A model-based radiostereometric analysis (MBRSA) is a method for precise measurement of prosthesis migration, which does not require marking the implant with tantalum beads. Instead, the prosthesis pose is typically recovered using a feature-based 2D-3D registration of its virtual model into a stereo pair of radiographs. In this study, we evaluate a novel intensity-based formulation of previously published nonoverlapping area (NOA) approach. The registration is capable of performing with both binary radiographic segmentations and nonsegmented X-ray images. In contrast with the feature-based version, it is capable of dealing with unreliable parts of prosthesis. As the straightforward formulation allows efficient acceleration using modern graphics adapters, it is possible to involve precise high-poly virtual models. Moreover, in case of binary segmentations, the nonoverlapping area is simply interpretable and useful for indicating the accuracy of the registration outcome. In silico and phantom evaluations were performed using a cementless Zweymüller femoral stem and its reverse engineered (RE) model. For initial pose estimates with difference from the ground-truth limited to ±4 mm and ±4°, respectively, the mean absolute translational error was not higher than 0.042 ± 0.035 mm. The error in rotation around the proximodistal axis was 0.181 ± 0.265°, and the error for the remaining axes was not higher than 0.035 ± 0.037°.
- MeSH
- analýza selhání vybavení metody MeSH
- fantomy radiodiagnostické MeSH
- femur diagnostické zobrazování MeSH
- kyčelní protézy MeSH
- lidé MeSH
- počítačové zpracování obrazu metody MeSH
- radiostereometrická analýza metody MeSH
- tantal MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Wear is a fundamental problem in relation to the life-time of the hip joint implants, especially for the components of the ultra-high molecular weight polyethylene (UHMWPE). Therefore, the better understanding of the properties and capabilities of UHMWPE related to wear is crucial for the improvement of the implants' behavior. The purpose of this study is to present a new methodology for calculating volumetric wear of retrieved hip prostheses using a combination of novel co-ordinate measuring machine data and Matlab GUI program (Mathworks, Inc.). Method utilizes the unworn portion of the explanted acetabular cup to create or reconstruct the original unworn surface. From these unworn surfaces, it is possible to directly calculate volumetric wear and to graphically map the wear scar, i.e. the penetration of the femoral head into the acetabular cup.
Mobile technologies are constantly evolving and with the development of Internet of Things we can expect continuous increase of various applications. Mobile technologies have undeniable opportunities to play an important role in health services. Concerning purely technical aspects, almost every problem can be solved. However, there are still many unsolved and unclear issues related with ethics and governance mechanisms for mobile phone applications. These issues are even more critical in medical and health care applications of mobile technologies. This paper tries to analyse ethical, and privacy-related challenges that may occur when introducing Personal Portable Devices (PPD) to collect and record personal health data in health care and welfare environment.
- MeSH
- analýza selhání vybavení metody MeSH
- design vybavení etika MeSH
- důvěrnost informací zákonodárství a právo MeSH
- internet etika zákonodárství a právo MeSH
- mobilní aplikace etika zákonodárství a právo MeSH
- telemedicína etika zákonodárství a právo MeSH
- zabezpečení počítačových systémů etika zákonodárství a právo MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The clinical practice shows that the loosening of acetabular cups is more frequent than stem loosening. With standard cups, the incidence of dislocation failure is highest in the first year after arthroplasty implantation. The aim of the study was to quantitatively evaluate the implant-bone stability of a cementless acetabular cup prosthesis by using a device based on resonance frequency analysis. The evaluation of this device was done by finite element analysis and in vitro experiments. It was shown that not all the resonance frequencies can be measured by our device. The resonance frequencies vary within the range of 500-3000 Hz. The proposed power spectrum measurement gives the information about the absolute stiffness of the press-fit implant.
- MeSH
- acetabulum fyziologie chirurgie MeSH
- analýza metodou konečných prvků MeSH
- analýza selhání vybavení metody MeSH
- biologické modely * MeSH
- kyčelní protézy MeSH
- lidé středního věku MeSH
- lidé MeSH
- mechanický stres MeSH
- modul pružnosti fyziologie MeSH
- náhrada kyčelního kloubu přístrojové vybavení metody MeSH
- oscilometrie metody MeSH
- počítačová simulace MeSH
- protetické vybavení metody MeSH
- reprodukovatelnost výsledků MeSH
- senzitivita a specificita MeSH
- vibrace MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The objective of this study is to investigate the effect of multiple dead elements in an ultrasound probe on the accuracy of Doppler ultrasound measurements. For this work, we used a specially designed ultrasound imaging system, the Ultrasonix Sonix RP, that provides the user with the ability to disable selected elements in the probe. Using fully functional convex, linear, and phased array probes, we established a performance baseline by measuring the parameters of a laminar parabolic flow profile. These same parameters were then measured using probes with 1 to 10 disabled elements. The acquired velocity spectra from the functional probes and the probes with disabled elements were then analyzed to determine the overall Doppler power, maximum flow velocity, and average flow velocity. Color Flow Doppler images were also evaluated in a similar manner. The analysis of the Doppler spectra indicates that the overall Doppler power as well as the detected maximum and average velocities decrease with the increasing number of disabled elements. With multiple disabled elements, decreases in the detected maximum and average velocities greater than 20% were recorded. Similar results were also observed with Color Flow Doppler measurements. Our results confirmed that the degradation of the ultrasound probe through the loss of viable elements will negatively affect the quality of the Doppler-derived diagnostic information. We conclude that the results of Doppler measurements cannot be considered accurate or reliable if there are four or more contiguous dead elements in any given probe.
- MeSH
- analýza selhání vybavení metody statistika a číselné údaje MeSH
- design vybavení MeSH
- fantomy radiodiagnostické MeSH
- reprodukovatelnost výsledků MeSH
- selhání zařízení MeSH
- senzitivita a specificita MeSH
- ultrasonografie dopplerovská barevná přístrojové vybavení metody MeSH
- ultrasonografie dopplerovská přístrojové vybavení metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The aim of the study was to determine the relationship between implant-associated complications and Dynamic Hip Screw (DHS) placement in the femoral neck, based on a Finite Element (FE) Analysis. Very diverse implant failures and subsequent complications can be encountered after introduction of the DHS. We evaluated 308 dynamic hip screw osteosyntheses for pertrochanteric fractures in 297 patients. The ABAQUS 6.9 program was used for development of the FE model, and the analyses were performed in 5 modelled situations corresponding to five different screw locations. Complications occurred in 10% of patients and re-operation was necessary in 3.9%. The highest risk of implant failure was associated with the screw situation in the upper third of the femoral neck. Placing a dynamic hip screw in the middle third of the neck significantly reduced stresses in the plate and screw. The screw position in the upper third of the neck significantly increased these stresses. The finite element analysis confirmed our clinical experience that the optimum position of the dynamic hip screw is in the middle third of the femoral neck.
- MeSH
- analýza selhání vybavení * metody statistika a číselné údaje MeSH
- fraktury krčku femuru * chirurgie radiografie MeSH
- fraktury kyčle chirurgie radiografie MeSH
- kostní šrouby MeSH
- lidé středního věku MeSH
- lidé MeSH
- mechanický stres MeSH
- počítačová simulace MeSH
- reoperace statistika a číselné údaje MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- vnitřní fixace fraktury * metody přístrojové vybavení škodlivé účinky MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
- srovnávací studie MeSH
AIM: To find out whether it is possible to anaesthetize patients safely without analgesia and sedation, using burst pacing prolonged until the patient becomes unconscious. METHODS: One hundred and four patients undergoing implantation or reimplantation of a cardioverter-defibrillator were included. Patients randomized into Group B underwent prolonged burst pacing without analgesia and sedation. Patients in Group T underwent a T-wave shock under analgesia and sedation. Blood samples for measurement of serum neuron-specific enolase were taken before surgery and 6, 24, and 48 h after the procedure. RESULTS: From the 104 patients, 51 were randomly assigned to Group B and 53 to Group T. Four patients from Group B were switched to Group T (ventricular fibrillation not induced by burst pacing). The clinical characteristics of both groups were similar. The mean total time of cardiac arrest was significantly longer in Group B (23.0 ± 4.4 s, median 22.7) vs. Group T (10.3 ± 3.0 s, median 10.0), P < 0.0001 (Mann-Whitney U-test). The effectiveness of both induction methods was similar (92.1% in Group B and 100% in Group T). The mean neuron-specific enolase levels after 6, 24, and 48 h were similar in Groups B and T (13.1 ± 6.3 and 11.6 ± 5.8 mg/L, 14.5 ± 7.5 and 13.4 ± 6.0 mg/L, and 14.9 ± 5.9 and 12.2 ± 6.0 mg/L, respectively) as were these levels compared with baseline neuron-specificenolase levels (14.0 ± 5.9 and 13.4 ± 4.0 mg/L, respectively), P = NS for all. CONCLUSION: Despite a longer time of total cardiac arrest, prolonged burst pacing appears to be a safe and effective method for induction of ventricular fibrillation during cardioverter-defibrillator testing, which enables omission of analgesia and sedation or general anaesthesia.
- MeSH
- analýza selhání vybavení přístrojové vybavení metody MeSH
- defibrilátory implantabilní škodlivé účinky MeSH
- elektrická defibrilace přístrojové vybavení metody MeSH
- elektrofyziologické techniky kardiologické metody MeSH
- fibrilace komor diagnóza prevence a kontrola MeSH
- lidé středního věku MeSH
- lidé MeSH
- senioři MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- randomizované kontrolované studie MeSH
This paper describes a new device and a method to determine the radon diffusion coefficient in damp-proof membranes developed in the Czech Republic. The main advantage of the device is that it enables tests to be carried out in all the known measuring modes used throughout Europe. Two recently developed computer programs are presented for the numerical modelling of the time-dependent radon transport through damp-proof membranes. According to this method, the radon diffusion coefficient is derived from the process of fitting the numerical solution to the measured curve of radon concentration in a receiver container. Numerical simulation and measured data are also compared. Reasons for disagreements between different methods and specific configurations of the measuring device are also discussed.
Lead and implantable cardioverter defibrillator (ICD) device failure is a severe problem in ICD therapy and may occur without preceding signs of deterioration. Insulation lead failure and subsequent ICD defect 7 months after ICD implantation for secondary prevention of sudden cardiac death (SCD) in a 70-year-old male was automatically detected with the Home Monitoring system. Immediate lead and device replacement was performed. This case illustrates the benefit of permanent automatic remote monitoring of implanted active devices.
- MeSH
- analýza selhání vybavení metody MeSH
- defibrilátory implantabilní MeSH
- elektrická vodivost MeSH
- implantované elektrody MeSH
- lidé MeSH
- selhání zařízení MeSH
- senioři MeSH
- telemedicína metody MeSH
- terapie s pomocí počítače metody MeSH
- vektorkardiografie metody MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- Publikační typ
- kazuistiky MeSH
