure loss in a stented cylindrical channel was estimated as follows: delta p = rho.(0.145 -0.001.Rey + 0.816.L/D).(Vmean2/2), where rho is the fluid density, Rey is the Reynolds number, L is the channel length, D is the stent diameter, and Vmean is the time-averaged velocity within the stent. Predicted and measured pressure gradients were correlated (R2 = .91). CONCLUSION: Peak velocity in patients with a normally functioning TIPS does not predict the magnitude of the portosystemic pressure gradient.

Blood Flow Velocity↗
PubMed1996

Power Doppler sonography of synovitis: assessment of therapeutic response--preliminary observations.

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.

Adult↗
PubMed1996

Power Doppler sonography in the assessment of musculoskeletal fluid collections.

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.

Adult↗
PubMed1996

An ultrasound method to evaluate polyethylene component wear in total knee replacement arthroplasty.

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.

Anthropometry↗
PubMed1995

Ultrasonic estimation of tissue perfusion: a stochastic approach.

Imaging of blood flow perfusion is an area of significant medical interest. Recently, the advantages of using the total integrated Doppler power spectrum as the parameter that is encoded in color has been shown to result in an approximately threefold increase in flow sensitivity, a relative insensitivity to acquisition angle and lack of aliasing. We have taken this mode a step further and demonstrated the potential for quantifying blood flow using correlation-based algorithms applied to the power signal. We show that phi(tau) = phi(0)e-VT, where phi(tau) is the two-time correlation of the fluctuation in the power signal, and v is the specific flow (reciprocal of mean transit time). Scans of a dog's blood, pumped at a constant rate through gum rubber tubing, were obtained using a Diasonics Spectra 10-MHz linear array transducer at standard range-gated spectral mode (PRF = 1400 Hz, wall filter = 50 Hz, sample gate = 1.5 mm). A fixed Doppler angle of 68 degrees was used. Five different flow rates were tested, and the velocities determined by power decorrelation were compared to the mean velocities calculated from the Doppler shifts by linear regression (R2 = 0.987). We believe the results are very encouraging for using power decorrelation in perfusion evaluation.

Algorithms↗
PubMed1995

Ultrasound tissue displacement imaging with application to breast cancer.

A method for quantitative imaging of internal tissue motion based on speckle tracking is described. Tissue displacement images from eight patients with sonographically apparent breast masses are used to illustrate the technique. The local displacement response of tissues surrounding malignant and benign breast masses is compared, testing the hypothesis that altered mechanical properties may result in motion signatures for many soft tissue tumors relative to their host tissue. In addition, the potential or anticipated influence of various biological and physical factors on tissue motion response is discussed.

Adult↗