Organ motion can cause artefacts in abdominal imaging particularly with magnetic resonance imaging (MRI), and may often limit the diagnostic quality of an image. If spatial resolution and image quality are to improve in MRI and other imaging techniques, a more detailed understanding of organ motion is required. Despite the importance of organ motion little quantitative information is available to date. This study was the continuation of work instigated to investigate and quantify respiratory movements of upper abdominal organs for a group of healthy volunteers in order to provide the design criteria for a motion test object for use in MRI. A previous phase of the project allowed construction of a test object but refinements were needed to represent respiratory motion more closely as a consequence of the data presented in this paper. Improvements in the scanning technique and the recording procedure have revealed that, contrary to our initial findings, motion of the diaphragm and liver is predominantly in the superior-inferior (SI) direction with an average displacement (+/- SD) (quiet respiration) of 12 +/- 7 mm (range 7-28 mm) and 10 +/- 8 mm (range 5-17 mm), respectively. For some volunteers, motion of the kidneys can be complex, especially during deep inspiration. New data have been provided by this phase of the motion study on the displacement, velocity and acceleration of abdominal organs as a function of time. These data show that MRI motion artefact reduction techniques which assume that either organ displacement, velocity or acceleration are constant are only applicable during certain phases of the respiratory cycle.
BackgroundExtravasation injury remains an important cause of iatrogenic injury in neonatal intensive care. This study aims to describe the current approach to extravasation injury (EI) prevention and management in Neonatal Intensive Care Units (NICUs) in Australia and New Zealand.MethodsA literature review regarding extravasation injury in the newborn was carried out to inform questionnaire design. An internet-based survey was then conducted with the clinical directors of the 27 tertiary NICUs in Australia and New Zealand.ResultsThe survey received a 96% response rate. Approximately two thirds of Australian and New Zealand NICUs have written protocols for prevention and management of extravasation injury. Considerable practice variation was seen for both prevention and treatment of EI. 92% of units had experienced cases of significant EI.ConclusionsAustralian and New Zealand tertiary neonatal units clearly recognise EI as an important cause of iatrogenic morbidity and mortality. Significant variation still exists among units with regards to guidelines for both prevention and management of EI. We recommend that neonatal staff should remain vigilant, ensuring that guidelines for the prevention and treatment of EI are available, and rigorously followed.
Optical experiments are described for measuring the attenuation characteristics of breast tissues at visible and near-infrared wavelengths. Total attenuation coefficients post mortem were measured directly in thin tissue sections. They are usually within the range from 10 to 30 mm-1, are rather higher in fat than in fibroglandular specimens and decrease with increasing wavelength. The scattering phase function is strongly forward-peaked with the mean cosine of scattering in the range from 0.85 to 0.97 and appearing more forward-peaked in fat than in fibroglandular tissue. The reduced scattering coefficient is of the order of 1 mm-1 in all tissues. Absorption coefficients were measured indirectly in optically thick sections. They are typically between 0.1 and 0.5 mm-1 at wavelengths around 580 nm and an order of magnitude lower at 850 nm. At 580 nm and shorter wavelengths the absorption in carcinoma is significantly higher than in adjacent uninvolved tissue. Significant differences were observed in the first-order derivatives of the transmission spectra of carcinoma and surrounding tissues at certain infrared wavelengths. Transmission spectra measured in vivo across the wavelength range from 500 to 860 nm have a similar form to the spectra of excised samples. Linear absorption coefficients are generally of the same order of magnitude as those found in vitro although they are lower at green wavelengths.
We have evaluated oesophageal function in 34 diabetics and in 16 non-diabetic controls by a timed bolus transit method derived from dynamic oesophageal scintiscans (water transit time: WTT) and barium swallow. The diabetics were screened for autonomic neuropathy using standard cardiovascular responses and 10 patients were classified as abnormal. WTT was significantly prolonged in autonomic neuropaths compared with other diabetics (p less than 0.01) and controls (p less than 0.001). Abnormal peristalsis on barium swallow was seen more frequently in autonomic neuropaths (9/10) than in other diabetics (11/24, p less than 0.002). WTTs from all diabetic patients correlated with abnormal heart rate responses at rest (Rs = - 0.49, p less than 0.005), on deep inspiration (Rs = -0.48, p less than 0.005), and on standing (Rs = -0.39, p less than 0.025) but not with the Valsalva manoeuvre. A weaker correlation was found between the postural fall in blood pressure (Rs = 0.3, p less than 0.05). Diabetics with autonomic neuropathy frequently have asymptomatic oesophageal dysfunction which may result from a vagal neuropathy in view of its association with abnormalities of vagally mediated cardiovascular responses.
This is the first study to examine attitudes and perceptions of midwives and doctors to vitamin K prophylaxis in neonates. Considerable discrepancies in attitude are evident, and in some midwives, a lack of confidence in this intervention is apparent. How this affects education to families is unknown. Increased understanding of this phenomenon, along with improved education and communication to professionals and families, is required.
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