1,331 research outputs found
Imaging of the Paranasal Sinuses
MRI in most instances, can better distinguish between soft tissues when compared with CT. The distinction of soft tissues becomes most clinically relevant when evaluating for possible sinonasal tumors and when inspecting for extension of tumor or inflammation into the orbit or intracranial spaces. It is in these areas that MRI has found its major application in sinus imaging. This unit presents MRI techniques for imaging the sinuses with and without contrast enhancement. The parameters given in this unit are derived from experience at 1.5 T and may need to be slightly altered depending on the field strength and the equipment manufacturer.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145394/1/cpmia0706.pd
Safe MR scanning of patients with metallic middle ear implants
Objective: To determine the MR scanning risk to patients with otologic implants. Design: We used a repeated-measures study with an additional control measure to assess two aspects of risk; i) movement of the device in the magnetic field, and ii) absorption of energy leading to local heating. We used an ex vivo test method that met with international standards. We measured the effects in a Philips Intera Achieva 3 Tesla MR scanner using a Sense Head 8 channel RF coil. Setting: University based magnetic resonance research facility Main outcome measures: Heating or displacement of the stapedectomy pistons Results: No evidence of displacement or heating was found. Conclusion: Complying with the ex vivo standard testing protocols, the Schuknecht and McGee wire pistons, (device product numbers 140106 and 140108 respectively) were found to be safe in a 3 T MR scanner. These conclusions can be extrapolated to the in vivo case
Screening Forms for Patients for MR Procedures and Individuals for the MR Environment
This appendix presents the screening forms that are to be filled by the patient prior to being scanned. Completion of these screening forms is also required for any person accompanying the patient into the magnet room. There are certain answers that will absolutely contraindicate the patient being scanned (e.g., if the patient has a cardiac pacemaker or ferromagnetic implant) while other questions are more designed to evaluate the patientâs tolerance (such as whether they are claustrophobic). Other questions (such as those relating to renal disease) will determine if it is safe to use a contrast agent and make the physician aware of the medical status of the patient.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145337/1/cpmix01.pd
Ventricular Assist Device implant (AB 5000) prototype cannula: In vitro assessment of MRI issues at 3-Tesla
Educational background civil servants have when dealing with retarded public offenders
Due to the lack of knowledge on the part of our public servants, the retarded offender is, on occasion, falsely accused and unjustly treated. This paper will attempt to examine the educational preparation of the personnel dealing with the retarded offender at the time he comes in contact with these various people
The Marine Environment, Human Well-being and Environmental Valuation: a case study from Plymouth, UK.
There has been increasing acknowledgement that environmental change is inextricably linked to changes in well-being. Despite this there is no consensus on the definition of well-being or valuation method(s) upon which to base policy evaluations for well-being. The thesis examines this issue by comparing and contrasting two approaches to measuring well-being benefits from marine and coastal environments: (1) the preference-based approach and (2) the experiential approach, with reference to two exemplar methods for valuing non-market marine and coastal goods within each paradigm: the Contingent Valuation Method (CVM) and the Life Satisfaction Approach (LSA). The thesis begins with a comprehensive review of the two methods, identifying areas of criticism and contrasting their respective strengths and weaknesses. This is followed by an empirical comparison of the two methods. This comparison was made possible by a local coastal regeneration project that occurred during the course of the PhD project (Teatâs Hill, Plymouth, UK) and enabled an evaluation before and after the environmental intervention. A repeat cross-sectional survey was used to place a monetary value on the provision of the coastal regeneration using the two methods. The CVM was used to value the intervention before implementation. The LSA examined well-being before and after the implementation to value the effect of the regeneration on life satisfaction. Results of the CVM suggest that respondents would be willing to pay a monetary value of ÂŁ7.97 (as a one-off payment) for the regeneration project. Results of the LSA suggested that life satisfaction was on average 3.89% higher for people interviewed after the regeneration, compared to people interviewed before the regeneration, after adjusting for relevant visit and individual level controls. The analysis also explored the potential of estimating a monetary value using the LSA, to enable a direct comparison with the estimate from the CVM. The analysis indicated that ÂŁ1,925.45 is the amount of money that an average household would be willing to give up for the provision of the coastal regeneration given that utility stays constant. The research in this thesis presents a number of new findings which have important implications for the valuation of coastal interventions and the use of well-being research in environmental policy, planning and decision-making.Natural Environment Research Council (NERC
How to build and maintain trust at the interface of policy and research, insights from a century of boundary spanning
Trust is often invoked as a key ingredient to establishing effective relationships between researchers, their research, and policymakers. In this post, Christopher Cvitanovic and Rebecca Shellock discuss their research on trust in practice. Drawing on their study into ICES (the International Council for the Exploration of the Seas), they outline lessons and processes in building and maintaining trust informed by the organisationâs extensive experience of connecting research to policy
Biological Effects and Safety in Magnetic Resonance Imaging: A Review
Since the introduction of Magnetic Resonance Imaging (MRI) as a diagnostic technique, the number of people exposed to electromagnetic fields (EMF) has increased dramatically. In this review, based on the results of a pioneer study showing in vitro and in vivo genotoxic effects of MRI scans, we report an updated survey about the effects of non-ionizing EMF employed in MRI, relevant for patientsâ and workersâ safety. While the whole data does not confirm a risk hypothesis, it suggests a need for further studies and prudent use in order to avoid unnecessary examinations, according to the precautionary principle
Rule Out (R/O) Arteriovenous Malformation
When imaging patients for intracranial arteriovenous malformations, the goals are: (1) to determine if an arteriovenous malformation is present; (2) to assess size, shape, and location of the nidus; (3) to determine potential arterial feeders and venous drainage routes (including screening for aneurysms on arterial feeders); and (4) to determine the state of the surrounding brain parenchyma, including the identification of intracranial hemorrhage. A postâcontrast 3âD spoiled gradient echo (SPGR) sequence is used for sequences 1 to 3. Standard MR imaging sequences are used to evaluate the brain parenchyma. The protocol contained within this unit can be used for the evaluation of stable patients. In order to perform the optional sequences with perfusion and diffusion studies, a scanner with echoplanar capabilities is required; however, the standard anatomical MR imaging sequences included in the protocols do not require these faster gradients.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145196/1/cpmia0105.pd
Aortic Dissection
This unit presents a for imaging of thoracic aoprta to rule out aortic dissection. The core components of the imaging protocol are ECG (electrocardiograph)âgated black blood HASTE (half Fourier single shot turbo spin echo), and contrastâenhanced MR angiography (MRA). When no abnormal findings are seen in black blood HASTE or cine sequences, it is somewhat controversial whether contrastâenhanced MRA is necessary. An based on a time of flight (TOF) sequence is presented which can be used instead of contrastâenhanced MRA.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145253/1/cpmia1201.pd
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