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Biomedical subjects

J J Carr

Publications and source records attributed to J J Carr.

32 records · Page 2Linked to original sources
PubMed1994

Magnetic resonance contrast agents for neuroimaging. Safety issues.

As physicians, we have an obligation to ensure the safety of our patients as well as to inform them of any potential risks associated with diagnostic procedures. The overall safety profile of the magnetopharmaceuticals with current FDA approval is good with regard to acute toxicity. For gadopentetate dimeglumine, toxicity. For gadopentetate dimeglumine, the agent with the greatest clinical experience, the overriding majority of adverse events consists of transient and relatively minor symptoms and reactions. Clinical trials of the newer agents reflect a similar experience but on a much smaller scale. Continued post-marketing surveillance programs should provide more information in the near future. Severe adverse reactions do occur after the administration of magnetopharmaceuticals. These often idiosyncratic and anaphylactoid reactions may cause permanent injury or death. In the two reported cases to date, the patients had a history of reactive airway disease. The incidence of severe reactions is estimated at 1 in 350,000 to 450,000 for gadopentetate dimeglumine. The rate is considerably lower than that for iodinated contrast agents, both ionic and nonionic. Magnetopharmaceuticals should be considered safe but not innocuous. The small risk must be weighed against the additional diagnostic information that is obtained with magnetopharmaceuticals. Radiologists should be aware of potential complications and have on site equipment and skilled personnel for management should an adverse event occur. The benefits to the patient of reduced morbidity and mortality from improved diagnosis with magnetopharmaceuticals will ensure continued use of current agents as well as development of additional agents.

Adult↗
PubMed1992

Plain and computed radiography for detecting experimentally induced pneumothorax in cadavers: implications for detection in patients.

Pneumothorax was induced in cadavers to determine the effects of patient positioning and imaging modality (conventional screen-film and computed radiography) on radiographic findings. Chest radiography, with cadavers in the supine frontal, erect frontal, and left lateral decubitus positions, was performed at baseline and after injection of incremental quantities of air into the pleural space. Five radiologists independently interpreted each radiograph. The ability of the radiologists to diagnose pneumothorax varied by cadaver position and depended on volume of air. Overall, the left lateral decubitus view was most sensitive (88%) for diagnosis of pneumothorax, followed by the erect (59%) and supine (37%) views. Receiver operating characteristic curves and multiple repeated measures analysis of variance revealed no statistically significant difference between diagnostic proficiency with conventional screen-film radiography and that with computed radiography. The authors conclude that the lateral decubitus view is superior to the erect and supine views for pneumothorax detection and that conventional and computed radiography perform similarly in pneumothorax detection.

Cadaver↗
PubMedDate not supplied

Stereotactic localization of breast lesions: how it works and methods to improve accuracy.

A computer simulation of stereotactic breast biopsy was developed that paralleled the geometric configuration of a currently available breast biopsy system. This model was developed to define and improve the targeting of breast lesions with stereotactic biopsy techniques. Lesions must be clearly identified and accurately targeted on both views for successful localization. Nonvisualization of a lesion may result from overlying tissue or from the geometric configuration of the imaging system. Familiarity with the geometric configuration of the biopsy unit, especially the location of the reference point and center of rotation, facilitates understanding of apparent changes in lesion position (parallax shift). Inaccuracy in lesion targeting on one or both views will manifest predominantly as an error in the calculated z value (depth). The magnitude and direction of this error are largely determined by the direction of the targeting error. Compensatory strategies include use of a long-throw core biopsy gun or directional vacuum-assisted biopsy device and additional sampling along the z axis and should be accompanied by critical evaluation of both pre- and postfire images. Understanding geometric considerations as well as how targeting accuracy affects accuracy in lesion localization should lead to greater success in sampling even challenging breast lesions at stereotactic biopsy.

Biopsy, Needle↗
PubMedDate not supplied

Requirements engineering: the key to designing complex medical systems.

A variety of business systems, clinical work systems, instrumentation systems, information systems, infrastructure systems, and management systems interact to make the modern healthcare facility work. The key to designing for such a system is systems engineering, a skill often little appreciated among clinical engineers. At the heart of systems engineering is requirements engineering and management (REAM), which is defined as "the process of discovering, documenting and managing systems requirements." The principal activities of REAM include eliciting, understanding, negotiating, describing, validating, and managing system requirements. When REAM is done improperly, the resulting system will be satisfactory only if chance intervenes. Well-done REAM is likely to bring the project in on time, under budget, and at full performance.

Biomedical Engineering↗