In this work, we propose a simple method to simultaneously match the refractive index and kinematic viscosity of a circulating blood analog in hydraulic models for optical flow measurement techniques (PIV, PMFV, LDA, and LIF). The method is based on the determination of the volumetric proportions and temperature at which two transparent miscible liquids should be mixed to reproduce the targeted fluid characteristics. The temperature dependence models are a linear relation for the refractive index and an Arrhenius relation for the dynamic viscosity of each liquid. Then the dynamic viscosity of the mixture is represented with a Grunberg-Nissan model of type 1. Experimental tests for acrylic and blood viscosity were found to be in very good agreement with the targeted values (measured refractive index of 1.486 and kinematic viscosity of 3.454 milli-m2/s with targeted values of 1.47 and 3.300 milli-m2/s).

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The purpose of this study was to determine whether the use of a scalpel or electrocautery to remove radioactive sealed sources ("seeds") from surgically excised tissue could damage the seed and cause it to leak its radioactive contents. Attempts were made to cut or burn Oncura Model 6711 non-radioactive seeds while in pig muscle or on a stainless steel plate. Additionally, one active 125I seed was purposely charred using pressure with an electrocautery knife to see whether the casing could be damaged. Electron microscopy scanning was performed on the dummy seeds to determine if the integrity of the metal casing had been compromised. Two types of leak tests were performed on the active seed to verify the presence or absence of loose contamination. The seed casing was not damaged from either use of a scalpel or electrocautery when the seed was in tissue. The active seed was not found to be leaking after applying pressure with an electrocautery knife while the seed was on a stainless steel plate. We conclude that removal of active Model 6711 seeds from surgically excised tissue can be done safely with a scalpel or electrocautery because constant, firm pressure cannot be applied to the seed. This is likely true for seeds made of similar materials.

Background: Several contrast media (CM) are used for diagnostic angiography and coronary percutaneous interventions. Catheter miniaturization allows performance of most diagnostic studies using 4-5 F catheters and interventions using 5-6 F catheters. As a result of catheter lumen downsizing and viscosity of CM, the operators are sometimes required to forcefully inject to produce adequate images. Methods and Results: The aim of the study is to perform a comparative rheology analysis between three different commonly used CM: iso-osmolar, nonionic iodixanol, Visipaque 1 , (GE Healthcare); low-osmolar, nonionic ioversol, Optiray 1 ; and low-osmolar, ionic ioxaglate, Hexabrix 1 , (Tyco Healthcare, US). The viscosity was experimentally assessed for temperature varying from 14 to 408C. To reproduce clinical use, an experimental set-up was used and the pressure developed to inject CM was evaluated at different temperatures and compared between the three CM. All three agents demonstrated a nonlinear inverse relationship between temperature and viscosity. At 148C iodixanol showed a twofold increase in viscosity compared with ioversol and ioxaglate. At 408C, the difference was reduced to 27%. At room temperature (208C), the difference in pressure needed to inject CM was 10% between iodixanol and ioxaglate and 6% between iodixanol and ioversol. As the temperatures increased, the differences in pressure became less important, becoming negligible (1%) at 378C. Conclusion: The viscosity of the iso-osmolar nonionic contrast agent iodixanol showed a stronger dependence on temperature compared with ioversol and ioxaglate. The impact of differences in viscosity and pressure to inject between CM were minimized at 378C. This emphasizes the importance of temperature control when using current lowosmolar CM and iso-osmolar CM with smaller sized catheters. '

Cardiovascular diseases are the leading cause of morbidity and mortality in Canada and other western countries. In that context, understanding the mechanics involved in the aorta can lead to better comprehension of the interaction of blood flow and wall mechanics in normal and pathologic conditions. In this work, we present the methodologies to create physical models of the aorta for flow visualization purposes in order to assess the effects of compliance.

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Intracoronary ultrasound (ICUS) provides high-resolution transmural images of the arterial wall. By performing a pullback of the ICUS transducer and three-dimensional reconstruction of the images, an advanced assessment of the lumen and vessel wall morphology can be obtained. To reduce the analysis time and the subjectivity of boundary tracing, automated segmentation of the image sequence must be performed. The Quantitative Coronary Ultrasound-Clinical Measurement Solutions (QCU-CMS) (semi)automated analytical software package uses a combination of transversal and longitudinal model- and knowledge-guided contour detection techniques. On multiple longitudinal sections through the pullback stack, the external vessel contours are detected simultaneously, allowing mutual guidance of the detection in difficult areas. Subsequently, luminal contours are detected on these longitudinal sections. Vessel and luminal contour points are transformed to the individual cross-sections, where they guide the vessel and lumen contour detection on these transversal images. The performance of the software was validated stepwise. A set of phantoms was used to determine the systematic and random errors of the contour detection of external vessel and lumen boundaries. Subsequently, the results of the contour detection as obtained in in vivo image sets were compared with expert manual tracing, and finally the contour detection in in vivo image sequences was compared with results obtained from another previously validated ICUS quantification system. The phantom lumen diameters were underestimated by 0.1 mm, equally by the QCU-CMS software and by manual tracing. Comparison of automatically detected contours and expert manual contours, showed that lumen contours correspond very well (systematic and random radius difference: -0.025 +/- 0.067 mm), while automatically detected vessel contours slightly overestimated the expert manual contours (radius difference: 0.061 +/- 0.037 mm). The cross-sectional vessel and lumen areas as detected with our system and with the second computerized system showed a high correlation (r = 0.995 and 0.978, respectively). Thus, use of the new QCU-CMS analytical software is feasible and the validation data suggest its application for the analysis of clinical research.

Purpose The aim of the study was to determine the feasibility of using a clinical optical breast scanner with molecular imaging strategies based on modulating light transmission. Procedures Different concentrations of single-walled carbon nanotubes (SWNT; 0.8–20.0 nM) and black hole quencher-3 (BHQ-3; 2.0–32.0 μM) were studied in specifically designed phantoms (200–1,570 mm3) with a clinical optical breast scanner using four wavelengths. Each phantom was placed in the scanner tank filled with optical matching medium. Background scans were compared to absorption scans, and reproducibility was assessed. Results All SWNT phantoms were detected at four wavelengths, with best results at 684 nm. Higher concentrations (≥8.0 μM) were needed for BHQ-3 detection, with the largest contrast at 684 nm. The optical absorption signal was dependent on phantom size and concentration. Reproducibility was excellent (intraclass correlation 0.93–0.98). Conclusion Nanomolar concentrations of SWNT and micromolar concentrations of BHQ-3 in phantoms were reproducibly detected, showing the potential of light absorbers, with appropriate targeting ligands, as molecular imaging agents for clinical optical breast imaging.