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Biomedical subjects

R M Lerner

Publications and source records attributed to R M Lerner.

At least 37 records · Page 2Linked to original sources
PubMed1990

"Sonoelasticity" images derived from ultrasound signals in mechanically vibrated tissues.

A method has been developed for detecting and imaging the relative "stiffness," or elasticity of tissues. Externally applied vibration at low frequencies (10-1000 Hz) is used to induce oscillations within soft tissues, and the motion is detected by Doppler ultrasound. The results are displayed in a format resembling conventional Doppler color flow mapping, and are termed "sonoelasticity images." Preliminary experiments indicate that these novel images may be useful for detecting hard tumors in the prostate, liver, breast, and other organs.

Animals↗
PubMed1990

Tissue response to mechanical vibrations for "sonoelasticity imaging".

The goal of "sonoelasticity imaging" is to differentiate between normal soft tissues and hard lesions. This is done by measuring and then displaying the ultrasound Doppler spectrum of regions within tissues which are mechanically forced with low frequency (20-1000 Hz) vibrations. The resolution and sensitivity of the technique ultimately rest on the spatial resolution of ultrasound Doppler detection, the low frequency mechanical properties of tissues, and the vibration response of layered, inhomogeneous regions with hard tumor inclusions and complicated boundary conditions set by the presence of skin, bones and other regions. An initial investigation has measured some tissue stiffness parameters, and applied these in a NASTRAN finite element analysis to simulate a prostate tumor in the pelvic cavity. The measurements show a wide separation between the elastic modulus of tumors and soft tissues such as muscle and prostate. NASTRAN analyses show the ability to delineate regions of different elasticity based on the pattern of vibration amplitudes. The ability to change vibration frequency within the 100-300 Hz band seems particularly helpful in simulations and experiments which visualize small stiff inclusions in tissues. Preliminary results support the postulate that sonoelasticity imaging can provide useful information concerning tissue properties that are not otherwise obtainable.

Computer Simulation↗
PubMed1990

Ultrasound contrast for hepatic tumors using IDE particles.

Iodipimide ethyl ester (IDE) can be formulated as dense spherical particles with narrow diameter distribution. When IDE particles are injected intravenously, the Kupffer cells of the hepatic sinusoids accumulate particles within 10 to 20 minutes, after which the clearance and excretion of IDE takes place. During the uptake phase, the dense particles act as scattering sites, increasing the echogenicity of normal liver tissue. In comparison, tumors and other lesions remain at pre-injection echogenicity, as they lack Kupffer cells and therefore do not retain particles. This report provides initial studies of contrast enhancement in rabbit livers with implanted VX2 tumors, scanned in vivo and evaluated ex vivo using pulse-echo techniques. The distribution of particles within hepatic lobules may explain why the observed echogenicity is greater than that predicted by single-particle backscatter theory. Directions for future improvements are discussed.

Animals↗
PubMed1990

Color Doppler US in the evaluation of acute scrotal disease.

Twenty-seven patients presented with painful acute scrotal swelling. After a clinical impression was established, all patients underwent diagnostic imaging with color Doppler ultrasound (US). Seven patients underwent surgical exploration for testicular torsion diagnosed with color Doppler US (100% operative confirmation), one underwent radical orchiectomy for treatment of seminoma, and one underwent orchidopexy for treatment of a freely mobile testis. Eighteen patients were treated for nonoperable conditions. Diagnoses made with color Doppler US correlated with final clinical diagnoses in all patients. In 10 of 27 patients (38%), the diagnosis was established at color Doppler US. Until now, nuclear scanning has had a paramount role in the evaluation of equivocal cases of acute scrotal disease. Results show that color Doppler US helps accurately correlate anatomy and perfusion in real time and may prove to be the definitive imaging technique for the diagnostic evaluation of acute scrotal pain or swelling.

Acute Disease↗
PubMed1989

Objective and subjective attractiveness and early adolescent adjustment.

Using data from the Pennsylvania Early Adolescent Transitions Study (PEATS), this study assessed how objective physical attractiveness (PA), indexed by appraisals from others, and subjective PA, indexed by self-appraisals, relate to each other and, in turn, to early adolescent adjustment (indexed by self-esteem and anxiety). Findings indicated a low relationship between objective and subjective PA. Only subjective PA was associated with adjustment.

Adaptation, Psychological↗
PubMed1989

Penile abscess involving the corpus cavernosum: a case report.

A patient with a penile abscess containing mixed colonies of bacteria is presented. Ultrasound scan confirmed the physical examination findings of involvement of the corpus cavernosum. After incision and drainage the patient has normal erectile function.

Abscess↗
PubMed1989

Conceptual issues in studying continuity and discontinuity in personality development across life.

In this article, we argue that the continuity-discontinuity of personality development is not just an empirical issue, but is also a metatheoretical and theoretical issue. Stances taken in regard to one of three metatheories (or models)--the organismic, the mechanistic, and the developmental contextual--determine theoretical ideas about (a) the units of analysis thought to be relevant to personality development; (b) the processes believed to govern these units; and (c) whether changes in these units are continuous or discontinuous. Theories associated with the models also differ in regard to whether they describe and/or explain intra-individual personality changes as quantitatively or qualitatively continuous or discontinuous. Developmental contextual theories seek to identify the organismic and contextual conditions under which any instance of continuity-discontinuity occurs. These conditions involve both nomothetic and idiographic processes. Organism-context relations must be studied longitudinally in order to understand how these processes function across life.

Biological Evolution↗
PubMed1988

Wave space interpretation of scattered ultrasound.

Wave space is described nonmathematically for design and interpretation of ultrasound scattering experiments. By considering ultrasound scattering from a variety of targets and geometries, the wave space approach is shown to describe target characteristics in terms of spatial frequencies and their amplitudes. Experimental limitations for determining effective spacing of scattering structures and scattering medium anisotropy are discussed.

Biophysical Phenomena↗
PubMed1988

In-vivo measurements of ultrasound attenuation in normal or diseased liver.

Ultrasonic attenuation coefficients of liver have been derived from echoes received by a modified commercial B-scan imaging instrument. Values have been measured from selected regions within liver scans of 59 individuals, of which 15 cases were presumed normal (based on medical histories), and the remainder were involved with diffuse liver disease such as alcoholic cirrhosis, chemotherapy toxicity, chronic hepatitis, and liver metastases. Medical histories on most individuals include the results of serum liver function enzymes, conventional B-scan examinations, and exposure to drugs and alcohol. The results of CT abdominal scans (N = 13) and/or liver biopsy (N = 12) were also available. The results show that normal attenuation values for human liver are 0.054 +/- 0.009 Np/cm-MHz (0.47 dB/cm-MHz) with a frequency dependence of fn, where n = 1.05 +/- 0.25, in agreement with in vitro studies of mammalian liver. In diffuse liver disease, no relationship was found between the attenuation coefficient and the results of CT or conventional ultrasonic examination. A trend towards higher attenuation with increased fibrosis and fat, as graded from liver biopsies, was noted, but the results were generally not statistically significant. However, a significant correlation was found between high values of attenuation and abnormal liver function tests. High attenuation is also found with ingestion of alcohol, chemotherapeutic agents, and steroids, all of which may affect liver composition.

Adolescent↗
PubMed1988

Stage IB cervical carcinoma: comparison of clinical, MR, and pathologic staging.

In patients with stage IB cervical carcinoma (carcinoma confined to the cervix), accurate staging is essential in order to determine the best treatment strategy--that is, whether to use surgery alone or surgery in combination with pre- or postsurgical radiation therapy. Currently, decisions regarding the management of patients are made on the basis of clinical staging that has an error rate of 34-39% (when surgical staging is used as the standard). To investigate the value of MR in staging patients with IB cervical cancer, we performed prospective MR examinations in 27 patients who had cervical carcinoma. Of these, 10 were clinically staged as having IB cervical carcinoma and underwent radical hysterectomy, providing specimens for pathologic correlation. In six of these 10 patients, the extent of disease had been underestimated during clinical examination under anesthesia. These six patients would have received radiation therapy before surgery had the MR information been used at the treatment-planning stage. MR imaging correlated better with surgical pathology than did clinical examination under anesthesia in determining the location and extent of tumor. MR imaging should be used in conjunction with clinical staging to determine appropriate therapy in patients with stage IB cervical carcinoma.

Adult↗
PubMed1987

CT staging of early rectal carcinoma.

Of 43 rectal carcinomas, initially presumed to be modified Dukes' stage A or B-1, 42 were examined with computed tomography (CT) prior to endocavitary treatment or surgery in 40 cases. The CT correctly showed 28 patients to have early stages and incorrectly showed 2 to have perirectal extension. Three patients had anal neoplasms. The remaining 10 patients had disease stage B-2 or higher and CT was not good for staging them. A CT scan can fairly accurately stage rectal carcinomas stage A and B-1 grouped together, and is doing better in predicting the prognosis than digital palpation when histologic sections show well or moderately well-differentiated adenocarcinoma of the rectum.

Adenocarcinoma↗
PubMed1987

A particulate contrast agent with potential for ultrasound imaging of liver.

Ultrasonic backscatter and attenuation coefficients of a medium can be increased by the addition of solid, micron sized inhomogeneities. A potentially useful agent for ultrasonic contrast of liver images has been identified. Iodipamide ethyl ester (IDE) particles can be produced in the form of dense, relatively incompressible solids with high impedance mismatch to water. The chemical, biomechanical, and pharmacological properties of the small, uniform diameter IDE particles permit safe intravenous injection followed by rapid accumulation by reticuloendothelial (RE) cells of the liver and spleen, and later elimination from these organs. Since the particles are phagocytized by RE cells, present in normal liver but not in tumors and many lesions, the selective enhancement of ultrasonic backscatter should improve detectability of lesions which are hypo- or iso-echoic compared to surrounding tissue. The mechanisms of particle-ultrasound interaction may be described by relative motion attenuation, and scattering from a cloud of dense, incompressible spheres for the case of IDE particles in agar. Thus, values of attenuation and backscatter can be controlled by choice of ultrasound frequency and particle concentration and size. When the particles are accumulated in rat livers, additional mechanisms induce attenuation and backscatter in excess of that predicted by IDE in agar. This preliminary work demonstrates that solid, biocompatible particles may be useful as an ultrasonic contrast agent.

Animals↗
PubMed1986

Testicular abscess: diagnosis by ultrasonography.

We reviewed 8 cases of surgically proved testicular abscess with emphasis upon the ultrasonographic findings. The images were correlated with testicular anatomy and the pathological findings of abscess formation. In 3 of 8 patients undergoing serial high resolution ultrasound examinations a consistent pattern of testicular abscess was present 1 to 7 weeks preoperatively. In the remaining 5 patients preoperative ultrasound documented the presence of abscess. Recognition of the ultrasonographic appearance of testicular abscess should permit expedient surgical intervention.

Abscess↗
PubMed1986

Distal ureteral calculi: diagnosis by transrectal sonography.

Eight patients were studied by both transrectal sonography and excretory urography for the presence of distal ureteral calculi. The sonographic diagnosis was correct in 5 of 5 true positives and 3 of 3 true negatives. Urography was correct in 4 of 5 true positives and 2 of 3 true negatives. None of the sonograms and two of the urograms were considered equivocal. Transrectal sonography appears to be a useful adjunct for the diagnosis of distal ureteral calculi when excretory urography is equivocal or contraindicated.

Adult↗
PubMed1985

Temperament and elementary school children's actual and rated academic performance: a test of a 'goodness-of-fit' model.

To test a goodness-of-fit model of temperament, 194 Pennsylvania fourth-grade students were studied. It was predicted that children whose temperament fitted or exceeded demands or expectations of their teachers would show more positive functioning than children whose temperament fell below expectations. Children responded to the Dimensions of Temperament Survey (DOTS), which assesses 5 temperamental attributes. Teachers specified demands/expectations for their students for each of the DOTS attributes and rated students' academic ability and adjustment. Objective measures of academic achievement were also obtained. Results indicated that for 2 of the 3 temperament attributes for which directional predictions were made some support was obtained for the model.

Achievement↗
PubMed1985

Contracted gallbladder: a finding in hepatic dysfunction.

A review of ultrasound (US) examinations of 35 patients with acute hepatitis revealed 6 patients who had contracted gallbladders despite adequate fasting prior to the examination. After the acute phase of their hepatitis had resolved, four patients had normal gallbladders on US. One patient who did not recover was found at autopsy to have a normal but contracted gallbladder. It is suggested that acute hepatic dysfunction may decrease the flow of bile into the gallbladder, resulting in a gallbladder that is transiently contracted or is not visualized on US.

Acute Disease↗