27 research outputs found
A Survey on the Current Status and Future Challenges Towards Objective Skills Assessment in Endovascular Surgery
Minimally-invasive endovascular interventions have evolved rapidly over the past decade, facilitated by breakthroughs in medical
imaging and sensing, instrumentation and most recently robotics. Catheter based operations are potentially safer and applicable to
a wider patient population due to the reduced comorbidity. As a result endovascular surgery has become the preferred treatment
option for conditions previously treated with open surgery and as such the number of patients undergoing endovascular interventions
is increasing every year. This fact coupled with a proclivity for reduced working hours, results in a requirement for efficient training
and assessment of new surgeons, that deviates from the âsee one, do one, teach oneâ model introduced by William Halsted, so
that trainees obtain operational expertise in a shorter period. Developing more objective assessment tools based on quantitative
metrics is now a recognised need in interventional training and this manuscript reports the current literature for endovascular skills
assessment and the associated emerging technologies. A systematic search was performed on PubMed (MEDLINE), Google Scholar,
IEEXplore and known journals using the keywords, âendovascular surgeryâ, âsurgical skillsâ, âendovascular skillsâ, âsurgical training
endovascularâ and âcatheter skillsâ. Focusing explicitly on endovascular surgical skills, we group related works into three categories
based on the metrics used; structured scales and checklists, simulation-based and motion-based metrics. This review highlights the
key findings in each category and also provides suggestions for new research opportunities towards fully objective and automated
surgical assessment solutions
Computational fluid dynamics modelling in cardiovascular medicine
This paper reviews the methods, benefits and challenges associated with the adoption and translation of computational fluid dynamics (CFD) modelling within cardiovascular medicine. CFD, a specialist area of mathematics and a branch of fluid mechanics, is used routinely in a diverse range of safety-critical engineering systems, which increasingly is being applied to the cardiovascular system. By facilitating rapid, economical, low-risk prototyping, CFD modelling has already revolutionised research and development of devices such as stents, valve prostheses, and ventricular assist devices. Combined with cardiovascular imaging, CFD simulation enables detailed characterisation of complex physiological pressure and flow fields and the computation of metrics which cannot be directly measured, for example, wall shear stress. CFD models are now being translated into clinical tools for physicians to use across the spectrum of coronary, valvular, congenital, myocardial and peripheral vascular diseases. CFD modelling is apposite for minimally-invasive patient assessment. Patient-specific (incorporating data unique to the individual) and multi-scale (combining models of different length-And time-scales) modelling enables individualised risk prediction and virtual treatment planning. This represents a significant departure from traditional dependence upon registry-based, populationaveraged data. Model integration is progressively moving towards 'digital patient' or 'virtual physiological human' representations. When combined with population-scale numerical models, these models have the potential to reduce the cost, time and risk associated with clinical trials. The adoption of CFD modelling signals a new era in cardiovascular medicine. While potentially highly beneficial, a number of academic and commercial groups are addressing the associated methodological, regulatory, education-And service-related challenges
Arterial Tissue Perforation Using Ultrasonically Vibrating Wire Waveguides
Chronic Total Occlusions (CTOs) are fibrous and calcified atherosclerotic lesions which completely occlude the artery. They are difficult to treat with standard dilation procedures as they cannot be traversed easily. Their treatment is also associated with a high risk of arterial perforation. Low frequency ultrasonic vibrations delivered via wire waveguides represent a minimally invasive treatment for CTOs and other tissue ablation applications. These devices typically operate at 20â50 kHz delivering wire waveguide distal tip amplitudes of vibration of 0-60 ÎŒm. The diseased tissue is ablated or disrupted by repetitive direct mechanical contact and cavitation. This research assesses the susceptibility of arterial tissue to perforation and residual damage under the action of ultrasonically energised wire waveguides. Using Finite Element Analysis (FEA), a linear acoustic model of the wire waveguide distal tips can predict the pressures for a range of operating parameters typically used for these devices. High mesh densities (140 EPW) were required to solve the entire acoustic field, including complex wave interactions. The FEA model was used to aid in the further design and modification of an ultrasonic apparatus and wire waveguide (0â34.3 ÎŒm at 22.5 kHz). Using a test rig, the effects of distal tip amplitudes of vibration, feedrate and angled entry on the perforation forces, energy and temperature were measured. The perforation forces reduced (â 60%, 6.13 N - 2.46 N mean) when the wire waveguide was energised at low amplitudes of vibrations (\u3c 27.8 ÎŒm). There were no significant change in tissue perforation forces above this or when the waveguide was operating above the cavitation threshold. Histological analysis also showed tissue removal. While this knowledge is useful in the prediction and avoidance of perforations during CTO operations; it is also envisaged that this information can aid in the design and development of generic ultrasonic wire waveguide tissue cutting tools
Real-Time Magnetic Resonance Imaging
Realâtime magnetic resonance imaging (RTâMRI) allows for imaging dynamic processes as they occur, without relying on any repetition or synchronization. This is made possible by modern MRI technology such as fastâswitching gradients and parallel imaging. It is compatible with many (but not all) MRI sequences, including spoiled gradient echo, balanced steadyâstate free precession, and singleâshot rapid acquisition with relaxation enhancement. RTâMRI has earned an important role in both diagnostic imaging and image guidance of invasive procedures. Its unique diagnostic value is prominent in areas of the body that undergo substantial and often irregular motion, such as the heart, gastrointestinal system, upper airway vocal tract, and joints. Its value in interventional procedure guidance is prominent for procedures that require multiple forms of softâtissue contrast, as well as flow information. In this review, we discuss the history of RTâMRI, fundamental tradeoffs, enabling technology, established applications, and current trends
A Clinician's Contribution to Biomedical Engineering in Experimental Echocardiography
The research of this thesis has been focused on the biomedical engineering aspects of new
techniques of echocardiography. In close collaboration with the engineers of the Experimental
Echocardiography Department of the Thoraxcentre, Erasmus University, Rotterdam, new methods
to measure coronary blood flow and arterial wall elasticity with intravascular ultrasound (IVUS)
have been developed. We have also investigated the clinical application of these measurements and
have tried to improve traditional techniques based on intracoronary Doppler wires. In another field,
we have developed a method to determine the radiation dose delivered in the wall of coronary
arteries treated with brachytherapy. in collaboration with the Emory University, Atlanta, GA. This
method utilizes 3-dimensional IVUS reconstruction combined with radiotherapy treatment planning.
Finally, the tools developed for the recording of the signals of intracoronary Doppler wires have
been adapted, during a stay at the Cleveland Clinic Foundation, OK for the study of left ventricular
mechanics and the compliance of the large arteries. This has been achieved by simultaneous
acquisition of non-invasive pressure (with tonometry) and flow (with transthoracic Doppler
echocardiography) signals. The fruits of an old and close collaboration with the Institute
Biomedical Technology of the Ghent University can also be found in different chapters. This work
is subdivided in five major parts, and a detailed introductory chapter precedes each one