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Biomedical subjects

R M Lerner

Publications and source records attributed to R M Lerner.

At least 19 recordsLinked to original sources
PubMed1992

Temperament and adjustment in young adulthood: a 15-year longitudinal analysis.

The relationship between easy/difficult temperament and adjustment from middle adolescence to young adulthood was examined. Cluster analysis revealed four groups of individuals via composite temperament scores over three points of measurement. Multivariate analyses indicated that extremely difficult temperament was associated with poorer psychosocial functioning in childhood and young adulthood.

Adaptation, Psychological↗
PubMed1992

Sonographic measurement of diaphragmatic motion after coronary artery bypass surgery.

Forty-eight patients were prospectively evaluated following coronary artery bypass grafting (CABG) in order to determine values for diaphragmatic mobility by sonography, to compare diaphragmatic motion to chest x-ray findings, to relate diaphragmatic motion to pulmonary function tests, and to determine whether use of the left internal mammary artery (LIMA), aortic cross-clamp time, or other clinical variables were predictive of diaphragmatic dysfunction. Mean left diaphragmatic motion was 2.8 +/- 1.1 cm (range, 1.0 to 5.7 cm), mean right diaphragmatic motion was 3.9 +/- 1.1 cm (range, 1.8 to 6.4 cm), and ratio of left to right motion was 0.74 +/- 0.27 (range, 0.19 to 1.4). Forty-one patients had normally positioned diaphragms on the chest x-ray film; four of these had poor mobility by ultrasonography (< 1.6 cm). Of the seven elevated left hemidiaphragms on chest x-ray films, three had an excursion of 1.6 cm or more by ultrasonography. The mean FVC for all patients was 59 +/- 13 percent of predicted. There was no relationship between diaphragmatic mobility and FVC or negative inspiratory pressure. The diaphragmatic motion in 36 patients having LIMA grafting was similar to those without (2.7 +/- 1.2 cm [n = 36] vs 2.8 +/- 0.8 cm [n = 12], respectively). Aortic cross-clamp time and respiratory symptoms also did not correlate with diaphragmatic mobility. Sonography can be used in the evaluation of diaphragmatic motion after CABG and may be more accurate in detecting a poorly mobile diaphragm than is the chest x-ray film.

Coronary Artery Bypass↗
PubMed1992

Sonoelasticity of organs: shear waves ring a bell.

Sonoelasticity is the use of ultrasonography to visualize, in real time, the hardness of stiffness of tissues and organs by depicting the tissue's motion in response to an applied vibration source. The applied vibration source is usually of low amplitude and low frequency (less than 0.1 mm displacement and less than 2000 Hz). Under these conditions, the natural vibration response of tissues and whole organs is revealed as a standing wave pattern determined by the low-frequency elastic constants of the tissues and their boundary conditions, factors that are not related to the ultrasonic echogenicity. As a result, hard or dense isoechoic tumors that are undetectable by conventional ultrasonography often can be visualized in sonoelasticity imaging by virtue of their altered vibration response. In this report, we demonstrate the appearance of organs such as the breast, liver, and kidney during real-time, in vivo sonoelasticity imaging. The results show that the shape and location of vibration patterns are dependent on the tissues and vibration frequencies; thus, information about the basic elastic properties of tissues should be obtainable.

Breast↗
PubMed1991

Color Doppler ultrasound compared to a radionuclide scanning of spermatic cord torsion in a canine model.

High resolution color doppler ultrasound can simultaneously display blood flow superimposed on detailed gray scale anatomic images. Using a single-blind study design, nine adult male dogs underwent intravaginal spermatic cord torsion and subsequent evaluation with technetium 99M-pertechnetate radionuclide, and color doppler ultrasound imaging techniques. Torsions of 90 to 720 degrees were created surgically, followed by examination with each modality at one hour (four animals), and four hours (five animals) following the procedure. Testicular torsion was diagnosed if perfusion was absent or markedly diminished on color doppler imaging or radionuclide scan. In all cases of 360 degrees or greater, torsion was diagnosed by either modality at both one and four hour time delays. If observers did not diagnose torsion, they were asked to assess the relative testicular perfusion. Color doppler ultrasound and radionuclide scanning were without error in correctly detecting a relative decrease in perfusion in each of these instances. Furthermore, color doppler imaging with spectral analysis was able to detect an enhancement of the diastolic component of the arterial signal at 180 degrees of torsion. This spectral pattern coupled with a relative decrease in blood flow allowed presumptive diagnosis at one hour of partial torsion that was subsequently apparent as absent perfusion only after 4 hours on radionuclide and repeat color doppler ultrasound. Color doppler ultrasound proved to be superior to radionuclide scanning in detecting diminished perfusion in this experiment. The detailed information provided by spectral and anatomic display with color doppler ultrasound recommends it for the evaluation of acute scrotal pathology of uncertain etiology.

Animals↗
PubMed1991

Sonoelasticity imaging: results in in vitro tissue specimens.

The authors present a method for imaging tissue stiffness (sonoelasticity) that has been developed and tested in a laboratory setting by using in vitro canine and human prostate glands. A low-frequency acoustic source was used to induce vibration in tissue under examination, and a color Doppler ultrasound (US) instrument was modified to detect vibration amplitude. The resulting image is a color "map" of tissue vibration superimposed on conventional gray-scale US images. Stiffer tissues vibrated less in response to audible sound, regardless of echogenicity. Normal human and canine prostate glands demonstrated a uniform vibration pattern. Four of four human prostatic adenocarcinomas and two stiff inclusions injected into canine prostate glands demonstrated a lack of vibration in comparison with normal surrounding tissue. The authors conclude that while further study is necessary, sonoelasticity imaging may enhance the detection of neoplasms by enabling their identification solely on the basis of stiffness.

Adenocarcinoma↗
PubMed1991

Testicular imaging.

Clinicians have relied on radionuclide scanning for evaluating acute scrotal pain and on ultrasonography for chronic scrotal pain and anatomic lesions (testicular and paratesticular structures). This review reinforces the utility of these established imaging techniques and also introduces color Doppler ultrasonography as an integral component in the advancement of testicular imaging, particularly in effective and timely diagnosis of spermatic cord torsion. The expanding capability of MR imaging for scrotal disorders is presented.

Color↗
PubMed1990

Relations among early adolescent temperament, parent and peer demands, and adjustment: a test of the goodness of fit model.

This study assessed whether the goodness of fit--between early adolescents temperaments and their parents and peers demands, or "ethnotheories", regarding temperament--was more related to adjustment than were acontextual measures of temperament alone. Data from the Pennsylvania Early Adolescent Transitions Study, a short-term longitudinal investigation of 153 adolescents from the beginning of sixth grade to the end of seventh grade, were used. Temperament was indexed by the nine attributes measured by the Revised Dimension of Temperament Survey, and the measures of demands regarding temperament were derived from different versions of this instrument. Adjustment was indexed by teacher ratings of academic and social competence and by parent ratings of problem behaviors. At the end of Grade 6 and the beginning of Grade 7, the number of significant relations between the adjustment measures and the fit scores tended to be greater than the number of significant relations between adjustment and temperament, measured alone. Moreover, groups formed on the basis of high vs. low temperament fit showed differential adjustment scores: adolescents in the low fit group in regard to both peer- and parent-demands received lower teacher ratings of scholastic competence, and higher parent ratings for conduct and school problems, than did the adolescents in the high fit group.

Child↗
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↗