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Biomedical subjects

B J Manaster

Publications and source records attributed to B J Manaster.

89 records · Page 5Linked to original sources
PubMed1987

Technetium-99m imaging of bone trauma: reduced sensitivity caused by hydrocortisone in rabbits.

This study evaluates the effect of hydrocortisone on the sensitivity of 99mTc-scintigraphy for the detection of bone trauma in three groups of rabbits: a control group that received no hydrocortisone, a low-dose group that received 0.8 mg/kg/day, and a high-dose group that received 20 mg/kg/day. Scintigrams of the tibial diaphyses were obtained at 48 hr, 1 week, 2 weeks, and 3 weeks after surgical creation of a simulated fracture (a 1.5-mm hole in the cortex). The mean sensitivity for detecting fractures in control animals was 95% at 48 hr and 100% at all other times. Mean sensitivity for rabbits given the high dose of hydrocortisone was 41% at 48 hr. Mean sensitivity for the low-dose group was 75% at 48 hr, but this was not significantly different from the control group. Sensitivity in both groups treated with hydrocortisone improved with time. At 3 weeks, the mean was 93% in the low-dose group and 83% in the high-dose group. These data suggest that 99mTc scintigraphy may be less sensitive in detecting bone trauma in patients on glucocorticoid therapy than in patients in the general population.

Animals↗
PubMed1986

Negative bone scans of joints after aspiration or arthrography: experimental studies.

It has long been suspected anecdotally that needle aspiration or contrast arthrogram before bone scan may cause a false-positive bone scan. This dictum often directs the sequence of events in the clinical workup of joint disease, yet data to support or refute this are lacking. This study was undertaken to generate such data. Fifty-six joints in mature dogs were examined, including hips, knees, elbows, and shoulders. The joints were examined in pairs; one joint was injected with Conray 60 for an arthrogram, and the contralateral joint was injected with an equal volume of normal saline to simulate a joint aspiration. Confirmation of needle placement and injection into the joints was made with fluoroscopic and digital subtraction imaging. Numbers of attempts required for aspiration and quantity of contrast material extravasated were noted for each joint. Baseline 99mTc-HDP or 99mTc-MDP bone scans were done before the experimental joint aspirations, with follow-up scans at 24 and 96 hr. The scans showed no significant change from baseline after either needle aspiration or arthrogram. When the diagnostic workup suggests the need for such a procedure, it should be performed. In contradiction to popular belief, joint aspiration and/or arthrogram did not affect a subsequent bone scan.

Animals↗
PubMed1986

Digital wrist arthrography: precision in determining the site of radiocarpal-midcarpal communication.

Wrist arthrography is used for precise determination of posttraumatic interosseous ligament tears. Digital subtraction arthrography adds to the precision in diagnosis of the site of radiocarpal-midcarpal communication. Using the technique for digital subtraction wrist arthrography outlined in this paper, the classic scapho-lunate and lunate-triquetral perforations were delineated. Scaphotrapezium and triquetral-hamate interosseous ligament perforations were also delineated. The added diagnostic precision of digital subtraction at the first injection was useful in planning the correct surgical procedure.

Carpal Bones↗
PubMed1983

Radiology of medullary chondrosarcoma: preoperative treatment planning.

We evaluated the radiologic studies of 30 medullary chondrosarcomas with respect to their accuracy in diagnosis and surgical staging. There were 30 sets of plain radiographs, 14 conventional tomograms, 26 radionuclide bone scans, 19 arteriograms, and 15 computed tomograms (CT). Plain radiographs provided most of the diagnostic information although many tumours looked benign. CT provided the most complete anatomic staging, including intra- and extraosseous tumor, and neurovascular involvement. However, it was difficult to be sure about subtle soft tissue invasion. Arteriography remained useful for evaluating major vessel involvement or cortical penetration when CT and conventional tomography were equivocal. Scintigrams disclosed increased uptake, usually corresponding to the true tumor extent; "extended uptake" beyond the tumor was uncommon. Conventional tomography has been largely replaced by CT, but was occasionally useful when the tumor was near the end of a bone.

Adult↗
PubMed1983

CT diagnosis of thoracic pedicle aplasia.

A rare case of congenital absence of a pedicle in the thoracic spine is presented. The merit of prompt confirmation of the diagnosis by computed tomography is discussed.

Female↗
PubMed1983

Scintigraphy of benign exostoses and exostotic chondrosarcomas.

Technetium-99m diphosphonate scintigraphy of 11 benign exostoses and nine exostotic chondrosarcomas was correlated with pathologic macrosections of the resected tumors. Increased uptake in benign exostoses occurred in areas of enchondral ossification, and uptake in chondrosarcomas occurred in areas where ossification, osteoblastic activity, and hyperemia were found. Uptake was not related to amorphous cartilage calcification. Radiopharmaceutical uptake, therefore, correlated with areas of ossification visible radiographically, and large masses of nonossifying cartilage were not detected. Radionuclide bone imaging did not contribute to the preoperative anatomic evaluation of these tumors, and it did not always distinguish benign from malignant lesions.

Adolescent↗
PubMed1982

Development of a mathematical model of the cervical spinal canal and its use in detecting early pathologic changes.

Detection of subtle osseous changes on plain film roentgenograms of the cervical spine is essential in expediting the evaluation of suspected intraspinal tumors. It is our experience that the earliest osseous changes in such cases involve thinning or erosion of the adjacent pedicles and/or lamina and a subsequent increase in the oblique diameter of the cervical spinal canal. A statistical model is established which accurately describes the normal cervical vertebral column in terms of its spinal canal size (sagittal and oblique diameters) as well as pedicle and lamina thickness. Data was obtained from a series of 86 normal exams. Six surgically proven cases of cervical intraspinal tumors were analyzed using this model. Variations from expected normal values reveal statistically significant osseous changes involving thinning of the lamina and increased oblique diameter of the spinal canal, while the sagittal diameter of the canal remains normal. Because of these findings we feel that oblique cervical spine films should be included in the initial evaluation of neural canal tumors.

Adult↗
PubMed1982

Tumoral calcinosis: serial images to monitor successful dietary therapy.

Tumoral calcinosis involves formation of periarticular calcified soft tissue masses. Experimental evidence suggests a metabolic etiology with dietary restriction of calcium and phosphorus as beneficial therapy. We prospectively monitored serum levels of calcium, phosphorous, alkaline phosphatase, and erythrocyte sedimentation rate (ESR) while successfully treating a patient with tumoral calcinosis. The values were compared with changes on serial radiographic and radionuclide bone and gallium images. Our work suggests using serial serum phosphate levels and the ESR as the most sensitive indications of progress in dietary treatment of tumoral calcinosis.

Alkaline Phosphatase↗
PubMed1982

Isolated internal iliac artery aneurysms.

A case of bilateral isolated internal iliac artery aneurysms in a patient with sciatic symptoms is presented. Iliac artery aneurysms are rare in the absence of aortic aneurysms; they are usually atherosclerotic in nature and present most commonly with gastrointestinal, genitourinary, or neurologic symptoms.

Aged↗
PubMed1982

Radionuclide bone scanning of medullary chondrosarcoma.

Technetium-99m methylene diphosphonate bone scans of 18 medullary chondrosarcomas of bone were correlated with pathologic macrosections of the resected tumors. There was increased scan uptake by all 18 tumors, and the uptake in 15 scans corresponded accurately to the anatomic extent of the tumors. Only three scans displayed increased uptake beyond the true tumor margins; thus, the "extended pattern of uptake" beyond the true tumor extent is much less common in medullary chondrosarcomas than in many other primary bone tumors. Therefore, increased uptake beyond the apparent radiographic margin of the tumor suggests possible occult tumor spread. Pathologically, there was intense reactive new bone formation and hyperemia around the periphery of all 18 tumors, and there were foci of enchondral ossification, hyperemia, or calcification within the tumor itself in nearly every tumor. Three scans displayed less uptake in the center of the tumors than around their peripheries. One of these tumors was necrotic in the center, but the other two were pathologically no different from tumors that displayed homogeneous uptake on the scan.

Bone Neoplasms↗
PubMed1979

Locomotor adaptations within the Cercopithecus Genus: a multivariate approach.

Multivariate analysis as a technique for investigating locomotor differentiation among primates has proven its power and usefulness in many studies on various skeletal dimensions. In these analyses primate genera were distributed and sometimes clustered in a manner that was interpretable based on current knowledge of gross locomotor differences. In an effort to advance our understanding of arboreality and terrestriality in primates, the present research involves a careful look for the most subtle morphological differences in locomotor behavior. It is believed that by looking at such subtle shape differences an understanding of what it means morphologically for a primate to be either more or less arboreal may be achieved. The species within the primate genus Cercopithecus were analyzed. This genus includes species which may be placed along a habitat (ground-living to tree-dwelling) or activity spectrum. The different habitats or activity patterns clearly require slight variations in patterns of movement, which in turn may require subtle structural adaptations. Multivariate analyses of 67 postcranial variables on seven species within the genus allowed detection of slight degrees of morphological variation. However, when morphological differences are small, size variance among specimens may take on an inflated importance. A substantial amount of work was devoted to finding the least biased method of removing size variance from the variables while incorporating a discrete size variable into the study. Using these transformed skeletal variables, interspecific groupings were discovered. Much of this infrastructure is then related to differing locomotor behavior and provides an insight into the fine structure of primate locomotor adaptation in an arboreal habitat.

Animals↗
PubMed1975

Techniques for estimating allometric equations.

Morphologists have long been aware that differential size relationships of variables can be fo great value when studying shape. Allometric patterns have been the basis of many interpretations of adaptations, biomechanisms, and taxonomies. It is of importance that the parameters of the allometric equation be as accurate estimates as possible since they are so commonly used in such interpretations. Since the error term may come into the allometric relation either exponentially or additively, there are at least two methods of estimating the parameters of the allometric equation. That most commonly used assumes exponentiality of the error term, and operates by forming a linear function by a logarithmic transformation and then solving by the method of ordinary least squares. On the other hand, if the rrror term comes into the equation in an additive way, a nonlinear method may be used, searching the parameter space for those parameters which minimize the sum of squared residuals. Study of data on body weight and metabolism in birds explores the issues involved in discriminating between the two models by working through a specific example and shows that these two methods of estimation can yield highly different results. Not only minimizing the sum of squared residuals, but also the distribution and randomness of the residuals must be considered in determing which model more precisely estimates the parameters. In general there is no a priori way to tell which model will be best. Given the importance often attached to the parameter estimates, it may be well worth considerable effort to find which method of solution is appropriate for a given set of data.

Anatomy↗
PubMedDate not supplied

MR angiography for preoperative evaluation of vascularized fibular grafts.

PURPOSE: Two magnetic resonance (MR) angiography pulse sequences, two-dimensional (2D) time of flight (TOF) and multislab three-dimensional (3D) TOF, were compared for ease of application and capability of depicting the arterial trifurcation in candidates for vascularized fibular grafts. PATIENTS AND METHODS: Both 2D TOF and multislab 3D TOF MR angiography procedures were performed to image the lower legs of 15 healthy volunteers and six patients. Three radiologists evaluated each study for the number of trifurcation vessels depicted at the knee and at the ankle, the corresponding degree of confidence, and the presence of anatomic variants. RESULTS: All trifurcation vessels were identified at the level of the knee with a high degree of confidence. Usually two vessels could be identified at the ankle with a slightly lower degree of confidence. A higher number of vessels were identified at the ankle with the 2D TOF technique than with the 3D TOF technique. A number of anatomic variants were identified. Anatomy of all six patients was identified correctly and confirmed at surgery. CONCLUSION: Both 2D TOF and multislab 3D TOF are useful techniques to define the arterial anatomy of the lower leg and have proved valuable in preoperative planning for vascularized grafts. Vessel visualization at the level of the ankle was superior with the 2D TOF technique.

Fibula↗