![]() myocardial infarction or cardiomyopathy, geometry, dynamics and function of the heart muscle and valves may alter significantly. Under pathophysiological conditions such as e.g. The heart is a predominantly muscular, hollow organ that-under physiological conditions at rest-beats rhythmically 60–80/min. Future improvements including the implication of marker identification algorithms and data analysis software could allow almost real-time quantitative analyses of distinct cardiac structures with high temporal and spatial resolution. However, marker identification still requires substantial manual work. The method presented in this case study allowed quantitative data analyses of radiopaque cardiac markers that were tracked fully automated with high temporal resolution. Data sets were then analyzed quantitatively using customized software. Rotation of the 3-dimensional model allowed the identification of the precise anatomical position for each marker. The fast moving leaflet marker was identified by using video loops constructed of all recorded frames. First, cylindrical markers were manually separated from spherical markers, thus allowing to distinguish right from left heart markers. The anatomical marker locations were identified using a 3-dimensional model of a single frame containing all tracked markers. ![]() Radiopaque marker coordinates were determined fully automated using novel tracking algorithms. Data were acquired with a biplanar X-ray acquisition system (Neurostar R, Siemens AG, 500 Hz). In addition, 13 cylindrical tantalum markers were implanted into the left ventricle. In one adult sheep, twenty silver balls were sutured to the right side of the heart: 10 to the tricuspid annulus, one to the anterior tricuspid leaflet and nine to the epicardial surface of the right ventricle. In this case study we describe the steps from the generation of three-dimensional marker coordinates to quantitative data analyses in an in vivo ovine model. However, the methodology did not allow to assign the exact anatomical location to each marker. Further experimentation is recommended to ascertain the same.Recently, algorithms were developed to track radiopaque markers in the heart fully automated. It is not feasible to determine the clinical impact of this localized corrosion behavior from this in vitro study. However, the surface condition of the stent corpus and the mode of attachment of the marker onto the corpus may have a significant impact on the uniformity of the final corrosion behavior. Stent radiopacity can be increased significantly with the help of radiopaque markers (p < 0,0001 LX vs. Also, the average E bd values for the SMR stents were better than those exhibited by the PS stents (503 +/- 107 mV vs SCE). The SMR stents exhibited the highest E bd values (802 +/- 112 mV vs SCE), while the LX stents exhibited the lowest E bd values (155 +/- 38 mV vs SCE). ![]() At 7.5 p/s (standard fluoro mode) the LX was considered to be well to very well visible in 77 %, followed by the SMR in 12.5 %, the SM in 1 %, and the FX in 0 %. The corrosion current density (I corr ) and the breakdown value (E bd ) were compared parameters of interest.Īt the spotfilm mode the LX, the SM and the SMR were rated well to very well visible in 99 %, 96 %, 96 %, and the FX only in 64 %. Palmaz-Schatz stents (n = 3) were used as the control group for comparative evaluation. LX and SMR stents (n = 5/group) were subjected to potentiodynamic polarization testing in de-aerated Hanks salt solution at 37 degrees C using a potentiostat. Four readers evaluated a total of 3200 images (160 per stent per fluoro mode) according to the following radiopacity score (RS): 0 = no stent visible, 1 = poor, 2 = acceptable, 3 = good, and 4 = very good stent visibility. The radiopacity of the following stents was evaluated at different fluoroscopy modes (spotfilm, continuous fluoroscopy, 15 p/s, 7.5 p/s, 3 p/s): Memotherm Flexx (FX), Memotherm Luminexx (LX)(Bard), SMART (SM), SMARTeR (SMR)(Cordis). The secondary objective was to investigate the impact of such radiopaque markers on localized corrosion at the stent corpus-marker interfaces. ![]() The primary objective of this study was to evaluate the impact of radiopaque markers on stent visibility. ![]()
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