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Biomedical subjects

Susan Francis

Publications and source records attributed to Susan Francis.

5 recordsLinked to original sources
PubMed2006

Improved echo volumar imaging (EVI) for functional MRI.

Echo volumar imaging (EVI) is a 3D modification of echo-planar imaging (EPI) that allows data from an entire volume to be acquired following a single RF excitation. EVI provides a high rate of volumar data acquisition, which is advantageous for functional MRI (fMRI). However, few studies to date have applied EVI to fMRI, since because of gradient hardware limitations EVI generally has to be used with long sampling times, resulting in high sensitivity to susceptibility-induced distortions. In this study we modified the EVI sequence to improve its suitability for fMRI. The sampling time is reduced by the use of a high gradient-switching frequency, a small number of echoes, and outer volume suppression (OVS); rewind gradients ameliorate Nyquist ghosting; and phase correction via a calibration scan reduces ghosting and distortion. It is shown that the modified EVI sequence allows fMRI data to be acquired with a temporal resolution of 167 ms.

Brain↗
PubMed2005

Malaria vaccines: using models of immunity and functional genomics tools to accelerate the development of vaccines against Plasmodium falciparum.

Naturally acquired immunity and immunity acquired after immunization with attenuated parasites indicate that a vaccine against malaria is feasible. Several obstacles have stymied malaria vaccine development, among them our poor understanding of protective immunity and technical difficulties for studying gene and protein expression in the Plasmodium falciparum parasite. Pregnancy malaria offers a model approach for vaccine development: recent findings have elucidated the basis for disease pathogenesis and protective immunity in this syndrome, and this understanding has focused the effort to identify the optimal antigens for a pregnancy malaria vaccine. In parallel, functional genomics tools are overcoming several of the obstacles for studying protein expression in the malaria parasite, vastly accelerating the pace for antigen discovery. Together, these conceptual and technological advances allow a rational approach to vaccine antigen selection, in which a finite number of antigens are selected from the entire genome by merit of the expression patterns and specific features. These candidate antigens are then subjected to detailed studies according to criteria established by the understanding of pathogenesis and protective immunity, to identify the optimal antigens for inclusion in subunit vaccines.

Animals↗
PubMed2004

Therapy by design: evaluating the UK hospital building program.

A renewed interest in hospital design in the UK, prompted by the Private Finance Initiative, provides an opportunity to consider hospitals as 'therapeutic environments'. Noting that the therapeutic value of hospitals is related to their physical, social and symbolic design, this paper argues that 'expert' knowledges have encouraged the development of hospitals that all-too-rarely provide benign settings for promoting patient recovery and healing. The recent programme of hospital building in the UK, however, has been accompanied by a vigorous debate over what constitutes good hospital design, with four significant ideas emerging: hospitals should be clinically efficient, be integrated within the community, be accessible to consumers and the public, and encourage patient and staff well-being. Suggesting that all four goals demand careful consideration of the real and imagined spatiality of hospital environments, the paper concludes by suggesting ways that health geographers can contribute to debates surrounding PFI hospital design.

Hospital Design and Construction↗
PubMedDate not supplied

Effect of image normalization on carotid plaque classification and the risk of ipsilateral hemispheric ischemic events: results from the asymptomatic carotid stenosis and risk of stroke study.

The aim of this study was to determine the effect of image normalization on plaque classification and the risk of ipsilateral ischemic neurologic events in patients with asymptomatic carotid stenosis. The first 1,115 patients recruited to the Asymptomatic Carotid Stenosis and Risk of Stroke (ACSRS) study with a follow-up of 6 to 84 months (mean 37.1 months) were included in this study. Duplex ultrasonography was used for grading the degree of internal carotid artery stenosis and for plaque characterization (types 1-5), which was performed before and after image normalization. One hundred sixteen ipsilateral ischemic hemispheric events occurred. Image normalization resulted in 60% of plaques being reclassified. Before image normalization, a high event rate was associated with all types of plaque. After image normalization, 109 (94%) of the events occurred in patients with plaque types 1 to 3. For patients with European Carotid Stenosis Trial (ECST) 70 to 99% diameter stenosis (equivalent to North American Symptomatic Carotid Endarterectomy Trial [NASCET] 50-99%) with plaque types 1 to 3, the cumulative stroke rate was 14% at 7 years (2% per year), and for patients with plaque types 4 and 5, the cumulative stroke rate was 0.9% at 7 years (0.14% per year). The results suggest that asymptomatic patients with plaque types 4 and 5 classified as such after image normalization are at low risk irrespective of the degree of stenosis.

Carotid Artery, Internal↗