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Biomedical subjects

M Yam

Publications and source records attributed to M Yam.

10 recordsLinked to original sources
PubMed2004

Fusion of contrast-enhanced breast MR and mammographic imaging data.

Increasing use is being made of Gd-DTPA contrast-enhanced MRI (CE-MRI) for breast cancer assessment since it provides three-dimensional (3D) functional information via pharmacokinetic interaction between contrast agent and tumour vascularity, and because it is applicable to women of all ages as well as patients with post-operative scarring. CE-MRI is complementary to conventional X-ray mammography, since it is a relatively low-resolution functional counterpart of a comparatively high-resolution 2D structural representation. However, despite the additional information provided by MRI, mammography is still an extremely important diagnostic imaging modality, particularly for several common conditions such as ductal carcinoma in situ (DCIS) where it has been shown that there is a strong correlation between microcalcification clusters and malignancy. Pathological indicators such as calcifications and fine spiculations are not visible in CE-MRI and therefore there is clinical and diagnostic value in fusing the high-resolution structural information available from mammography with the functional data acquired from MRI. This article is a clinical overview of the results of a technique to transform the coordinates of regions of interest (ROIs) from the 2D mammograms to the spatial reference frame of the contrast-enhanced MRI volume. An evaluation of the fusion framework is demonstrated with a series of clinical cases and a total of 14 patient examples.

Breast Neoplasms↗
PubMed2001

A mammographic dilemma: calcification or haemosiderin as a cause of opacities? Validation of a new digital diagnostic tool.

Core biopsies of an area of microcalcification demonstrated large collections of macrophages containing haemosiderin, with evidence of minimal microcalcification on H&E staining. Algorithms were developed that were capable of differentiating with high accuracy those signs due to calcification, using quantitative measurements such as the apparent volume composition of calcium. Using the linear attenuation coefficients of calcification and assuming an ellipsoid model for the 3-dimensional shape of calcification, we computed the relative calcification volume for each region of interest. The difference in the linear attenuation coefficients of iron and calcification allowed the two to be differentiated on a mammogram based on this measure of relative calcification volume.

Breast↗
PubMed2001

Three-dimensional reconstruction of microcalcification clusters from two mammographic views.

Classification of benign/malignant microcalcification clusters is a major diagnostic challenge for radiologists. Clinical studies have revealed that the shape of the cluster, and the spatial distribution of individual microcalcifications within it, are important indicators of its malignancy. However, mammographic images of clustered microcalcifications confound their three-dimensional (3-D) distribution with image projection and breast compression. This paper presents a novel model-based method for reconstructing microcalcification clusters in 3-D from two mammographic views (cranio-caudal and medio-lateral oblique--"shoulder to the opposite hip" or lateral-medio). We develop a 3-D breast representation and a parameterised breast compression model which constraints geometrically the possible 3-D positions of a calcification in a two-dimensional image. Corresponding calcifications in the two views are matched using an estimate of the calcification volume. Both the geometric constraint and the matching criterion are utilized in the final reconstruction step to build the 3-D reconstructed clusters. Validation experiments are described using 30 clusters to verify the individual steps of the model, and results consistent with known ground truth are obtained. Some of the approximations in the model and future work are discussed in the concluding section.

Algorithms↗
PubMed2000

Seen but not heard: battered women's perceptions of the ED experience.

INTRODUCTION: A plethora of studies describe helping professionals' responses to and actions directed toward battered women in the emergency department. However, research that yields data regarding the clients' perceptions about their actual experiences in the ED setting is sorely needed. The aim of this study was to describe battered women's perceptions of their ED experience. METHOD: A qualitative design, namely a phenomenologic approach, was used for this inquiry to enable the women to express themselves in their own voices. Informants were recruited from shelters for battered women. Women who had sought help for abuse-related injuries at a hospital emergency department within the past 12 months were asked to participate. Methods used to collect data were in-depth, individual, audiotaped interviews and demographic data sheets. Data analysis was conducted using Colaizzi's (1978) procedural steps. RESULTS: Several categories emerged as being descriptive of the women's perceptions of their ED experience. Themes identified included the women's feelings during the visit, such as fear of their partner, concern for children, and loneliness; the women's belief that the ED staff do not understand abuse; satisfaction with treatment of physical injuries but dissatisfaction with how the issue of abuse is managed; the difficulty of disclosing the abuse because of fear, embarrassment, and a lack of resources; and a request that health care professionals display compassion, provide referrals, and offer options. DISCUSSION: The women's narratives explicate their feelings during the ED visit and sensitize nurses to their experience. The reports of dissatisfaction with the care they received in the emergency department add to the validity of findings from previous studies that have documented similar results and point to the need to examine and reshape the delivery of care to abused women in the emergency department.

Adult↗
PubMed1995

Wife abuse: strategies for a therapeutic response.

An alarming number of women seek help for abuse from the health care establishment. Yet research shows that all too often, professionals fail to identify abuse and are nontherapeutic. This paper provides theoretical and research evidence to explore the factors that account for the less than helpful response of nurses toward wife-abuse victims. A feminist lens is used to explore strategies that can enable nurses to deal effectively with this health care dilemma.

Female↗
PubMed1992

Domestic violence. The pregnant battered women.

Nurses need to understand the theoretic debates that attempt to explain why men batter women. Nurses can participate more effectively in preventing and reducing the incidence of physical violence directed against women in intimate relationships. A raised feminist consciousness will expand the nurse's repertoire of interventions to assist in the identification and treatment of victims.

Female↗
PubMed1989

Work performance by persons with multiple sclerosis: conditions that impede or enable the performance of work.

This study queried 508 persons diagnosed with multiple sclerosis (MS) regarding what conditions made performing their work or tasks 'difficult' and 'easier'. The subjects represented four groups: employed outside the home, homemakers, unemployed, and retired. Their written responses were content analysed. Conditions reported to impede the performance of work and tasks were related to three categories: physical restrictions, person-environment interaction, and MS-related symptoms. Conditions reported to enhance the performance of work and tasks were related to five categories: assistive devices, human support, personal attributes, health promotion behaviors, and person-environment adjustment. Study findings provide useful information for families, health service providers and employers of persons with MS in assisting them enhance their ability to perform work or tasks.

Activities of Daily Living↗