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Biomedical subjects

R S Adler

Publications and source records attributed to R S Adler.

At least 73 records · Page 4Linked to original sources
PubMed1991

Dialysis-related amyloid arthropathy: MR findings in four patients.

Dialysis-related amyloidosis is a recently recognized complication of long-term hemodialysis. It is caused by the deposition of a unique form of amyloid derived from circulating beta 2-microglobulin. This study describes the MR imaging characteristics in five articular sites of four symptomatic patients with biopsy-proved (three patients) or clinically and radiographically suspected (one patient) dialysis-related amyloidosis. Three wrists, one knee, and one cervical spine were examined. The extent of osseous and soft-tissue involvement at each joint site was well shown by MR imaging. Lesions that were apparently intraosseous on conventional radiographs were shown to be caused by well-defined erosions that extended to the articular surface. The MR signal characteristics of the amyloid deposition were intermediate between those of fibrocartilage and muscle on all sequences, distinguishing the deposition from cellular lesions or those containing large amounts of water, such as inflammatory masses, acute or chronic synovitis, and brown tumors of hyperparathyroidism. The intraarticular masses were associated with a moderate joint effusion in the large joint imaged, and small effusions were present in the wrist. Use of a fat-suppression sequence enhanced visualization of amyloid deposits within the wrist of one patient but provided no additional information in the knee of a second patient. Our experience suggests that MR imaging is well suited to showing the extent and distribution of articular disease in dialysis-related amyloidosis.

Amyloidosis↗
PubMed1991

Overview: new methods in imaging osteoarthritis.

The new imaging modalities, namely computed tomography (CT), magnetic resonance imaging (MRI), and ultrasonography (US) provide potentially powerful tools for in vivo assessment of osteoarthritis (OA), monitoring the progress of the disease and understanding its natural course. However, to use these tools effectively, we need more prospective research focused on correlating imaging data with biochemical and gross and microscopic pathologic findings. MRI is clearly the most powerful tool for demonstrating the various articular components which may be affected in OA. CT is excellent for delineating osseous abnormalities and with US we are able to evaluate the thickness and surface characteristics of those portions of articular cartilage that are accessible. The advantages and limitations of these 3 modalities are discussed as they pertain to OA of the hip and knee.

Arthrography↗
PubMed1990

Quantitative tissue motion analysis of digitized M-mode images: gestational differences of fetal lung.

Quantitative analysis of transmitted cardiac motion in fetal lung is evaluated by applying correlation techniques to digitized M-mode images in 21 patients, subdivided into two subgroups by gestational age: (I) 25-30 weeks (11 patients), and (II) greater than or equal to 35 weeks (10 patients). The corresponding numbers of M-mode images analyzed for each group are 23 and 18, respectively. This partition is expected to reflect functionally "immature" and "mature" lungs. The estimated maximum mean radial deformation per unit epicardial excursion, (r), is calculated from the two-time, spatially averaged correlation function obtained between diastolic and systolic M-mode lines. The collective results for each subgroup are (r) I = 0.79 +/- 0.11 (sem) and (r) II = 0.62 +/- 0.13 (sem). The analysis presented, albeit in a limited population, is indicative of a trend in accordance with qualitative observations of Birnholz and Farrell (1985). M-mode analysis, as indicated by Adler et al. (1989) is a potentially useful technique to quantify such tissue motion.

Female↗
PubMed1990

Transrectal ultrasound appearance of granulomatous prostatitis.

Granulomatous prostatitis is an uncommon condition that can masquerade as prostatic carcinoma on both digital rectal exam and prostate ultrasound. It occurs most often after acute urinary tract infection, transurethral prostate resection, or needle biopsy. It can be seen in systemic granulomatous diseases and after intravesical bacillus Calmette-Guerin (BCG) therapy for bladder carcinoma. In some cases it is idiopathic. Six patients who underwent transrectal ultrasound of the prostate and subsequent transrectal ultrasound-guided biopsy had histologic diagnosis of granulomatous prostatitis. One patient was undergoing BCG therapy for bladder cancer. Two patients had recent urinary tract infections. The other three patients had no known predisposing conditions. Sonographically, the glands were enlarged in five patients, with multiple large and small hypoechoic zones throughout the peripheral, transition, and central zones. The appearance was similar to that seen in diffuse prostatic carcinoma. In one patient, a solitary hypoechoic lesion in the peripheral zone, indistinguishable from carcinoma, was present. Granulomatous prostatitis should be considered in the differential diagnosis of focal and diffuse abnormality with prostatic ultrasound.

Adult↗
PubMed1990

After teen suicide: issues for pediatricians who are asked to consult to schools.

Every suicide is a unique tragedy. This article has attempted to provide a framework for understanding suicide as it impacts on the school community. Given this background, we have listed 10 frequent dilemmas faced by pediatricians (and others) who consult to schools. The central themes of the approach offered are to avoid inadvertently glorifying suicide, target high-risk groups for interventions, and consider suicide prevention as part of the broad, ongoing task of providing a caring environment for adolescents in which the collaboration of the school community is essential.

Adolescent↗
PubMed1989

Imaging of meniscal cyst of the knee in three cases.

Three cases of solitary meniscal cyst in the knee have recently been diagnosed in our departments using ultrasound and nuclear magnetic resonance (MRI). Two cysts involved the lateral and one the medial meniscus. The appearance of these lesions on ultrasound and MR images is shown. All three cysts had low intensity on T1-weighted images and high intensity on T2-weighted images and clearly communicated with a large horizontal tear in the meniscus. Ultrasonography showed a relatively hypoechoic lesion and, in the two cases of lateral meniscal cyst, focal areas of relatively increased echoes which are probably due to meniscal debris. Ultrasound showed the abnormal meniscus in both of these cases. MRI is the best way of showing the cyst and an accompanying meniscal tear but, where MRI is not available, ultrasound may be an easy and inexpensive way of making a diagnosis whether or not it is used in conjunction with positive contrast arthrography.

Adult↗
PubMed1989

Calculating radiation absorbed dose for pheochromocytoma tumors in 131-I MIBG therapy.

A protocol for calculating radiation absorbed dose to pheochromocytoma tumors during treatment with 131I-labeled metaiodobenzylguanidine (MIBG) is described. The technique calls for (a) obtaining tumor volumes from Computed Tomography and/or Magnetic Resonance Imaging, (b) computing energy absorbed by assuming complete beta-particle absorption and a standard shape for gamma-ray absorption and (c) scaling from tracer to therapy dose rate by the ratio of administered activities. Also a 131I time-activity curve is obtained from planar, Anger-camera, conjugate-view images of the tumor and a known-strength source, both over a series of days. In addition, to correct for any systematic errors in the calculated uptakes, a larger activity of 123I MIBG is administered separately and quantitative Single Photon Emission Computed Tomography (SPECT) is undertaken. A known-strength source also undergoes SPECT to calibrate the tomograms. Correction for Compton scattering is accomplished by the dual-energy-window technique. The subtraction fraction was found to be 0.7 for the 1/2" crystal camera and the mean reduction in tumor counts for seven tumors from Compton correction was 0.76. The normalization factor needed to bring the conjugate-view activities into agreement with the SPECT values ranged from 0.74 to 1.06. A test study on an anthropomorphic phantom indicated that the error in resultant activities might be estimated as +/- 13%. Application of the protocol led to the calculation of real, or potential (when decision was finally made to not administer therapy) radiation absorbed dose to seven tumors in three patients from an administration of about 8 GBq of MIBG. For two metastatic tumors in a 19-year old patient who did not have her primary cancer resected, the calculated radiation absorbed dose was 170 and 180 Gy. For the four metastatic deposits evaluated in two older patients, both of whom had their primary tumor surgically removed, the values ranged from 18 to 31 Gy.

3-Iodobenzylguanidine↗
PubMed1989

Ultrasound detection of differences in density. Explanation of the ureteric jet phenomenon and implications for new ultrasound applications.

Flow of urine from the ureter into the bladder can be encountered during routine sonographic examination of the pelvis. The findings include a stream of hyperechogenic foci spurting into the bladder in real time with the production of a frequency shift during Doppler examination. We have demonstrated that visualization of this phenomenon, at least in part, reflects differences in density and associated compressibility changes between urine in the bladder and in the ureter, and need not be dependent upon flow velocity or other previously hypothesized parameters. The clinical utility of these reproducible and measurable phenomena is explored.

Humans↗
PubMed1986

Iodine-131 treatment of thyroid cancer: absorbed dose calculated from post-therapy scans.

The radiation absorbed dose for nine neck lesions distributed among four thyroid-cancer patients was measured directly from images taken after administration of a treatment dose of 131I. The tumor volume was measured with anterior plus lateral pinhole images by determining magnification and assuming an ellipsoidal shape. Uptake and effective half-life were determined from serial anterior images by use of a calibration curve. Dose lower limits ranged from 2,400 to 29,900 rad. Response to treatment was judged on the basis of one or more follow-up scans at least 8 mo later. All lesions responded to the therapy administration which ranged from 150 to 175 mCi.

Adenocarcinoma↗
PubMed1985

Cysteamine-induced duodenal ulcer is not site-specific: effect of local modulating factors.

In cysteamine-induced duodenal ulcer, an animal model for the clinical disease, lesions are characteristically produced on the anterior and posterior walls of the proximal duodenum. Using this model, we investigated factors that may affect duodenal ulcer localization and intensity. Mobilization of the gastroduodenum by severing its ligaments; circumscribed application of acetic acid to the serosa of the lateral wall of the duodenum; or placement of materials (e.g., gelfoam, parafilm) on the proximal duodenum, each decreased the intensity of anterior-posterior ulcers and resulted in formation of atypical, mostly distal duodenal ulcers. The effect of these manipulations on acid secretion suggests that their influence on the development of duodenal ulcer is not entirely due to modulation of gastric secretion. The data indicate that the localization of induced duodenal ulcer can be shifted distally and is therefore not site specific. This study provides new clues and techniques for the study of the pathogenesis of duodenal ulcer disease.

Acetates↗
PubMed1983

Duodenal ulcerogens cysteamine and propionitrile decrease duodenal neutralization of acid in the rat.

Neutralization of acid was evaluated in rat proximal duodenal segments isolated from biliary and pancreatic secretions. Duodenal ulcerogenic doses of cysteamine produced a significant decrease in acid disposal 0.5-2 hr after treatment. Oral or subcutaneous administration of the duodenal ulcerogen was effective. The potent ulcerogen cysteamine produced a more pronounced decrease than propionitrile (a weak duodenal ulcerogen). The failure of ethanolamine, a nonulcerogenic structural analog of cysteamine to significantly alter acid disposal suggests that the effect is not due to the toxic properties of the duodenal ulcerogen. The results reinforce the concept that the duodenum is able to dispose of significant quantities of acid. The decrease in acid-handling may contribute to duodenal susceptibility to acid after treatment with ulcerogens and possibly reflects pathophysiologic changes early in duodenal ulceration.

Animals↗
PubMedDate not supplied

Divisions of general medicine: ambulatory care activities and responses to cost containment.

To evaluate caring for the poor and uninsured in divisions of general medicine (DGMs), and to document the impact of recent reimbursement changes on division ambulatory care activity, the authors conducted a survey of DGM directors. Questionnaires mailed to directors of 214 divisions or residency programs yielded 120 responses. DGMs staffed, on average, three ambulatory sites, with a median of 17,000 visits per site. Overall, 66% of visits were by poor, underinsured, and uninsured patients. The majority of directors (75%) considered care of the poor a goal of their divisions. The most commonly reported response to the cost containment environment was implementation of revenue-generating measures (66%); 19% reported reductions in care to the poor; and 20% reported increased service to this group. It is concluded that DGMs care for large numbers of poor and uninsured patients and therefore must carefully evaluate the impacts of current policy proposals on their future ambulatory care activities.

Ambulatory Care↗
PubMedDate not supplied

The low incidence of suprascapular nerve injury after primary repair of massive rotator cuff tears.

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.

Adult↗
PubMedDate not supplied

Calculation of pressure gradients from MR velocity data in a laminar flow model.

The MR velocity data obtained in a simple geometry and low Reynolds number are employed to calculate pressure gradients using the known solution of the Navier-Stokes equation. Calculations compare favorably with measured results for the simple model presented. The potential usefulness of noninvasive pressure gradient determination from quantitative analysis of imaging-derived velocity distributions is suggested.

Blood Flow Velocity↗
PubMedDate not supplied

Generalized conservation equation for multicompartmental systems.

A projection operator technique is used to derive an equation for local tissue tracer content Q(t), assuming linear multicompartmental kinetics for tracer utilization. The resulting equation has the form (Equation: see text), where F and Ca(t) denote local blood flow and concentration of tracer, respectively. Tissue complexity is contained within the new parameters lambda, xi(t), and psi(t), where the time-dependent coefficients are expressed as sums of exponentials. Two simple applications are considered: tissue heterogeneity and internal trapping of tracer. The relationship to effective single compartmental analysis, as is used for local cerebral blow flow determination, is evaluated.

Body Fluid Compartments↗
PubMedDate not supplied

Computer-aided diagnosis: detection and characterization of hyperparathyroidism in digital hand radiographs.

An automated method is developed for the detection and staging of skeletal changes due to hyperparathyroidism on digitized hand radiographs. Subperiosteal bony resorption, particularly along the radial margins of the middle and proximal phalanges, is among the earliest manifestations of secondary hyperparathyroidism. In order to quantify the severity of bone resorption in these regions, the computer method analyzes the roughness of the phalangeal margins, as projected on the radiograph. The regions of interest, which contain the phalanges, are obtained from the digitized hand radiographs by an image preprocessor. The radial margin of each phalanx is detected by a model-guided boundary-tracking scheme. The roughness of these boundaries is then quantified by the mean-square variation and the first moment of the power spectrum. A receiver operating characteristic (ROC) study comparing the computer detection of hyperparathyroidism with the diagnosis by three experienced skeletal radiologists was performed by evaluating 84 hand images from 22 patients. Our present computer method can achieve a true-positive rate of 94% and a true-negative rate of 92%. Such a computer-aided diagnosis system may assist radiologists in their assessment of primary and secondary hyperparathyroidism, since it is both accurate and not subject to either intra- or interobserver variations.

Algorithms↗