Computer methods and programs in biomedicine
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Comput Methods Programs Biomed · Mar 2011
Impact of aortic repair based on flow field computer simulation within the thoracic aorta.
Purpose of this computational study is to examine the hemodynamic parameters of velocity fields and shear stress in the thoracic aorta with and without aneurysm, based on an individual patient case and virtual surgical intervention. These two cases, case I (with aneurysm) and II (without aneurysm), are analyzed by computational fluid dynamics. The 3D Navier-Stokes equations and the continuity equation are solved with an unsteady stabilized finite element method. ⋯ The computed results show velocity profiles skewed towards the inner aortic wall for both cases in the ascending aorta and in the aortic arch, while in the descending aorta these velocity profiles are skewed towards the outer aortic wall. Computed streamlines indicate that flow separation occurs at the proximal edge of the aneurysm, i.e. computed flow enters the aneurysm in the distal region, and that there is essentially a single, slowly rotating, vortex within the aneurysm during most of the systole. In summary, after virtual surgical intervention in case II higher shear stress distribution along the descending aorta could be found, which may produce more healthy reactions in the endothelium and benefit of vascular reconstruction of an aortic aneurysm at this particular location.
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Comput Methods Programs Biomed · Dec 2010
Comparative StudyComparison of documentation time between an electronic and a paper-based record system by optometrists at an eye hospital in south India: a time-motion study.
The adoption of electronic medical record (EMR) system is gradually increasing. However, various time-motion studies reveal conflicting data regarding time effectiveness on workflow due to computerization. One of the major issues for physicians is their uncertainty with EMRs' potential impact of time on workflow. A tertiary eye hospital in south India was in the process of implementing an EMR system in their ambulatory care unit. Many of the staff did not have previous computing experience and there were conflicting views on the time effectiveness of the computerized system after implementation. The management was thus interested to know the real time effectiveness of EMR in their hospital. The study compliments existing studies of this type by comparing the time efficiency of documentation time using EMR system with paper documentation in a hospital in a developing country where a transition between paper and EMR documentation was currently in progress. ⋯ EMR systems can be adopted in eye hospitals without having significant negative impact on duration of consultation and documentation for optometrists. More time-motion studies that include ophthalmologists are however needed in order to get a more complete picture of time impact of the EMR system on clinical workflow in eye hospitals.
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Comput Methods Programs Biomed · Dec 2010
Dynamic composition of medical support services in the ICU: Platform and algorithm design details.
The Intensive Care Unit (ICU) is an extremely data-intensive environment where each patient needs to be monitored 24/7. Bedside monitors continuously register vital patient values (such as serum creatinine, systolic blood pressure) which are recorded frequently in the hospital database (e.g. every 2 min in the ICU of the Ghent University Hospital), laboratories generate hundreds of results of blood and urine samples, and nurses measure blood pressure and temperature up to 4 times an hour. The processing of such large amount of data requires an automated system to support the physicians' daily work. ⋯ In addition to the automatic composition the paper also proposes a recovery mechanism in case of unavailable services. When executing the composition of medical services, unavailable services are dynamically replaced by equivalent services or a new composition achieving the same result. The presented platform and QoS algorithms are put through extensive performance and scalability tests for typical ICU scenarios, in which basic medical services are composed to a complex patient monitoring service.
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Comput Methods Programs Biomed · Jul 2010
Finite element modelling of paediatric head impact: global validation against experimental data.
Biomechanics of the human head has been widely studied for several decades. At a mechanical level, the use of engineering and finite element (FE) methods has allowed injury mechanisms to be investigated using biofidelic FE models. These models are generally validated using experimental data then used to simulate real-world head trauma in order to derive numerical tolerance limits, leading to efficient injury predicting tools. ⋯ However injury biomechanics on paediatric population is emerging with experimental tests on the paediatric cadavers or tests on biological tissue and the development of finite element models. The present paper proposes a new finite element model of a newborn head, simulating its main features, with material properties from the literature. Global validation of the model against experimental data in terms of skull deflection is performed and the model is used to simulate paediatric skull fracture coming from real-world head trauma.
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Comput Methods Programs Biomed · May 2010
Toward fully automated processing of dynamic susceptibility contrast perfusion MRI for acute ischemic cerebral stroke.
We developed fully automated software for dynamic susceptibility contrast (DSC) MR perfusion-weighted imaging (PWI) to efficiently and reliably derive critical hemodynamic information for acute stroke treatment decisions. Brain MR PWI was performed in 80 consecutive patients with acute nonlacunar ischemic stroke within 24h after onset of symptom from January 2008 to August 2009. These studies were automatically processed to generate hemodynamic parameters that included cerebral blood flow and cerebral blood volume, and the mean transit time (MTT). ⋯ Results of image quality assessment by two observers revealed that the MTT maps exhibited superior quality over the TTP maps (88% good rating of MTT as compared to 68% of TTP). Our software allowed fully automated deconvolution analysis of DSC PWI using proven efficient algorithms that can be applied to acute stroke treatment decisions. Our streamlined method also offers promise for further development of automated quantitative analysis of the ischemic penumbra.